Kinetic investigations on the behaviour of free amino acids in the plasma and of two aminotransferases in the liver of rainbow trout ( Salmo gairdnerii Richardson) after feeding on a synthetic composition containing pure amino acids

Abstract

1. 1. Growing rainbow trout were fed at 8 a.m. daily with a composition conforming with their requirements. 2. 2. The free amino acids in the plasma exhibit no uniform behaviour after feeding. The concentrations of the indispensable amino acids rise. The dispensable amino acids behave indifferently. The aspartate and glutamate concentrations are also high 3 and 12 hr after feeding with pure amino acids, their variability also rising to 80–100% of their mean values. 3. 3. The GOT reaches its maximum activity 6 hr after feeding; the GPT does not change. The amount of soluble protein in the liver fluctuates after feeding. 4. 4. When comparing fish and mammals, the behaviour of the dispensable amino acids in the former may be ascribable to their relatively high amino acid requirement. However, the behaviour of the GOT and the soluble proteins in the liver appears to follow a rhythmic activity pattern.