1. PROTEINS
Proteins are complicated, natural compounds composed of many amino acids linked collectively by means of peptide bonds and cross-linked between chains by sulfhydryl bonds, hydrogen bonds and van der Waals forces. There’s a larger range of chemical composition in proteins than in every other group of biologically energetic compounds. The proteins within the numerous animal and plant cells confer on these tissues their organic specificity.1.1 Classification
Proteins could be labeled as:
(a) Easy proteins. On hydrolysis they yield solely the amino acids and occasional small carbohydrate compounds. Examples are: albumins, globulins, glutelins, albuminoids, histones and protamines.
(b) Conjugated proteins. These are easy proteins mixed with some non-protein materials within the physique. Examples are: nucleoproteins, glycoproteins, phosphoproteins, haemoglobins and lecithoproteins.
(c) Derived proteins. These are proteins derived from easy or conjugated proteins by bodily or chemical means. Examples are: denatured proteins and peptides.1.2 Construction
The potential configuration of protein molecules is so complicated that many forms of protein molecules could be constructed and are present in organic supplies with totally different bodily traits. Globular proteins are present in blood and tissue fluids in amorphous globular type with very skinny or non-existent membranes. Collagenous proteins are present in connective tissue akin to pores and skin or cell membranes. Fibrous proteins are present in hair, muscle and connective tissue. Crystalline proteins are exemplified by the lens of the attention and related tissues. Enzymes are proteins with particular chemical capabilities and mediate many of the physiological processes of life. A number of small polypeptides act as hormones in tissue methods controlling totally different chemical or physiological processes. Muscle protein is made from a number of types of polypeptides that permit muscular contraction and rest for bodily motion.1.3 Properties
Proteins may also be characterised by their chemical reactions. Most proteins are soluble in water, in alcohol, in dilute base or in numerous concentrations of salt options. Proteins have the attribute coiled construction which is set by the sequence of amino acids within the main polypeptide chain and the stereo configuration of the novel teams connected to the alpha carbon of every amino acid. Proteins are warmth labile exhibiting numerous levels of lability relying upon sort of protein, answer and temperature profile. Proteins could be reversible or irreversible, denatured by heating, by salt focus, by freezing, by ultrasonic stress or by getting older. Proteins endure attribute bonding with different proteins within the so-called plastein response and can mix with free aldyhyde and hydroxy teams of carbohydrates to type Maillard sort compounds.1.4 Chemical Dedication
The nitrogen content material of most proteins present in animal, nut and grain tissue is about 16 p.c; subsequently, protein content material is often expressed as nitrogen content material × 6.25.2. PROTEIN DIGESTION AND METABOLISM
Ingested proteins are first break up into smaller fragments by pepsin within the abdomen or by trypsin or chymotrypsin from the pancreas. These peptides are then additional lowered by the motion of carboxypeptidase which hydrolyzes off one amino acid at a time starting on the free carboxyl finish of the molecule or by aminopeptidase which splits off one amino acid at a time starting on the free amino finish of the polypeptide chain. The free amino acids launched into the digestive system are then absorbed by means of the partitions of the gastro intestinal tract into the blood stream the place they’re then resynthesized into new tissue proteins or are catabolyzed for power or for fragments for additional tissue metabolism.3. GROSS PROTEIN REQUIREMENTS
Gross protein necessities have been decided for just a few species of fish (see Desk 1). Simulated entire egg protein part of take a look at diets accommodates an extra of indispensable amino acids. These diets had been stored roughly isocaloric by adjusting whole protein plus digestible carbohydrate parts to a hard and fast quantity because the protein food regimen therapies had been assorted over the ranges examined. Assessments in feeding fry, fingerling, and yearling fish have proven that gross protein necessities are highest in preliminary feeding fry and that they lower as fish dimension will increase. To develop on the most price, fry will need to have a food regimen by which practically half of the digestible elements include balanced protein; at 6-8 weeks this requirement is decreased to about 40 p.c of the food regimen for salmon and trout and to about 35 p.c of the food regimen for yearling salmonids raised at normal environmental temperature (SET). See Figures 1 and a couple of. Gross protein necessities for younger Catfish seem like lower than these for salmonids. Initially feeding fry require that about 50 p.c of the digestible parts of the ration be protein, and the requirement decreases with dimension. Some feeding trials with salmon have indicated direct relationships between modifications within the protein necessities of younger fish and modifications in water temperature. Chinook salmon in 7 C water require about 40 p.c entire egg protein for optimum progress; the identical fish in 15 C water require about 50 p.c protein. Salmon, trout and catfish can use extra protein than required for optimum progress due to effectivity in eliminating nitrogenous wastes within the type of soluble ammonia compounds by means of the gill tissue immediately into the water setting. This technique for eliminating nitrogen is extra environment friendly than that accessible to fowl and mammals. Fowl and mammals eat power to synthesize urea, uric acid, or different nitrogen compounds that are excreted by means of the kidney tissue and expelled in urine. Digestible carbohydrate and fats will spare extra protein within the food regimen so long as the protein requirement for optimum progress is met (Figures 1 and a couple of).
Desk 1 – Estimated Dietary Protein Requirement of Sure Fish 1/
Species
Crude protein degree in food regimen for optimum progress (g/kg)
Rainbow trout (Salmo gairdneri)
400-460
Carp (Cyprinus carpio)
380
Chinook salmon (Oncorhynchus tshawytscha)
400
Eel (Anguilla japonica)
445
Plaice (Pleuronectes platessa)
500
Gilthead bream (Chrysophrys aurata)
400
Grass carp (Ctenopharyngodon idella)
410-430
Brycon sp.
356
Crimson sea bream (Chrysophrys main)
550
Yellowtail (Seriola quinqueradiata)
550
1/Tailored from C.B. Cowey, 1978
Fig. 1. Protein requirement of chinook salmon at 47°F. High curve: preliminary particular person common weight of fish, 1.5g. Backside curve: preliminary particular person common weight of fish, 5.6g.
Fig. 2. Protein requirement of chinook salmon at 58°F. High curve: preliminary particular person common weight of fish, 2.6g. Backside curve: preliminary particular person common weight of fish, 5.8g.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)
Mainly the fish should be given a food regimen containing graded ranges of top of the range protein and power and satisfactory balances of important fatty acids, nutritional vitamins and minerals over a chronic interval. From the ensuing dose/response curve the protein requirement is normally obtained by an Almquist plot. These variations in obvious protein requirement are considered on account of variations in tradition strategies and food regimen composition.
The comparatively excessive dietary protein ranges required for maximal progress of sure fish akin to grass carp, Ctenopharyngodon idella, and Brycon spp. are shocking as these fish are omnivorous. Brycon spp. are grown on undesirable fruit and different plant materials of low protein content material and underneath these situations there may be presumably a considerable contribution to their protein consumption from a pure meals chain.
Protein requirement of eurythaline fish such because the rainbow trout, Salmo gairdneri, and the coho salmon, Oncorhynchus kisutch, reared in water of salinity 20 ppt is about the identical because the requirement in freshwater. No knowledge can be found for the protein requirement of those species in full energy sea water.(35 ppt).
