Energy and protein requirements of yellowtail during winter season

This study was conducted to determine the energy and protein requirements o f yellowtail during the winter season (12.8-16.5 degrees C) when they have a comparatively low feeding activity. The feeding experiment was conducted in net cages (3 x 3 x 3 m) located at Mie Prefecture, japan. The fish (745- 758 g) were split into six groups: the first five were fed to satiation, an d at 70, 50, 30, and 10% of satiation levels, respectively, while the sixth group was starved. The experimental diets were commercial soft-dry pellets (SDP) with known digestible energy (DE) and protein (DP) values. The group s were fed three times a week for 4 weeks. The growth rate was highest in t he satiation group and decreased with decreasing feeding levels. The DE and DP requirements were 42.1 kcal and 3.3g/kg BW/day for maximum growth and 1 4.7 kcal and 1.1 g/kg BW/day for maintenance of body weight. The DE and DP requirements for the maintenance of body energy content were estimated to b e 19.6 kcal and 1.5 g/kg BW/day, respectively.