丁酸梭菌对花鲈幼鱼生长性能、免疫消化及肠道菌群的影响OA北大核心CSTPCD

[Objective]This experiment was performed to investigate the effects of dietary Clostridium butyricum on growth performance,digestion,immunity,antioxidant capacity and intestinal microbiota of juvenile Lateolabrax macula-tus,and provide a theoretical basis for the application of C.butyricum in the culture of L.maculatus.[Method]Juvenile L.maculatus was used as experiment material.Juvenile L.maculatus had been fed for 56 d with six diets containing 0(D0,control),0.25%(D1),0.50%(D2),1.00%(D3),2.00%(D4)and 4.00%(D5)C.butyricum.The growth performance,intestinal digestive enzyme activity,serum biochemical and immune indicators,and intestinal morphology indicators of juvenile L.maculatus were measured,and the composition of intestinal microbiota was analyzed.[Result]The dietary C.butyricum could significantly reduce the feed coefficient(P<0.05,the same below),significantly improved final mean body weight of L.maculates,the weight gain rate(WGR),and specific growth rate(SGR)in D3,D4 and D5 groups were significantly higher than the D0 group.Compared with D0 group,the activities of intestinal chymotrypsin,lipase were significantly increased in D4 group,while the contents of serum total cholesterol and triglyceride and the activities of glutamic oxalacetic transaminase and glutamic-pyruvic transaminase were significantly decreased.The activities of ly-sozyme,alkaline phosphatase and total nitric oxide synthase in D4 group were significantly higher than those in D0 group,and the activities of phenoloxidase in D3 group were significantly higher than those in D0 group.Compared with D0 group,the catalase activity and total antioxidant capacity in D3 and D5 groups were significantly increased,the super-oxide dismutase activity in D4 group was significantly increased,and the malondialdehyde content was significantly de-creased.The intestinal muscle thickness and villus height in D2,D3 and D5 groups were significantly higher than those in D0 group.The OTU number and Chao1 index of the intestinal microflora of juvenile L.maculatus in D3 group were sig-nificantly higher than those in D0 group,and the Simpson index and Shannon index of the intestinal microflora in all test groups were significantly higher than those in D0 group.At the phylum level,C.butyricum reduced the relative abun-dance of Proteobacteria and Firmicutes.The relative abundance of Actinobacteriota,Planctomycetota,Acidobacteriota,Chloroflexi,Bacteroidota and Gemmatimonadota increased.At the genus level,C.butyricum decreased the relative abun-dance of harmful bacteria like Ralstonia,Enterovibrio and Vibrio,and increased the relative abundance of beneficial bac-teria like Arthrobacter and KD4-96_unclassified.[Conclusion]Adding C.butyricum in the dietary can significantly im-prove the growth performance,improve the digestion,immunity and antioxidant capacity of juvenile L.maculatus,regu-late the structure and relative abundance and improve the diversity of intestinal microbiota of juvenile L.maculatus.The best effect is to add 2.00%of C.butyricum to the dietary.