4. AMINO ACIDS
4.1 Important
and Non-essential Amino Acids
4.2 Important
Amino Acids and Protein High quality
The amino acids are the constructing blocks of proteins; about 23 amino acids have been remoted from pure proteins. Ten of those are indispensable for fish. The animal is incapable of synthesizing indispensable amino acids and should subsequently receive these from the food regimen.4.1 Important and Non-essential Amino Acids
Salmon, trout and channel catfish fed diets devoid of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan or valine did not develop (Fig. 3). These identical fish fed diets devoid of different L-amino acids grew in addition to fish receiving all 18 amino acids examined (Fig. 4). The nitrogen part within the take a look at diets was made up of 18 L-amino acids within the sample present in entire egg protein. All fish on take a look at recovered quickly when the lacking amino acid was changed within the food regimen. The slope of the expansion curve of the restoration group was similar with that of fish receiving the entire amino acid take a look at food regimen.
Dispensable amino acids examined had been alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, and tyrosine. These amino acids had been discovered to be not important for the expansion of salmon, trout and channel catfish.
Quantitative research on the necessities of the ten indispensable amino acids used a casein-gelatin combination supplemented with crystalline L-amino acids. The take a look at food regimen had an amino acid sample of 40 p.c entire egg protein for the nitrogen part. Experiments carried out with carp and eel confirmed an identical lack of progress when an indispensable amino acid was absent from the food regimen.
Fig. 3. Development of arginine poor fish. The poor group was divided after six weeks on the poor food regimen and the lacking amino acid was changed in one of many two sub-lots.
Fig. 4. Development of cystine poor fish.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)4.2 Important Amino Acids and Protein High quality
If the important amino acid necessities of fish are recognized, it must be doable to satisfy these wants in tradition methods in a lot of methods from totally different meals proteins or mixtures of meals proteins.
Phenylalanine is spared by tyrosine. It’s not recognized to be chemically modified nor rendered unavailable by the cruel situations to which feedstuff proteins are usually subjected throughout processing. Measurement of phenylalanine in proteins is uncomplicated in order that the availability and analysis of phenylalanine in proteins in sensible diets presents little issue.
Lysine is a primary amino acid. Along with the a -amino acid group usually sure in peptide linkage, it additionally accommodates a second, a -amino group. This a -amino group should be free and reactive, in any other case the lysine, though chemically measurable, won’t be biologically accessible. In the course of the processing of feedstuff proteins the a -amino group of lysine might react with non-protein molecules current within the feedstuff to type extra compounds that render the lysine biologically unavailable.
Methionine is spared by cystine. Nonetheless, measurement of the methionine content material of feed proteins is just not simple because the amino acid is topic to oxidation throughout processing. After processing, methionine could also be current as such or because the sulphoxide or because the sulphone. The sulphoxide could also be fashioned from methionine throughout acid hydrolysis of the feed protein previous to measurement of its any-no acid composition. Acid hydrolysis of proteins earlier than evaluation disturbs the unique equilibrium between the 2 compounds in order that the composition of the hydrolysate not displays that of the protein. In figuring out the methionine content material of pure proteins, oxidation of the amino acid to methionine sulphone is often quantitative. Within the case of feed proteins, nevertheless, this won’t reveal how a lot methionine or methionine sulphoxide was current within the protein previous to performate oxidation and hydrolysis.
Methionine sulphoxide might have some organic worth for fish which can have some functionality of reconverting it to methionine and thus partially make up for a number of the methionine oxidized throughout processing.
Strategies have not too long ago been reported for measurement of methionine in proteins utilizing an iodoplatinate reagent earlier than and after discount with titanium trichloride, to offer values for each methionine and the sulphoxide within the authentic protein. A way for measuring methionine particularly by cyanogen bromide cleavage has additionally been described. Each strategies stay to be independently assessed. Microbiological assay of methionine in feed proteins is a beneficial device though there may be the hazard that oxides of methionine might differ of their exercise for micro-organisms and misrepresent values.5. QUANTITATIVE REQUIREMENTS OF AMINO ACID
Quantitative necessities by salmonids for the ten indispensable amino acids had been decided by feeding linear increments of 1 amino acid at a time in a take a look at food regimen containing an amino acid profile similar with entire egg protein apart from the amino acid examined. Replicate teams of fish had been fed the food regimen therapies till gross variations appeared within the progress of take a look at heaps. An Almquist plot of progress response indicated the extent of amino acids required for optimum progress underneath these particular take a look at situations. Diets had been designed to include protein at or barely beneath the optimum protein requirement for that species and take a look at situation to guarantee most utilization of the limiting amino acid. A comparability of the necessities for the ten indispensable amino acids between species is proven in Desk 2.
A latest innovation has been the use in take a look at diets of proteins comparatively poor in a given important amino acid. Thus mixtures of fishmeal and zein have been utilized in take a look at diets to outline the requirement of rainbow trout for arginine. Diets containing totally different relative quantities of casein and gelatin confirmed that a rise within the degree of protein-bound arginine from 11 to 17 g/kg resulted in a major enhance within the progress of channel catfish.
Desk 2 Amino Acid Necessities of Seven Animals 1/
Amino acid
Eel fingerling
Carp fry
Channel catfish
Chinook salmon fingerling
Chick
Younger Pig
Rat
Arginine
3.9 (1.7/42)
4.3 (1.65/38.5)
6.0 (2.4/40)
6.1 (1.1/18)
1.5 (0.2/13)
1.0 (0.2/19)
Histidine
1.9 (0.8/42)
1.8 (0.7/40)
1.7 (0.3/18)
1.5 (0.2/13)
2.1 (0.4/19)
Isoleucine
3.6 (1.5/42)
2.6 (1.0/38.5)
2.2 (0.9/41)
4.4 (0.8/18)
4.6 (0.6/13)
3.9 (0.5/13)
Leucine
4.1 (1.7/42)
3.9 (1.5/38.5)
3.9 (1.6/41)
6.7 (1.2/18)
4.6 (0.6/13)
4.5 (0.9/19)
Lysine
4.8 (2.0/42)
5.1 (1.23/24.0)
5.0 (2.0/40)
6.1 (1.1/18)
4.7 (0.65/13)
5.4 (1.0/19)
Methionine 2/
4.5 (2.1/42) 3/
3.1 (1.2/38.5)
2.3 (0.56/24.0)
4.0 (1.6/40)3/
4.4 (0.8/18)
3.0 (0.6/20)
3.0 (0.6/20)
Phenylalanine 4/
5.1 (2.1/41)5/
7.2 (1.3/18)
3.6 (0.45/13)
5.3 (0.9/17)
Threonine
3.6 (1.5/42)
2.2 (0.9/40)
3.3 (0.6/18)
3.0 (0.4/13)
3.1 (0.2/19)
Tryptophan
1.0 (0.4/42)
0.5 (0.2/40)
1.1 (0.2/18)
0.8 (0.2/25)
1.0 (0.2/19)
Valine
3.6 (1.5/42)
3.2 (1.3/40)
4.4 (0.8/18)
3.1 (0.4/13)
3.1 (0.4/13)
1/ Expressed as p.c of dietary protein. In parentheses, the numerators are necessities as p.c of dry food regimen, and the denominators are p.c whole protein within the food regimen
2/ Within the absence of cystine
3/ Methionine plus cystine
4/ Within the absence of tyro sine
5/ Phenylalanine plus tyrosine
(Tailored from: Nationwide Analysis Council, 1977)
Arginine requirement of rainbow trout has been decided from a traditional dose/response (progress) curve and in addition by measuring the tissue (blood and muscle) ranges of free arginine in teams of trout given growing quantities of dietary arginine. After the dietary requirement of the trout for arginine has been met, any additional enhance in arginine consumption led to a rise within the focus of free arginine in blood and muscle. Good settlement was obtained between the 2 strategies.
