Sur l'utilisation du self feeder comme outil d'epreuve nutritionnelle du loup, Dicentrarchus labrax — Résultats préliminaires avec la méthionine

Abstract

Five different diets were offered simultaneously to each of three different groups of fish under self feeding conditions. Diets differed only in methionine content (0.30, 0.65, 1.00, 1.35 and 1.70% of diet). Fish groups differed in weight (group A, 0.2 g; group B, 2.0 g; group C, 200 g mean weight). Measure of food demand showed that group A refused feeding and declined in vitality and health; group B showed a net preference for 1.35% methionine (considered as optimum); group C was more influenced by spatial preferences. In a second experimental period, the following modifications were introduced: commercial food for sea bass (Aqualim dry pellet) was offered to group A in addition to the five initial diets; for groups B and C changes in spatial distribution of self feeders were introduced. The fish in group A reacted instantly to the introduction of the commercial food which they ate preferentially. Fish of groups B and C maintained behaviour similar to that of the previous period. The authors conclude that sea bass can detect and discriminate small doses of methionine, showing preferences easily demonstrable with the self-feeding method.