鱼肽和蛋白酶替代部分鱼粉对凡纳滨对虾生长、消化酶及肠道菌群的影响

Effects of partial fish meal substitution by fish peptide and protease on growth,intestinal digestive enzymes and intestinal microflora of Pacific white shrimp Litopenaeus vannamei

为研究用鱼肽与蛋白酶替代饲料中5%的鱼粉后对凡纳滨对虾Litopenaeus vannamei生长的影响,以体质量为(0.32±0.01)g的对虾苗为试验对象,试验设置鱼肽组、蛋白酶组和对照组,分别投喂基础饲料中添加5%的鱼肽、0.3%的蛋白酶和基础饲料(均为质量分数),每组设3个平行,每个平行放40尾虾,共养殖56 d,试验结束后测定虾的生长性能、消化指标和肠道菌群丰度。结果表明:鱼肽、蛋白酶组凡纳滨对虾的终末体质量和增重率显著高于对照组(P<0.05),各组间肝体比和含肉率有显著性差异(P<0.05),但各组间其他生长性能指标无显著性差异(P>0.05);与对照组相比,鱼肽、蛋白酶组血清中葡萄糖(GLU)、总胆固醇(T-CHO)、甘油三酯(TG)含量显著降低(P<0.05),而肠道脂肪酶、胃蛋白酶活性显著提高(P<0.05);与对照组相比,鱼肽、蛋白酶组Shannon指数显著提高(P<0.05),而Simpson指数显著降低(P<0.05);在门水平上,鱼肽组的变形菌门Proteobacteria和放线菌门Actinobacteria丰度高于对照、蛋白酶组;在纲水平上,鱼肽、蛋白酶组的放线菌纲Actinobacteria和γ变形菌纲Gammaproteobacteria丰度高于对照组;在属水平上,鱼肽、蛋白酶组未分类的红杆菌属Rhodobacteraceae_unclassified丰度高于对照组且差异较大,各组间未分类的黄杆菌属Flavobacteriaceae_unclassified丰度差异不大。研究表明,饲料中添加适量的鱼肽和蛋白酶可提高凡纳滨对虾的生长性能,对消化指标及肠道结构有积极影响,二者均可作为新资源替代对虾配合饲料中5%的鱼粉。

In order to reveal that enzymatic peptide and protease replace 5%fish meal in the diet of Pacific white shrimp Litopenaeus vannamei,the effects of partial fish meal substitution by enzymatic peptide and protease on the growth,digestive indices and intestinal flora of Pacific white shrimp was investigated.Pacific white shrimp juveniles with initial body weight of(0.32±0.01)g were reared in an aquarium(40 cm×50 cm×60 cm)and fed basic diet(control group),and diet containing 5%fish meal replaced by 5%peptide(group EP)and by 0.3%protease(group PR)at water temperature of 28℃for 56 d with three repetitions.The results showed that there were higher final body weight and weight gain rate in the shrimp in EP and PR groups than those in the control group,with significant differences in hepato-somatic ratio and dressing rate(P<0.05).The plasma glucose,total cholesterol and triglyceride levels were shown to be significantly higher in EP and PR groups than those in control group(P<0.05).The shrimp in EP and PR groups had higher activities of lipase,pepsin and protease than the shrimp in control group did(P<0.05).Shannon index in enzymatic peptide and protease groups was higher than that in control group,Simpson index in protease group was significantly lower than that in control group,and that in peptide group was significantly lower than that in protease group(P<0.05).At the phylum level,the number of Proteobacteria and Actinobacteria in group enzymatic peptide was higher than that in control group and protease group.At the class level,in enzymatic peptide and protease groups the Alphaproteobacteria of Proteus was lower than that in control group,and Gammaproteobacteria in enzymatic peptide and protease groups were higher than in control group and enzymatic peptide group,and Verrucomicrobiae was higher than in control group and protease group.At the genus level,it can be seen that the proportion of Rhodobacteraceae_unclassified in enzymatic peptide and protease groups was higher than that in the control group,with the large difference,and little difference among Flavobacterium_unclassified groups.The findings indicated that the addition of enzymatic peptide and protease in the diet improved the growth performance of Pacific white shrimp,with positive impact on digestive indices and intestinal structure,and that enzymatic peptide and protease were used as a new resource to reduce the addition of fish meal in shrimp formula feed.