The information proven in Desk 2 recommend that actual variations exist between fish species of their requirement for sure amino acids. This results in difficulties in formulating the protein part of sensible diets for these species whose amino acid necessities should not but recognized. A doable answer is to make use of, for every amino acid, the very best degree required by any of these species for which knowledge is out there. The necessity for additional quantitative knowledge on the amino acid necessities of fish, particularly these truly or doubtlessly helpful as cattle, is clear.6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
2. PROTEIN DIGESTION AND METABOLISM
Ingested proteins are first break up into smaller fragments by pepsin within the abdomen or by trypsin or chymotrypsin from the pancreas. These peptides are then additional lowered by the motion of carboxypeptidase which hydrolyzes off one amino acid at a time starting on the free carboxyl finish of the molecule or by aminopeptidase which splits off one amino acid at a time starting on the free amino finish of the polypeptide chain. The free amino acids launched into the digestive system are then absorbed by means of the partitions of the gastro intestinal tract into the blood stream the place they’re then resynthesized into new tissue proteins or are catabolyzed for power or for fragments for additional tissue metabolism.3. GROSS PROTEIN REQUIREMENTS
Gross protein necessities have been decided for just a few species of fish (see Desk 1). Simulated entire egg protein part of take a look at diets accommodates an extra of indispensable amino acids. These diets had been stored roughly isocaloric by adjusting whole protein plus digestible carbohydrate parts to a hard and fast quantity because the protein food regimen therapies had been assorted over the ranges examined. Assessments in feeding fry, fingerling, and yearling fish have proven that gross protein necessities are highest in preliminary feeding fry and that they lower as fish dimension will increase. To develop on the most price, fry will need to have a food regimen by which practically half of the digestible elements include balanced protein; at 6-8 weeks this requirement is decreased to about 40 p.c of the food regimen for salmon and trout and to about 35 p.c of the food regimen for yearling salmonids raised at normal environmental temperature (SET). See Figures 1 and a couple of. Gross protein necessities for younger Catfish seem like lower than these for salmonids. Initially feeding fry require that about 50 p.c of the digestible parts of the ration be protein, and the requirement decreases with dimension. Some feeding trials with salmon have indicated direct relationships between modifications within the protein necessities of younger fish and modifications in water temperature. Chinook salmon in 7 C water require about 40 p.c entire egg protein for optimum progress; the identical fish in 15 C water require about 50 p.c protein. Salmon, trout and catfish can use extra protein than required for optimum progress due to effectivity in eliminating nitrogenous wastes within the type of soluble ammonia compounds by means of the gill tissue immediately into the water setting. This technique for eliminating nitrogen is extra environment friendly than that accessible to fowl and mammals. Fowl and mammals eat power to synthesize urea, uric acid, or different nitrogen compounds that are excreted by means of the kidney tissue and expelled in urine. Digestible carbohydrate and fats will spare extra protein within the food regimen so long as the protein requirement for optimum progress is met (Figures 1 and a couple of).
Desk 1 – Estimated Dietary Protein Requirement of Sure Fish 1/
Species
Crude protein degree in food regimen for optimum progress (g/kg)
Rainbow trout (Salmo gairdneri)
400-460
Carp (Cyprinus carpio)
380
Chinook salmon (Oncorhynchus tshawytscha)
400
Eel (Anguilla japonica)
445
Plaice (Pleuronectes platessa)
500
Gilthead bream (Chrysophrys aurata)
400
Grass carp (Ctenopharyngodon idella)
410-430
Brycon sp.
356
Crimson sea bream (Chrysophrys main)
550
Yellowtail (Seriola quinqueradiata)
550
1/Tailored from C.B. Cowey, 1978
Fig. 1. Protein requirement of chinook salmon at 47°F. High curve: preliminary particular person common weight of fish, 1.5g. Backside curve: preliminary particular person common weight of fish, 5.6g.
Fig. 2. Protein requirement of chinook salmon at 58°F. High curve: preliminary particular person common weight of fish, 2.6g. Backside curve: preliminary particular person common weight of fish, 5.8g.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)
Mainly the fish should be given a food regimen containing graded ranges of top of the range protein and power and satisfactory balances of important fatty acids, nutritional vitamins and minerals over a chronic interval. From the ensuing dose/response curve the protein requirement is normally obtained by an Almquist plot. These variations in obvious protein requirement are considered on account of variations in tradition strategies and food regimen composition.
The comparatively excessive dietary protein ranges required for maximal progress of sure fish akin to grass carp, Ctenopharyngodon idella, and Brycon spp. are shocking as these fish are omnivorous. Brycon spp. are grown on undesirable fruit and different plant materials of low protein content material and underneath these situations there may be presumably a considerable contribution to their protein consumption from a pure meals chain.
Protein requirement of eurythaline fish such because the rainbow trout, Salmo gairdneri, and the coho salmon, Oncorhynchus kisutch, reared in water of salinity 20 ppt is about the identical because the requirement in freshwater. No knowledge can be found for the protein requirement of those species in full energy sea water.(35 ppt).
4. AMINO ACIDS
4.1 Important
and Non-essential Amino Acids
4.2 Important
Amino Acids and Protein High quality
The amino acids are the constructing blocks of proteins; about 23 amino acids have been remoted from pure proteins. Ten of those are indispensable for fish. The animal is incapable of synthesizing indispensable amino acids and should subsequently receive these from the food regimen.4.1 Important and Non-essential Amino Acids
Salmon, trout and channel catfish fed diets devoid of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan or valine did not develop (Fig. 3). These identical fish fed diets devoid of different L-amino acids grew in addition to fish receiving all 18 amino acids examined (Fig. 4). The nitrogen part within the take a look at diets was made up of 18 L-amino acids within the sample present in entire egg protein. All fish on take a look at recovered quickly when the lacking amino acid was changed within the food regimen. The slope of the expansion curve of the restoration group was similar with that of fish receiving the entire amino acid take a look at food regimen.
Dispensable amino acids examined had been alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, and tyrosine. These amino acids had been discovered to be not important for the expansion of salmon, trout and channel catfish.
Quantitative research on the necessities of the ten indispensable amino acids used a casein-gelatin combination supplemented with crystalline L-amino acids. The take a look at food regimen had an amino acid sample of 40 p.c entire egg protein for the nitrogen part. Experiments carried out with carp and eel confirmed an identical lack of progress when an indispensable amino acid was absent from the food regimen.
