Abstract:
In order to investigate optimum dietary protein requirement, juvenile mangrove red snapper Lutjanus argentimaculatus (body weight 8.0±0.3 g) were reared in seawater tanks (125 liters each) and fed one of the experimental diets at a daily ration of 2% body weight for 90 days. Six isoenergetic (22.4 kJg-1) diets were formulated to contain protein levels of 20%, 25%, 30%, 35%, 40% and 45%. Fish fed diets of 40% and 45% protein produced higher weight gain and growth rate than those of the other diets. Broken line regression analysis yielded an optimal protein level of 42.8%. Fish whole body, muscle, liver and visceral composition showed that moisture content of fish fed diets of 40% and 45% protein was significantly higher than that of fish fed diets containing protein levels of 20% to 35% in 5% increments, although the lipid contents were lower. No significant difference was observed in protein and ash contents of whole fish or body organs for the diets of 20% to 45% protein. Fish fed 40% and 45% protein diets showed higher nitrogen gain and nitrogen retention efficiency than those fed on other diets. The mesenteric fat, hepato- and viscerosomatic indices of fish fed diets of 40% and 45% protein were significantly higher than those of fish fed diets of 20%, 25%, 30% and 35% protein. Based on the biological data, it was estimated that the optimal level of protein for L. argentimaculatus weighing between 8.0 g and 110 g was 40% to 42.8%.
Page(s):
469-480
DOI:
DOI not available
Published:
Journal: Pakistan Journal of Zoology, Volume: 44, Issue: 2, Year: 2012