3.4 Quantitative Amino Acid Requirements
3.4.4. Branched-Chain Amino Acid Requirements
The isoleucine requirements of fish are presented in Table 3.6. The re- quirement appears to be about 2.2 to 3% of protein for those species studied except for the Japanese eel and milkfish, which have higher requirement values.
Wilsonet al.(1980) determined the effects of dietary isoleucine on serum free isoleucine, leucine, and valine in channel catfish. Even though the serum isoleucine increased somewhat with increasing isoleucine intake, these data did not confirm the requirement as determined based on growth data. The serum free leucine and valine concentrations appeared to parallel the serum free isoleucine concentrations. A relative high mortality rate was observed in fish fed the isoleucine-deficient diet.
Table 3.6
Isoleucine Requirements
Fish Requirementa Based on Reference
Atlantic salmon 3.2 Ideal protein Rollin (1999)
Catla 2.4 Growth studies Ravi and Devaraj (1991)
Channel catfish 2.6 Growth studies Wilsonet al. (1980) Chinook salmon 2.2 Growth studies Chanceet al. (1964)
Chum salmon 2.4 Growth studies Akiyama and Arai (1993)
Clariashybrid 2.0 Ideal protein Unprasert (1994)
Coho salmon 1.2 Growth studies Arai and Ogata (1993)
Common carp 2.5 Growth studies Nose (1979)
2.3 Protein accretion Ogino (1980)
European sea bass 2.6 A/E ratiosb Kaushik (1998)
Gilthead sea bream 2.6 A/E ratios Kaushik (1998)
Japanese eel 4.0 Growth studies Arai (Nose, 1979)
Japanese flounder 2.0 A/E ratios Forster and Ogata (1998) Lake trout 2.0–2.6c Growth studies Hugheset al. (1983)
Milkfish 4.0 Growth studies Borlongan and Coloso (1993)
Nile tilapia 3.1 Growth studies Santiago and Lovell (1988)
Rainbow trout 2.4 Protein accretion Ogino (1980)
Red drum 2.9 A/E ratios Moon and Gatlin (1991)
Red sea bream 2.2 A/E ratios Forster and Ogata (1998)
Turbot 2.6 A/E ratios Kaushik (1998)
White sturgeon 3.0 A/E ratios Ng and Hung (1995)
aRequirements are expressed as percentage of protein.
bSee Table 3.4, footnoteb.
cThese values were recalculated based on the calculated nitrogen content of the test diets.
3.4.4.2. Leucine Requirements
The leucine requirement values are presented in Table 3.7. The require- ments values agree quite well, ranging from 3.3 to 3.9% of protein, except for the higher values of a little more than 5% of protein reported for the Japanese eel and milkfish. In general, the estimated values based on A/E ratios [(indispensable amino acid content/total indispensable amino acid content including cysteine and tyrosine)×1000] and protein accretion are somewhat higher than those found based on growth studies.
Wilsonet al.(1980) reported that the serum free leucine level in channel catfish remained constant regardless of the dietary leucine intake. There was, however, a marked effect of dietary leucine on the serum free isoleucine and valine levels. There was about a sixfold increase in serum free isoleu- cine and valine concentrations at the 0.7% dietary leucine level compared
Table 3.7
Leucine Requirements
Fish Requirementa Based on Reference
Atlantic salmon 5.2 Ideal protein Rollin (1999)
Catla 3.7 Growth studies Ravi and Devaraj (1991)
Channel catfish 3.5 Growth studies Wilsonet al. (1980) Chinook salmon 3.9 Growth studies Chanceet al. (1964)
Chum salmon 3.8 Growth studies Akiyama and Arai (1993)
Clariashybrid 3.5 Growth studies Unprasert (1994)
Coho salmon 3.4 Growth studies Arai and Ogata (1993)
Common carp 3.3 Growth studies Nose (1979)
4.1 Protein accretion Ogino (1980)
European sea bass 4.3 A/E ratiosb Kaushik (1998)
Gilthead sea bream 4.5 A/E ratios Kaushik (1998)
Japanese eel 5.3 Growth studies Arai (Nose, 1979)
Japanese flounder 3.9 A/E ratios Forster and Ogata (1998) Lake trout 3.5–4.6c Growth studies Hugheset al. (1983)
Milkfish 5.1 Growth studies Borlongan and Coloso (1993)
Nile tilapia 2.8–3.6 Growth studies Santiago and Lovell (1988)
Rainbow trout 4.4 Protein accretion Ogino (1980)
Red drum 4.7 A/E ratios Moon and Gatlin (1991)
Red sea bream 4.2 A/E ratios Forster and Ogata (1998)
Turbot 4.6 A/E ratios Kaushik (1998)
White sturgeon 4.3 Protein accretion Ng and Hung (1995)
aRequirements are expressed as percentage of protein.