Fig. 3. Development of arginine poor fish. The poor group was divided after six weeks on the poor food regimen and the lacking amino acid was changed in one of many two sub-lots.
Fig. 4. Development of cystine poor fish.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)4.2 Important Amino Acids and Protein High quality
If the important amino acid necessities of fish are recognized, it must be doable to satisfy these wants in tradition methods in a lot of methods from totally different meals proteins or mixtures of meals proteins.
Phenylalanine is spared by tyrosine. It’s not recognized to be chemically modified nor rendered unavailable by the cruel situations to which feedstuff proteins are usually subjected throughout processing. Measurement of phenylalanine in proteins is uncomplicated in order that the availability and analysis of phenylalanine in proteins in sensible diets presents little issue.
Lysine is a primary amino acid. Along with the a -amino acid group usually sure in peptide linkage, it additionally accommodates a second, a -amino group. This a -amino group should be free and reactive, in any other case the lysine, though chemically measurable, won’t be biologically accessible. In the course of the processing of feedstuff proteins the a -amino group of lysine might react with non-protein molecules current within the feedstuff to type extra compounds that render the lysine biologically unavailable.
Methionine is spared by cystine. Nonetheless, measurement of the methionine content material of feed proteins is just not simple because the amino acid is topic to oxidation throughout processing. After processing, methionine could also be current as such or because the sulphoxide or because the sulphone. The sulphoxide could also be fashioned from methionine throughout acid hydrolysis of the feed protein previous to measurement of its any-no acid composition. Acid hydrolysis of proteins earlier than evaluation disturbs the unique equilibrium between the 2 compounds in order that the composition of the hydrolysate not displays that of the protein. In figuring out the methionine content material of pure proteins, oxidation of the amino acid to methionine sulphone is often quantitative. Within the case of feed proteins, nevertheless, this won’t reveal how a lot methionine or methionine sulphoxide was current within the protein previous to performate oxidation and hydrolysis.
Methionine sulphoxide might have some organic worth for fish which can have some functionality of reconverting it to methionine and thus partially make up for a number of the methionine oxidized throughout processing.
Strategies have not too long ago been reported for measurement of methionine in proteins utilizing an iodoplatinate reagent earlier than and after discount with titanium trichloride, to offer values for each methionine and the sulphoxide within the authentic protein. A way for measuring methionine particularly by cyanogen bromide cleavage has additionally been described. Each strategies stay to be independently assessed. Microbiological assay of methionine in feed proteins is a beneficial device though there may be the hazard that oxides of methionine might differ of their exercise for micro-organisms and misrepresent values.5. QUANTITATIVE REQUIREMENTS OF AMINO ACID
Quantitative necessities by salmonids for the ten indispensable amino acids had been decided by feeding linear increments of 1 amino acid at a time in a take a look at food regimen containing an amino acid profile similar with entire egg protein apart from the amino acid examined. Replicate teams of fish had been fed the food regimen therapies till gross variations appeared within the progress of take a look at heaps. An Almquist plot of progress response indicated the extent of amino acids required for optimum progress underneath these particular take a look at situations. Diets had been designed to include protein at or barely beneath the optimum protein requirement for that species and take a look at situation to guarantee most utilization of the limiting amino acid. A comparability of the necessities for the ten indispensable amino acids between species is proven in Desk 2.
A latest innovation has been the use in take a look at diets of proteins comparatively poor in a given important amino acid. Thus mixtures of fishmeal and zein have been utilized in take a look at diets to outline the requirement of rainbow trout for arginine. Diets containing totally different relative quantities of casein and gelatin confirmed that a rise within the degree of protein-bound arginine from 11 to 17 g/kg resulted in a major enhance within the progress of channel catfish.
Desk 2 Amino Acid Necessities of Seven Animals 1/
Amino acid
Eel fingerling
Carp fry
Channel catfish
Chinook salmon fingerling
Chick
Younger Pig
Rat
Arginine
3.9 (1.7/42)
4.3 (1.65/38.5)
6.0 (2.4/40)
6.1 (1.1/18)
1.5 (0.2/13)
1.0 (0.2/19)
Histidine
1.9 (0.8/42)
1.8 (0.7/40)
1.7 (0.3/18)
1.5 (0.2/13)
2.1 (0.4/19)
Isoleucine
3.6 (1.5/42)
2.6 (1.0/38.5)
2.2 (0.9/41)
4.4 (0.8/18)
4.6 (0.6/13)
3.9 (0.5/13)
Leucine
4.1 (1.7/42)
3.9 (1.5/38.5)
3.9 (1.6/41)
6.7 (1.2/18)
4.6 (0.6/13)
4.5 (0.9/19)
Lysine
4.8 (2.0/42)
5.1 (1.23/24.0)
5.0 (2.0/40)
6.1 (1.1/18)
4.7 (0.65/13)
5.4 (1.0/19)
Methionine 2/
4.5 (2.1/42) 3/
3.1 (1.2/38.5)
2.3 (0.56/24.0)
4.0 (1.6/40)3/
4.4 (0.8/18)
3.0 (0.6/20)
3.0 (0.6/20)
Phenylalanine 4/
5.1 (2.1/41)5/
7.2 (1.3/18)
3.6 (0.45/13)
5.3 (0.9/17)
Threonine
3.6 (1.5/42)
2.2 (0.9/40)
3.3 (0.6/18)
3.0 (0.4/13)
3.1 (0.2/19)
Tryptophan
1.0 (0.4/42)
0.5 (0.2/40)
1.1 (0.2/18)
0.8 (0.2/25)
1.0 (0.2/19)
Valine
3.6 (1.5/42)
3.2 (1.3/40)
4.4 (0.8/18)
3.1 (0.4/13)
3.1 (0.4/13)
1/ Expressed as p.c of dietary protein. In parentheses, the numerators are necessities as p.c of dry food regimen, and the denominators are p.c whole protein within the food regimen
2/ Within the absence of cystine
3/ Methionine plus cystine
4/ Within the absence of tyro sine
5/ Phenylalanine plus tyrosine
(Tailored from: Nationwide Analysis Council, 1977)
Arginine requirement of rainbow trout has been decided from a traditional dose/response (progress) curve and in addition by measuring the tissue (blood and muscle) ranges of free arginine in teams of trout given growing quantities of dietary arginine. After the dietary requirement of the trout for arginine has been met, any additional enhance in arginine consumption led to a rise within the focus of free arginine in blood and muscle. Good settlement was obtained between the 2 strategies.
