饲料添加怀山药对鲤生长、肠屏障及肠道菌群的影响

Effects of Chinese Yam on Growth,Gut Defense Barrier and Intestinal Microflora of Common Carp(Cyprinus carpio L.)

为研究饲料添加怀山药对鲤生长、肠屏障及肠道菌群的影响,本试验在基础饲粮中分别添加0(对照)、1%和2%的怀山药,选择健康状况良好的180尾鲤[(75.25±1.45)g],随机分为3组,每组3个重复。饲养8周后检测其生长性能、肠道酶活性、肠组织形态、肠道防御屏障相关基因表达以及肠道内容物短链脂肪酸(SCFAs)含量和肠道菌群的变化。结果显示:1)与对照组相比,添加怀山药对鲤生长性能无显著影响(P>0.05),但可以增加肠微绒毛密度和完整性,增加杯状细胞数量、肠道黏膜褶皱数量和肠绒毛高度,从而改善鲤肠道组织结构,提高吸收表面积。2)与对照组相比,怀山药组肠道组织过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性增强(P>0.05),白细胞介素-1β(IL-1β)基因相对表达量显著升高(P<0.05),转化生长因子-β(TGF-β)、闭合蛋白(Occludin)、紧密连接蛋白-1(ZO-1)和Toll样受体4(TLR4)基因相对表达量也显著上调(P<0.05)。3)肠道菌群高通量测序结果表明,在门水平上,梭杆菌门、变形菌门和拟杆菌门是鲤肠道的优势类群。与对照组相比,怀山药组梭杆菌门相对丰度显著增加(P<0.05),而变形菌门相对丰度显著下降(P<0.05);在属水平上,与对照组相比,怀山药组肠道鲸杆菌属相对丰度显著增加(P<0.05),而气单胞菌属相对丰度显著下降(P<0.05)。4)与对照组相比,添加怀山药后,肠道内容物乙酸和SCFAs的含量显著升高(P<0.05)。综上所述,饲粮中添加怀山药可以改善鲤肠道菌群组成结构、增强肠上皮防御屏障、提升机体免疫力,可作为一种潜在开发的免疫刺激剂应用于水产养殖。

To explore the effects of Chinese yam on growth,gut defense barrier and the intestinal microbiota of the common carp(Cyprinus carpio L.),a total of 180 carps with uniform individuals[(75.25±1.45)g]were allocated into 3 groups with 3 replicates of 20 fishes each,and fed a basal diet supplemented with 0(control),1%and 2%Chinese yam for 8 weeks.The changes of growth performance,intestinal enzyme activity,intestinal tissue morphology,intestinal defense barrier related gene expression,intestinal short chain fatty acids(SCFAs)content and intestinal microflora were detected.Results showed as follows:1)compared with the control group,the growth performance was not affected after adding the Chinese yam(P>0.05),but the intestinal villus density,number of goblet cells,number of intestinal mucosa folds and the height of intestinal villus in the treated groups increased,so as to improve the intestinal tissue structure and increase the absorption surface area.2)Compared with the control group,the activities of catalase(CAT)and superoxide dismutase(SOD)were enhanced with the Chinese yam supplementation(P>0.05).The relative expression level of interleukin-1β(IL-1β)gene was significantly increased(P<0.05),and the relative expression levels of transforming growth factor-β(TGF-β),Occludin,tight junction protein-1(ZO-1)and Toll-like receptor 4(TLR4)genes were also significantly up-regulated(P<0.05).3)High throughput sequencing results revealed that the bacteria Fusobacteria,Proteobacteria and Bacteroidetes were the most abundant microbial community at the phylum level in the gut of the common carp.Compared with the control group,the abundance of Fusobacteria obviously increased(P<0.05),but the abundance of Proteobacteria decreased significantly in the Chinese yam treated groups(P<0.05).Also,at the genus level,the relative abundance of Cetobacterium significantly increased(P<0.05),accompanied with the relative abundance of Aeromonas significantly reduced after adding Chinese yam in the feed(P<0.05).4)Compared with the control group,the contents of acetic acid and total SCFAs in the intestine of the common carp were also significantly increased(P<0.05)in the Chinese yam treated groups.These results suggest that Chinese yam supplemented feed can improve the immunity of the common carp by modulating the intestinal microflora and increase the gut defense barrier,and can be used as an immune-stimulating additive in aquaculture.