Effects of Mulberry Leaf Oligosaccharides on Growth Performance,Intestinal Digestive Enzyme Activity,Immune Function and Microflora of Largemouth Bass(Micropterus salmoides)
This experiment was conducted to investigate the effects of mulberry leaf oligosaccharides(MLO)supplementation on growth performance,intestinal digestive enzyme activity,immune function and microflora of largemouth bass(Micropterus salmoides).A total of 450 largemouth bass with an average initial body weight of(26.89±1.16)g were randomly divided into 3 groups with 3 replicates per group and 50 bass per replicate.The control group was fed a basal diet,and the experimental groups were fed experimental diets sup-plemented with 0.5％and 1.0％MLO in the basal diet,respectively.The experiment lasted for 80 days.The results showed as follows:1)compared with the control group,the feed coefficient(FCR)and viscerosomatic index(VSI)of largemouth bass in experimental groups were significantly decreased(P＜0.05),and the hepa-tosomatic index(HSI)in 1.0％MLO group was significantly decreased(P＜0.05).2)Compared with the control group,the intestinal α-amylase,lipase and trypsin activities of largemouth bass in experimental groups were significantly increased(P＜0.05),but there were no significant differences in intestinal villus height,vil-lus width and muscular thickness in experimental groups(P＞0.05).3)Compared with the control group,the Sobs index,ACE index and Chao1 index of intestinal microflora of largemouth bass in experimental groups were significantly decreased(P＜0.05);the Simpson index in 0.5％MLO group was significantly higher than that in the control group and 1.0％MLO group(P＜0.05).At the phylum level,compared with the control group,the Firmicutes relative abundance in intestinal microflora of largemouth bass in experimental groups was significantly decreased(P＜0.05),the relative abundances of Proteobacteria,Fusobacteriota and Bacteroidota were significantly increased(P＜0.05),and the Firmicutes to Bacteroidota ratio was significantly increased(P＜0.05).At the genus level,compared with the control group,the Mycoplasma relative abundance in intes-tinal microflora in experimental groups was significantly decreased(P＜0.05),while the relative abundances of Acinetobacter,Lactobacillus and Bacillus were significantly increased(P＜0.05).4)Compared with the con-trol group,the mRNA relative expression levels of intestinal interleukin-8(IL-8),nuclear factor-κB(NF-κB)and tumor necrosis factor-α(TNF-α)of largemouth bass in experimental groups were significantly decreased(P＜0.05),while the mRNA relative expression levels of intestinal interleukin-10(IL-10)and transforming growth factor-β(TGF-β)were significantly increased(P＜0.05).In conclusion,MLO supplementation can reduce FCR,VSI and HSI,improve intestinal digestive enzyme activity,regulate intestinal microflora,im-prove the relative abundances of intestinal probiotics,and enhance the immune function of largemouth bass(Micropterus salmoides).[Chinese Journal of Animal Nutrition,2024,36(3):1795-1805]
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维普