The information proven in Desk 2 recommend that actual variations exist between fish species of their requirement for sure amino acids. This results in difficulties in formulating the protein part of sensible diets for these species whose amino acid necessities should not but recognized. A doable answer is to make use of, for every amino acid, the very best degree required by any of these species for which knowledge is out there. The necessity for additional quantitative knowledge on the amino acid necessities of fish, particularly these truly or doubtlessly helpful as cattle, is clear.6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
3. GROSS PROTEIN REQUIREMENTS
Gross protein necessities have been decided for just a few species of fish (see Desk 1). Simulated entire egg protein part of take a look at diets accommodates an extra of indispensable amino acids. These diets had been stored roughly isocaloric by adjusting whole protein plus digestible carbohydrate parts to a hard and fast quantity because the protein food regimen therapies had been assorted over the ranges examined. Assessments in feeding fry, fingerling, and yearling fish have proven that gross protein necessities are highest in preliminary feeding fry and that they lower as fish dimension will increase. To develop on the most price, fry will need to have a food regimen by which practically half of the digestible elements include balanced protein; at 6-8 weeks this requirement is decreased to about 40 p.c of the food regimen for salmon and trout and to about 35 p.c of the food regimen for yearling salmonids raised at normal environmental temperature (SET). See Figures 1 and a couple of. Gross protein necessities for younger Catfish seem like lower than these for salmonids. Initially feeding fry require that about 50 p.c of the digestible parts of the ration be protein, and the requirement decreases with dimension. Some feeding trials with salmon have indicated direct relationships between modifications within the protein necessities of younger fish and modifications in water temperature. Chinook salmon in 7 C water require about 40 p.c entire egg protein for optimum progress; the identical fish in 15 C water require about 50 p.c protein. Salmon, trout and catfish can use extra protein than required for optimum progress due to effectivity in eliminating nitrogenous wastes within the type of soluble ammonia compounds by means of the gill tissue immediately into the water setting. This technique for eliminating nitrogen is extra environment friendly than that accessible to fowl and mammals. Fowl and mammals eat power to synthesize urea, uric acid, or different nitrogen compounds that are excreted by means of the kidney tissue and expelled in urine. Digestible carbohydrate and fats will spare extra protein within the food regimen so long as the protein requirement for optimum progress is met (Figures 1 and a couple of).
Desk 1 – Estimated Dietary Protein Requirement of Sure Fish 1/
Species
Crude protein degree in food regimen for optimum progress (g/kg)
Rainbow trout (Salmo gairdneri)
400-460
Carp (Cyprinus carpio)
380
Chinook salmon (Oncorhynchus tshawytscha)
400
Eel (Anguilla japonica)
445
Plaice (Pleuronectes platessa)
500
Gilthead bream (Chrysophrys aurata)
400
Grass carp (Ctenopharyngodon idella)
410-430
Brycon sp.
356
Crimson sea bream (Chrysophrys main)
550
Yellowtail (Seriola quinqueradiata)
550
1/Tailored from C.B. Cowey, 1978
Fig. 1. Protein requirement of chinook salmon at 47°F. High curve: preliminary particular person common weight of fish, 1.5g. Backside curve: preliminary particular person common weight of fish, 5.6g.
Fig. 2. Protein requirement of chinook salmon at 58°F. High curve: preliminary particular person common weight of fish, 2.6g. Backside curve: preliminary particular person common weight of fish, 5.8g.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)
Mainly the fish should be given a food regimen containing graded ranges of top of the range protein and power and satisfactory balances of important fatty acids, nutritional vitamins and minerals over a chronic interval. From the ensuing dose/response curve the protein requirement is normally obtained by an Almquist plot. These variations in obvious protein requirement are considered on account of variations in tradition strategies and food regimen composition.
The comparatively excessive dietary protein ranges required for maximal progress of sure fish akin to grass carp, Ctenopharyngodon idella, and Brycon spp. are shocking as these fish are omnivorous. Brycon spp. are grown on undesirable fruit and different plant materials of low protein content material and underneath these situations there may be presumably a considerable contribution to their protein consumption from a pure meals chain.
Protein requirement of eurythaline fish such because the rainbow trout, Salmo gairdneri, and the coho salmon, Oncorhynchus kisutch, reared in water of salinity 20 ppt is about the identical because the requirement in freshwater. No knowledge can be found for the protein requirement of those species in full energy sea water.(35 ppt).
4. AMINO ACIDS
4.1 Important
and Non-essential Amino Acids
4.2 Important
Amino Acids and Protein High quality
The amino acids are the constructing blocks of proteins; about 23 amino acids have been remoted from pure proteins. Ten of those are indispensable for fish. The animal is incapable of synthesizing indispensable amino acids and should subsequently receive these from the food regimen.4.1 Important and Non-essential Amino Acids
Salmon, trout and channel catfish fed diets devoid of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan or valine did not develop (Fig. 3). These identical fish fed diets devoid of different L-amino acids grew in addition to fish receiving all 18 amino acids examined (Fig. 4). The nitrogen part within the take a look at diets was made up of 18 L-amino acids within the sample present in entire egg protein. All fish on take a look at recovered quickly when the lacking amino acid was changed within the food regimen. The slope of the expansion curve of the restoration group was similar with that of fish receiving the entire amino acid take a look at food regimen.
Dispensable amino acids examined had been alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, and tyrosine. These amino acids had been discovered to be not important for the expansion of salmon, trout and channel catfish.
Quantitative research on the necessities of the ten indispensable amino acids used a casein-gelatin combination supplemented with crystalline L-amino acids. The take a look at food regimen had an amino acid sample of 40 p.c entire egg protein for the nitrogen part. Experiments carried out with carp and eel confirmed an identical lack of progress when an indispensable amino acid was absent from the food regimen.
Fig. 3. Development of arginine poor fish. The poor group was divided after six weeks on the poor food regimen and the lacking amino acid was changed in one of many two sub-lots.
Fig. 4. Development of cystine poor fish.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)4.2 Important Amino Acids and Protein High quality
If the important amino acid necessities of fish are recognized, it must be doable to satisfy these wants in tradition methods in a lot of methods from totally different meals proteins or mixtures of meals proteins.
Phenylalanine is spared by tyrosine. It’s not recognized to be chemically modified nor rendered unavailable by the cruel situations to which feedstuff proteins are usually subjected throughout processing. Measurement of phenylalanine in proteins is uncomplicated in order that the availability and analysis of phenylalanine in proteins in sensible diets presents little issue.
Lysine is a primary amino acid. Along with the a -amino acid group usually sure in peptide linkage, it additionally accommodates a second, a -amino group. This a -amino group should be free and reactive, in any other case the lysine, though chemically measurable, won’t be biologically accessible. In the course of the processing of feedstuff proteins the a -amino group of lysine might react with non-protein molecules current within the feedstuff to type extra compounds that render the lysine biologically unavailable.
Methionine is spared by cystine. Nonetheless, measurement of the methionine content material of feed proteins is just not simple because the amino acid is topic to oxidation throughout processing. After processing, methionine could also be current as such or because the sulphoxide or because the sulphone. The sulphoxide could also be fashioned from methionine throughout acid hydrolysis of the feed protein previous to measurement of its any-no acid composition. Acid hydrolysis of proteins earlier than evaluation disturbs the unique equilibrium between the 2 compounds in order that the composition of the hydrolysate not displays that of the protein. In figuring out the methionine content material of pure proteins, oxidation of the amino acid to methionine sulphone is often quantitative. Within the case of feed proteins, nevertheless, this won’t reveal how a lot methionine or methionine sulphoxide was current within the protein previous to performate oxidation and hydrolysis.
Methionine sulphoxide might have some organic worth for fish which can have some functionality of reconverting it to methionine and thus partially make up for a number of the methionine oxidized throughout processing.
