饲料中添加发酵蚕沙对草鱼生长、消化、免疫及炎症反应的影响

Effects of Dietary Fermented Silkworm Excrement on Growth,Digestive,Immune and Inflammation of Grass Carp(Ctenopharyngodon idella)

本试验旨在研究饲料中添加发酵蚕沙对草鱼(Ctenopharyngodon idella)生长、消化、免疫及炎症反应的影响。试验挑选240尾初始均重为(44.51±0.42)g的草鱼幼鱼,随机分为5组,每组3个重复,每个重复16尾鱼。各组分别投喂发酵蚕沙添加水平为0(对照组)、5%、10%、15%和20%的试验饲料。试验期8周。结果表明:1)15%和20%发酵蚕沙组的终末均重、增重率、特定生长率显著低于对照组(P<0.05),饲料系数显著高于对照组(P<0.05)。2)10%、15%和20%发酵蚕沙组的肝体比和脏体比显著低于对照组(P<0.05),15%和20%发酵蚕沙组的肠体比显著高于对照组(P<0.05)。3)10%、15%和20%发酵蚕沙组的鱼体粗蛋白质含量显著高于对照组(P<0.05),20%发酵蚕沙组的鱼体粗灰分含量显著高于对照组(P<0.05)。4)对照组的肠道脂肪酶和胰蛋白酶活性显著高于其他各组(P<0.05)。5)15%发酵蚕沙组的血清补体3和免疫球蛋白M含量显著高于其他组(P<0.05);20%发酵蚕沙组的血清谷丙转氨酶活性显著低于对照组(P<0.05),血清溶菌酶活性显著高于对照组(P<0.05);10%、15%和20%发酵蚕沙组的血清丙二醛含量显著低于对照组(P<0.05)。6)15%、20%发酵蚕沙组的肠道肿瘤坏死因子-α的mRNA相对表达量高于对照组(P<0.05)。由此可见,饲料中添加10%以内的发酵蚕沙不影响草鱼的生长性能;发酵蚕沙在一定程度上可以提高草鱼的非特异性免疫水平;发酵蚕沙添加水平达15%以上时,草鱼生长性能和消化能力下降,肠道炎症的风险提高。因此,草鱼饲料中发酵蚕沙添加水平应控制在10%以内,以特定生长率为依据的回归分析表明,草鱼饲料中发酵蚕沙适宜添加水平为8.65%。

This experiment was conducted to study the effects of dietary fermented silkworm excrement on growth,digestive,immune and inflammation of grass carp(Ctenopharyngodon idella).A total of 240 juvenile grass carp with initial average weight of(44.51±0.42)g were randomly divided into 5 groups with 3 replicates per group and 16 fish per replicate.Fish in 5 groups were fed experimental diets which the fermented silkworm excrement supplemental levels of 0(control group),5%,10%,15%and 20%,respectively.The experiment lasted for 8 weeks.The results showed as follows:1)the final body weight,weight gain rate and specific growth rate of 15%and 20%fermented silkworm excrement groups were significantly lower than those of the control group(P<0.05),and the feed conversion rate was significantly higher than that of the control group(P<0.05).2)The hepatosomatic index and viscerasomatic index of 10%,15%and 20%fermented silkworm excrement groups were significantly lower than those of the control group(P<0.05),and the intestine weight index of 15%and 20%fermented silkworm excrement group was significantly higher than that of the control group(P<0.05).3)The body crude protein content of 10%,15%and 20%fermented silkworm excrement groups was significantly higher than that of the control group(P<0.05),and the body crude ash content of 20%fermented silkworm excrement group was significantly higher than that of the control group(P<0.05).4)The activities of lipase and trypsin in intestine of the control group were significantly higher than those of other groups(P<0.05).5)The contents of complement 3 and immunoglobulin M in serum of 15%fermented silkworm excrement group were significantly higher than those of other groups(P<0.05);the serum alanine aminotransferase activity of 20%fermented silkworm excrement group was significantly lower than that of the control group(P<0.05),and the serum lysozyme activity was significantly higher than that of the control group(P<0.05);the serum malondialdehyde(MDA)content of 10%,15%and 20%fermented silkworm excrement groups was significantly lower than that of the control group(P<0.05).6)The mRNA relative expression level of tumor necrosis factor-αin intestine of 15%and 20%fermented silkworm excrement groups was significantly higher than that of the control group(P<0.05).To sum up,the addition of fermented silkworm excrement within 10%in the diet dose not affect the growth performance of grass carp;fermented silkworm excrement can improve the non-specific immunity level of grass carp to a certain extent;when the supplemental level of fermented silkworm excrement is more than 15%,the growth performance and digestion of grass carp reduces,and the risk of intestinal inflammation increases.Therefore,the dietary fermented silkworm excrement supplemental level of grass carp should be controlled within 10%,and the regression analysis based on specific growth rate shows that the dietary fermented silkworm excrement suitable supplemental level of grass carp is 8.65%.