Variation de la concentration des acides amines libres du plasma au cours du cycle reproducteur chez le manchot empereur, aptenodytes forsteri

Abstract

1. 1. Nine amino acids, alanine, serine, arginine, threonine, lysine, valine, glutamic acid, α-amino butyric acid and leucine, together represent 75–85 per cent of the total plasma amino acids in the emperor penguin; alanine itself represents one-third (100 μM/100 ml). 2. 2. A 40 per cent increase of total amino acids, especially branched (val, leu, ile), basic (lys, his, methyl-3-his) amino acids and methionine, was observed in males at the end of incubation (90–120 days fasting) or in animals undergoing severe starvation experimentally, except in those at the end of moulting. This could be attributed to high muscle proteolysis after lipid storage consumption. 3. 3. During egg formation an increase of plasma amino acids, mainly serine, was seen in females (330–440 μM/100 ml). 4. 4. At the beginning of moulting, during synthesis of the new feathers, plasma-free amino acid concentration increased from 310 to 510 μM/100 ml. The levels of basic (arg, lys, his), branched (leu, ile) amino acids, methionine, serine and glycine were particularly high. 5. 5. The total amino acids of fasting baby penguins, 4–6 months old, is normally similar to that of adults but is clearly higher in the postabsorptive state. 6. 6. Variations in total plasma amino acids of the emperor penguin seem to be correlated with the level and nature of metabolism, that is with breeding and moulting, rather than with fasting itself.