Strategies have not too long ago been reported for measurement of methionine in proteins utilizing an iodoplatinate reagent earlier than and after discount with titanium trichloride, to offer values for each methionine and the sulphoxide within the authentic protein. A way for measuring methionine particularly by cyanogen bromide cleavage has additionally been described. Each strategies stay to be independently assessed. Microbiological assay of methionine in feed proteins is a beneficial device though there may be the hazard that oxides of methionine might differ of their exercise for micro-organisms and misrepresent values.5. QUANTITATIVE REQUIREMENTS OF AMINO ACID
Quantitative necessities by salmonids for the ten indispensable amino acids had been decided by feeding linear increments of 1 amino acid at a time in a take a look at food regimen containing an amino acid profile similar with entire egg protein apart from the amino acid examined. Replicate teams of fish had been fed the food regimen therapies till gross variations appeared within the progress of take a look at heaps. An Almquist plot of progress response indicated the extent of amino acids required for optimum progress underneath these particular take a look at situations. Diets had been designed to include protein at or barely beneath the optimum protein requirement for that species and take a look at situation to guarantee most utilization of the limiting amino acid. A comparability of the necessities for the ten indispensable amino acids between species is proven in Desk 2.
A latest innovation has been the use in take a look at diets of proteins comparatively poor in a given important amino acid. Thus mixtures of fishmeal and zein have been utilized in take a look at diets to outline the requirement of rainbow trout for arginine. Diets containing totally different relative quantities of casein and gelatin confirmed that a rise within the degree of protein-bound arginine from 11 to 17 g/kg resulted in a major enhance within the progress of channel catfish.
Desk 2 Amino Acid Necessities of Seven Animals 1/
Amino acid
Eel fingerling
Carp fry
Channel catfish
Chinook salmon fingerling
Chick
Younger Pig
Rat
Arginine
3.9 (1.7/42)
4.3 (1.65/38.5)
6.0 (2.4/40)
6.1 (1.1/18)
1.5 (0.2/13)
1.0 (0.2/19)
Histidine
1.9 (0.8/42)
1.8 (0.7/40)
1.7 (0.3/18)
1.5 (0.2/13)
2.1 (0.4/19)
Isoleucine
3.6 (1.5/42)
2.6 (1.0/38.5)
2.2 (0.9/41)
4.4 (0.8/18)
4.6 (0.6/13)
3.9 (0.5/13)
Leucine
4.1 (1.7/42)
3.9 (1.5/38.5)
3.9 (1.6/41)
6.7 (1.2/18)
4.6 (0.6/13)
4.5 (0.9/19)
Lysine
4.8 (2.0/42)
5.1 (1.23/24.0)
5.0 (2.0/40)
6.1 (1.1/18)
4.7 (0.65/13)
5.4 (1.0/19)
Methionine 2/
4.5 (2.1/42) 3/
3.1 (1.2/38.5)
2.3 (0.56/24.0)
4.0 (1.6/40)3/
4.4 (0.8/18)
3.0 (0.6/20)
3.0 (0.6/20)
Phenylalanine 4/
5.1 (2.1/41)5/
7.2 (1.3/18)
3.6 (0.45/13)
5.3 (0.9/17)
Threonine
3.6 (1.5/42)
2.2 (0.9/40)
3.3 (0.6/18)
3.0 (0.4/13)
3.1 (0.2/19)
Tryptophan
1.0 (0.4/42)
0.5 (0.2/40)
1.1 (0.2/18)
0.8 (0.2/25)
1.0 (0.2/19)
Valine
3.6 (1.5/42)
3.2 (1.3/40)
4.4 (0.8/18)
3.1 (0.4/13)
3.1 (0.4/13)
1/ Expressed as p.c of dietary protein. In parentheses, the numerators are necessities as p.c of dry food regimen, and the denominators are p.c whole protein within the food regimen
2/ Within the absence of cystine
3/ Methionine plus cystine
4/ Within the absence of tyro sine
5/ Phenylalanine plus tyrosine
(Tailored from: Nationwide Analysis Council, 1977)
Arginine requirement of rainbow trout has been decided from a traditional dose/response (progress) curve and in addition by measuring the tissue (blood and muscle) ranges of free arginine in teams of trout given growing quantities of dietary arginine. After the dietary requirement of the trout for arginine has been met, any additional enhance in arginine consumption led to a rise within the focus of free arginine in blood and muscle. Good settlement was obtained between the 2 strategies.
The information proven in Desk 2 recommend that actual variations exist between fish species of their requirement for sure amino acids. This results in difficulties in formulating the protein part of sensible diets for these species whose amino acid necessities should not but recognized. A doable answer is to make use of, for every amino acid, the very best degree required by any of these species for which knowledge is out there. The necessity for additional quantitative knowledge on the amino acid necessities of fish, particularly these truly or doubtlessly helpful as cattle, is clear.6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
4. AMINO ACIDS
The amino acids are the constructing blocks of proteins; about 23 amino acids have been remoted from pure proteins. Ten of those are indispensable for fish. The animal is incapable of synthesizing indispensable amino acids and should subsequently receive these from the food regimen.4.1 Important and Non-essential Amino Acids
Salmon, trout and channel catfish fed diets devoid of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan or valine did not develop (Fig. 3). These identical fish fed diets devoid of different L-amino acids grew in addition to fish receiving all 18 amino acids examined (Fig. 4). The nitrogen part within the take a look at diets was made up of 18 L-amino acids within the sample present in entire egg protein. All fish on take a look at recovered quickly when the lacking amino acid was changed within the food regimen. The slope of the expansion curve of the restoration group was similar with that of fish receiving the entire amino acid take a look at food regimen.
Dispensable amino acids examined had been alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, and tyrosine. These amino acids had been discovered to be not important for the expansion of salmon, trout and channel catfish.
Quantitative research on the necessities of the ten indispensable amino acids used a casein-gelatin combination supplemented with crystalline L-amino acids. The take a look at food regimen had an amino acid sample of 40 p.c entire egg protein for the nitrogen part. Experiments carried out with carp and eel confirmed an identical lack of progress when an indispensable amino acid was absent from the food regimen.
Fig. 3. Development of arginine poor fish. The poor group was divided after six weeks on the poor food regimen and the lacking amino acid was changed in one of many two sub-lots.
Fig. 4. Development of cystine poor fish.
(Each figures tailored from: DeLong, D.C., J.E. Halver and E.T. Mertz, 1958, J.Nutr., 65:589-99)4.2 Important Amino Acids and Protein High quality
If the important amino acid necessities of fish are recognized, it must be doable to satisfy these wants in tradition methods in a lot of methods from totally different meals proteins or mixtures of meals proteins.
Phenylalanine is spared by tyrosine. It’s not recognized to be chemically modified nor rendered unavailable by the cruel situations to which feedstuff proteins are usually subjected throughout processing. Measurement of phenylalanine in proteins is uncomplicated in order that the availability and analysis of phenylalanine in proteins in sensible diets presents little issue.