bSee Table 3.4, footnoteb.
cThese values were recalculated based on the calculated nitrogen content of the test diets.
to the 0.6% leucine level. These elevated levels of isoleucine and valine did not return to the baseline levels until a dietary level of 1.2% or above was fed. This observation was interpreted to indicate that leucine may facilitate the tissue uptake of branched-chain amino acids and/or their intracellular metabolism.
3.4.4.3. Valine Requirements
The valine requirement values of fish are presented in Table 3.8. Reason- able agreement exists among the values reported for the species studied, indicating that the requirement ranges from about 2.5 to 4% of protein.
Studies on the effect of valine intake on serum valine levels in channel cat- fish showed that they responded in a manner similar to that described for isoleucine (Wilsonet al.,1980).
Table 3.8
Valine Requirements
Fish Requirementa Based on Reference
Atlantic salmon 3.9 Ideal protein Rollin (1999)
Catla 3.6 Growth studies Ravi and Devaraj (1991)
Channel catfish 3.0 Growth studies Wilsonet al. (1980) Chinook salmon 3.2 Growth studies Chanceet al. (1964)
Chum salmon 3.0 Growth studies Akiyama and Arai (1993)
Clariashybrid 2.4 Ideal protein Unprasert (1994)
Coho salmon 2.2 Growth studies Arai and Ogata (1993)
Common carp 3.6 Growth studies Nose (1979)
2.9 Protein accretion Ogino (1980)
European sea bass 2.9 A/E ratiosb Kaushik (1998)
Gilthead sea bream 3.0 A/E ratios Kaushik (1998)
Japanese eel 4.0 Growth studies Arai (Nose, 1979)
Japanese flounder 2.5 A/E ratios Forster and Ogata (1998) Lake trout 2.6–3.3c Growth studies Hugheset al. (1983)
Milkfish 3.6 Growth studies Borlongan and Coloso (1993)
Nile tilapia 2.8 Growth studies Santiago and Lovell (1988)
Rainbow trout 3.1 Protein accretion Ogino (1980)
Red drum 3.1 A/E ratios Moon and Gatlin (1991)
Red sea bream 2.5 A/E ratios Forster and Ogata (1998)
Turbot 2.9 A/E ratios Kaushik (1998)
White sturgeon 3.3 Protein accretion Ng and Hung (1995)
aRequirements are expressed as percentage of protein.
bSee Table 3.4, footnoteb.
cThese values were recalculated based on the calculated nitrogen content of the test diets.
3.4.4.4. Interactions
Some differences appear to exist in the apparent isoleucine–leucine–
valine interactions among different fish. Chance et al. (1964) found that the isoleucine requirement in chinook salmon increased slightly with in- creasing levels of dietary leucine. This effect was not observed in either the common carp (Nose, 1979) or the channel catfish (Robinsonet al.,1984).
Nose (1979) did, however, observe reduced growth rates in carp fed high dietary isoleucine levels during a leucine requirement study. This reduced growth rate was not observed when the leucine requirement study was re- peated at a lower isoleucine level. Robinsonet al.(1984) concluded that a nutritional interrelationship does exist among the branched-chain amino acids in the channel catfish but the interaction does not appear to be as severe as has been observed in certain other animals.