蛋白水平对F_2代斑节对虾幼虾生长及消化酶活力的影响

Effects of dietary protein content on growth performance and digestive emzyme activities of F_2 generation Penaeus monodon

研究了饲料蛋白水平对F2代（针对饲料蛋白水平选育）斑节对虾幼虾生长和消化酶活力的影响.试验设计7个饲料蛋白质水平组（34％、36％、38％、40％、42％、44％、46％）,对选育F2代斑节对虾幼虾（2.84±0.04 g）进行48 d养殖.结果表明,F2代斑节对虾幼虾在38％饲料蛋白组的增重率和特定生长率均为最高,且饵料系数最低;在34％饲料蛋白组蛋白质效率最高,与36％、38％饲料蛋白组无显著差异,但显著高于40％及以上的各饲料蛋白水平组;成活率表现为低蛋白组（34％～42％）显著高于高蛋白组（44％、46％）.斑节对虾常规营养成分受饲料蛋白水平影响,全虾粗蛋白含量随着饲料蛋白水平的升高呈现出上升趋势,但肌肉中各组的粗蛋白含量无显著差异;全虾粗脂肪含量随着饲料蛋白水平的升高呈现下降的趋势.胃蛋白酶表现为34％饲料蛋白组最高,随着蛋白质含量的升高而呈现出先上升后下降再上升的波动,与肝脏蛋白酶的含量显示为波动互补的趋势;胃中淀粉酶的含量均高于肝脏,但胃淀粉酶在各组间无显著差异;胃和肝脏脂肪酶随着蛋白含量的升高总体表现为下降的趋势.综合生长数据、常规营养成分和消化酶活力等指标得出,38％饲料蛋白水平较为适宜选育F2代斑节对虾幼虾生长,针对低蛋白水平饲料的选育是有效的.

Effects of seven dietary protein contents （34%, 36%, 38%, 40%, 42%, 44%, 46%） on growth performance and digestive emzyme activities of domestic F2 generation Penaeus monodon were studied under laboratory condition. P. monodon （2.84±0.04 g） were fed with the seven diets in triplicate for 48 d. The results showed that shrimp fed with 38% dietary protein achieved the highest weight growth rate （WG） and special growth rate （SGR） and the lowest FCR. P. rnonodon fed with 34% dietary protein achieved the highest protein efficiency ratiol （PER）, without statistical differences with that fed with 36%, 38% dietary protein, significantly higher than shrimp fed with 40% and above dietary protein. Survival rate of low-protein group （34%-42%） was significantly higher than that of high-protein group （44%, 46%）. Dietary protein content also affected the whole body composition of P. rnonodon. Body crude protein content increased, while body crude fat content decreased with dietary protein level increasing, but there was no statistical difference of muscle crude protein in each group. Pepsin of shrimp fed with 34% dietary protein was the highest, with the increase of protein content, it increased first, then decreased, and then increased again, showed fluctuation and complementary trend with liver protease content. Amylase in stomach was higher than that in hepatopancreas, but without statistical differences with stomach amylase in each group. Lipase in stomach and hepatopancreas showed a downward trend with protein content increasing. The growth performance and digestive enzyme activities indicated that the effect of feed with low protein level on domesticated F2 generation P. monodon growth was favorable, suggesting that dietary protein of 38% was more appropriate.