Lysine is a primary amino acid. Along with the a -amino acid group usually sure in peptide linkage, it additionally accommodates a second, a -amino group. This a -amino group should be free and reactive, in any other case the lysine, though chemically measurable, won’t be biologically accessible. In the course of the processing of feedstuff proteins the a -amino group of lysine might react with non-protein molecules current within the feedstuff to type extra compounds that render the lysine biologically unavailable.
Methionine is spared by cystine. Nonetheless, measurement of the methionine content material of feed proteins is just not simple because the amino acid is topic to oxidation throughout processing. After processing, methionine could also be current as such or because the sulphoxide or because the sulphone. The sulphoxide could also be fashioned from methionine throughout acid hydrolysis of the feed protein previous to measurement of its any-no acid composition. Acid hydrolysis of proteins earlier than evaluation disturbs the unique equilibrium between the 2 compounds in order that the composition of the hydrolysate not displays that of the protein. In figuring out the methionine content material of pure proteins, oxidation of the amino acid to methionine sulphone is often quantitative. Within the case of feed proteins, nevertheless, this won’t reveal how a lot methionine or methionine sulphoxide was current within the protein previous to performate oxidation and hydrolysis.
Methionine sulphoxide might have some organic worth for fish which can have some functionality of reconverting it to methionine and thus partially make up for a number of the methionine oxidized throughout processing.
Strategies have not too long ago been reported for measurement of methionine in proteins utilizing an iodoplatinate reagent earlier than and after discount with titanium trichloride, to offer values for each methionine and the sulphoxide within the authentic protein. A way for measuring methionine particularly by cyanogen bromide cleavage has additionally been described. Each strategies stay to be independently assessed. Microbiological assay of methionine in feed proteins is a beneficial device though there may be the hazard that oxides of methionine might differ of their exercise for micro-organisms and misrepresent values.5. QUANTITATIVE REQUIREMENTS OF AMINO ACID
Quantitative necessities by salmonids for the ten indispensable amino acids had been decided by feeding linear increments of 1 amino acid at a time in a take a look at food regimen containing an amino acid profile similar with entire egg protein apart from the amino acid examined. Replicate teams of fish had been fed the food regimen therapies till gross variations appeared within the progress of take a look at heaps. An Almquist plot of progress response indicated the extent of amino acids required for optimum progress underneath these particular take a look at situations. Diets had been designed to include protein at or barely beneath the optimum protein requirement for that species and take a look at situation to guarantee most utilization of the limiting amino acid. A comparability of the necessities for the ten indispensable amino acids between species is proven in Desk 2.
A latest innovation has been the use in take a look at diets of proteins comparatively poor in a given important amino acid. Thus mixtures of fishmeal and zein have been utilized in take a look at diets to outline the requirement of rainbow trout for arginine. Diets containing totally different relative quantities of casein and gelatin confirmed that a rise within the degree of protein-bound arginine from 11 to 17 g/kg resulted in a major enhance within the progress of channel catfish.
Desk 2 Amino Acid Necessities of Seven Animals 1/
Amino acid
Eel fingerling
Carp fry
Channel catfish
Chinook salmon fingerling
Chick
Younger Pig
Rat
Arginine
3.9 (1.7/42)
4.3 (1.65/38.5)
6.0 (2.4/40)
6.1 (1.1/18)
1.5 (0.2/13)
1.0 (0.2/19)
Histidine
1.9 (0.8/42)
1.8 (0.7/40)
1.7 (0.3/18)
1.5 (0.2/13)
2.1 (0.4/19)
Isoleucine
3.6 (1.5/42)
2.6 (1.0/38.5)
2.2 (0.9/41)
4.4 (0.8/18)
4.6 (0.6/13)
3.9 (0.5/13)
Leucine
4.1 (1.7/42)
3.9 (1.5/38.5)
3.9 (1.6/41)
6.7 (1.2/18)
4.6 (0.6/13)
4.5 (0.9/19)
Lysine
4.8 (2.0/42)
5.1 (1.23/24.0)
5.0 (2.0/40)
6.1 (1.1/18)
4.7 (0.65/13)
5.4 (1.0/19)
Methionine 2/
4.5 (2.1/42) 3/
3.1 (1.2/38.5)
2.3 (0.56/24.0)
4.0 (1.6/40)3/
4.4 (0.8/18)
3.0 (0.6/20)
3.0 (0.6/20)
Phenylalanine 4/
5.1 (2.1/41)5/
7.2 (1.3/18)
3.6 (0.45/13)
5.3 (0.9/17)
Threonine
3.6 (1.5/42)
2.2 (0.9/40)
3.3 (0.6/18)
3.0 (0.4/13)
3.1 (0.2/19)
Tryptophan
1.0 (0.4/42)
0.5 (0.2/40)
1.1 (0.2/18)
0.8 (0.2/25)
1.0 (0.2/19)
Valine
3.6 (1.5/42)
3.2 (1.3/40)
4.4 (0.8/18)
3.1 (0.4/13)
3.1 (0.4/13)
1/ Expressed as p.c of dietary protein. In parentheses, the numerators are necessities as p.c of dry food regimen, and the denominators are p.c whole protein within the food regimen
2/ Within the absence of cystine
3/ Methionine plus cystine
4/ Within the absence of tyro sine
5/ Phenylalanine plus tyrosine
(Tailored from: Nationwide Analysis Council, 1977)
Arginine requirement of rainbow trout has been decided from a traditional dose/response (progress) curve and in addition by measuring the tissue (blood and muscle) ranges of free arginine in teams of trout given growing quantities of dietary arginine. After the dietary requirement of the trout for arginine has been met, any additional enhance in arginine consumption led to a rise within the focus of free arginine in blood and muscle. Good settlement was obtained between the 2 strategies.
The information proven in Desk 2 recommend that actual variations exist between fish species of their requirement for sure amino acids. This results in difficulties in formulating the protein part of sensible diets for these species whose amino acid necessities should not but recognized. A doable answer is to make use of, for every amino acid, the very best degree required by any of these species for which knowledge is out there. The necessity for additional quantitative knowledge on the amino acid necessities of fish, particularly these truly or doubtlessly helpful as cattle, is clear.6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
5. QUANTITATIVE REQUIREMENTS OF AMINO ACID – “what’s the difference between protein and amino acids”
Quantitative necessities by salmonids for the ten indispensable amino acids had been decided by feeding linear increments of 1 amino acid at a time in a take a look at food regimen containing an amino acid profile similar with entire egg protein apart from the amino acid examined. Replicate teams of fish had been fed the food regimen therapies till gross variations appeared within the progress of take a look at heaps. An Almquist plot of progress response indicated the extent of amino acids required for optimum progress underneath these particular take a look at situations. Diets had been designed to include protein at or barely beneath the optimum protein requirement for that species and take a look at situation to guarantee most utilization of the limiting amino acid. A comparability of the necessities for the ten indispensable amino acids between species is proven in Desk 2.
A latest innovation has been the use in take a look at diets of proteins comparatively poor in a given important amino acid. Thus mixtures of fishmeal and zein have been utilized in take a look at diets to outline the requirement of rainbow trout for arginine. Diets containing totally different relative quantities of casein and gelatin confirmed that a rise within the degree of protein-bound arginine from 11 to 17 g/kg resulted in a major enhance within the progress of channel catfish.
