Effects of Dietary Protein Level on Growth Performance, Body Composition and Digestive Enzyme Activities of Juvenile Nibea albiflora
This experiment was conducted to investigate the effects of dietary protein level on growth perform-ance, body composition and digestive enzyme activities of juvenile Nibea albiflora. Fish meal, soybean meal and wheat gluten meal were used as main dietary protein sources to formulate isoenergetic and isolipidic diets at six protein levels, which were 37.52%, 41.80%, 46.52%, 49.84%, 56.80% and 61.48%, respectively. A total of 360 juvenile Nibea albiflora with the average body weight of (17.84±0.34) g were randomly allocated into 6 groups with 3 replicates per group and 20 juvenile Nibea albiflora per replicate, and they were reared in 500 L water-flowing glass fiber reinforced plastic buckets, separately. An 8-week growth experiment was con-ducted under the condition of water temperature (27±2) ℃ and salinity 28 to 29. The results showed that the weight gain rate, specific growth rate and feed conversion rate of the juvenile Nibea albiflora in the 56. 80%group were significantly higher than those in the other groups except 61.48% group ( P<0.05) . With the dieta-ry protein level increasing, there were no significant changes in hepatosomatic index, viscerasomatic index and condition factor of juvenile Nibea albiflora. Dietary protein level had no significant influences on the contents of crude protein, crude lipid and ash in the body of juvenile Nibea albiflora ( P>0.05) . The intestinal protease ac-tivity of juvenile Nibea albiflora increased at first and then decreased with the dietary protein level increasing. Dietary protein level had no significant influences on the activities of intestinal amylase, lipase as well as prote-ase, amylase and lipase in the liver ( P>0.05) . With specific growth rate as an evaluating index, the optimal dietary protein requirement estimated by broken-line model is 55. 39% for juvenile Nibea albiflora.
国家科技期刊平台
NSTL
万方数据
维普