Desk 2 Amino Acid Necessities of Seven Animals 1/
Amino acid
Eel fingerling
Carp fry
Channel catfish
Chinook salmon fingerling
Chick
Younger Pig
Rat
Arginine
3.9 (1.7/42)
4.3 (1.65/38.5)
6.0 (2.4/40)
6.1 (1.1/18)
1.5 (0.2/13)
1.0 (0.2/19)
Histidine
1.9 (0.8/42)
1.8 (0.7/40)
1.7 (0.3/18)
1.5 (0.2/13)
2.1 (0.4/19)
Isoleucine
3.6 (1.5/42)
2.6 (1.0/38.5)
2.2 (0.9/41)
4.4 (0.8/18)
4.6 (0.6/13)
3.9 (0.5/13)
Leucine
4.1 (1.7/42)
3.9 (1.5/38.5)
3.9 (1.6/41)
6.7 (1.2/18)
4.6 (0.6/13)
4.5 (0.9/19)
Lysine
4.8 (2.0/42)
5.1 (1.23/24.0)
5.0 (2.0/40)
6.1 (1.1/18)
4.7 (0.65/13)
5.4 (1.0/19)
Methionine 2/
4.5 (2.1/42) 3/
3.1 (1.2/38.5)
2.3 (0.56/24.0)
4.0 (1.6/40)3/
4.4 (0.8/18)
3.0 (0.6/20)
3.0 (0.6/20)
Phenylalanine 4/
5.1 (2.1/41)5/
7.2 (1.3/18)
3.6 (0.45/13)
5.3 (0.9/17)
Threonine
3.6 (1.5/42)
2.2 (0.9/40)
3.3 (0.6/18)
3.0 (0.4/13)
3.1 (0.2/19)
Tryptophan
1.0 (0.4/42)
0.5 (0.2/40)
1.1 (0.2/18)
0.8 (0.2/25)
1.0 (0.2/19)
Valine
3.6 (1.5/42)
3.2 (1.3/40)
4.4 (0.8/18)
3.1 (0.4/13)
3.1 (0.4/13)
1/ Expressed as p.c of dietary protein. In parentheses, the numerators are necessities as p.c of dry food regimen, and the denominators are p.c whole protein within the food regimen
2/ Within the absence of cystine
3/ Methionine plus cystine
4/ Within the absence of tyro sine
5/ Phenylalanine plus tyrosine
(Tailored from: Nationwide Analysis Council, 1977)
Arginine requirement of rainbow trout has been decided from a traditional dose/response (progress) curve and in addition by measuring the tissue (blood and muscle) ranges of free arginine in teams of trout given growing quantities of dietary arginine. After the dietary requirement of the trout for arginine has been met, any additional enhance in arginine consumption led to a rise within the focus of free arginine in blood and muscle. Good settlement was obtained between the 2 strategies.
The information proven in Desk 2 recommend that actual variations exist between fish species of their requirement for sure amino acids. This results in difficulties in formulating the protein part of sensible diets for these species whose amino acid necessities should not but recognized. A doable answer is to make use of, for every amino acid, the very best degree required by any of these species for which knowledge is out there. The necessity for additional quantitative knowledge on the amino acid necessities of fish, particularly these truly or doubtlessly helpful as cattle, is clear.6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
6. SUPPLEMENTING DIETS WITH AMINO ACIDS
One answer to using proteins which are comparatively poor in a number of amino acids is to complement the protein with acceptable quantities of the amino acid wanted in sensible diets. Fish seem to make the most of free amino acids at numerous levels of effectivity.
Younger carp, Cyprinus carpio, had been proven to be unable to develop on diets by which the protein part (casein, gelatin) was changed by a mix of amino acids related in total composition. A trypsin hydrolyzate of casein was equally ineffective. Nonetheless, if a food regimen containing free amino acids because the protein part is rigorously neutralized with NaOH to pH 6.5-6.7 then some progress of younger carp does happen. This progress was markedly inferior to that occurring on a comparable casein food regimen underneath the identical situations.
Channel catfish are additionally unable to make the most of free amino acids given as dietary supplements to poor proteins. When soybean meal was substituted isonitrogenously for menhaden meal, progress and feed effectivity of channel catfish had been considerably lowered. Addition of free methionine, cystine or lysine, probably the most limiting amino acids, to those soy-substituted diets didn’t improve weight acquire.
Elevating the arginine degree of catfish diets from 11 to 17 g/kg by isonitrogenous substitution of gelatin for casein enhanced weight acquire considerably however the addition of free arginine, cystine, tryptophan or methionine to casein had little impact on progress or meals conversion.
Salmonids are in a position to make the most of free amino acids for progress. A zein-gelatin food regimen supplemented with lysine and trytophan was proven to be markedly superior to an unsupplemented zein-gelatin food regimen for rainbow trout when weight acquire and protein utilization had been used as standards.
A number of investigators have demonstrated the potential of supplementing amino acid poor proteins with limiting amino acids in diets for salmonids. Casein supplemented with six amino acids produced feed conversion ratios with Atlantic salmon much like these obtained when an remoted fish protein was used because the dietary protein supply. Soybean meal supplemented with 5 or extra amino acids (together with methionine and lysine) was a superior protein supply to soybean meal alone for rainbow trout. Single additions of methionine and lysine didn’t, nevertheless, enhance the worth of soybean meal. These outcomes recommend that the amino acid spectrum of the remoted fish protein they used might presumably approximate the amino acid requirement of rainbow trout. The dietary worth of a soy protein isolate might be enhanced by supplementing it with the primary limiting amino acid; i.e., methionine.
Diets containing, as protein part, fishmeal, meat and bone meal, and yeast and soybean meal might be improved by supplementing with cystine (10 g/kg) and tryptophan (5 g/kg) collectively. Fishmeal could be solely changed with no discount in meals conversion price in diets for rainbow trout by a mix of poultry by-product meal and feather meal along with 17 g lysine HCL/kg, 4.8 g DL-methionine/kg, and 1.44 g DL-tryptophan/kg.7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
7. REFERENCES
Cowey, C.B. and J.R. Sargent, 1972 Fish vitamin. Adv.Mar.Biol., 10:383-492
Cowey, C.B., 1979 Protein and amino acid necessities of finfish. In Finfish vitamin and fishfeed know-how, edited by J.E. Halver and Ok. Tiews. Proceedings of a World Symposium sponsored by EIFAC/FAO, ICES and IUNS, Hamburg, 20-23 June, 1978. Schr.Bundesforschungsanst.Fisch.,Hamb., (14/15)vol. 1:3-16
Mertz, E.T., 1972 The protein and amino acid wants. In Fish vitamin, edited by J.E. Halver. New York, Tutorial Press, pp. 106-43
Nationwide Analysis Council, 1977 Subcommittee on Warmwater Fishes, Nutrient necessities of warmwater fishes. Washington, D.C., Nationwide Academy of Sciences (Nutrient necessities of home animals) 78 p.
“what’s the difference between protein and amino acids”