不同饵料对大口黑鲈生长性能和肠道微生物的影响

DIFFERENT DIETS ON GROWTH PERFORMANCE AND INTESTINAL BACTERIAL COMMUNITY OF LARGEMOUTH BASS(MICROPTERUS SALMOIDES)

以冰鲜鱼、配合饲料和混合投喂3种饵料,研究其对大口黑鲈(Micropterus salmoides)生长性能和肠道微生物的影响。结果表明,在生长性能方面,配合饲料组试验鱼的末均重、体长、增重率和特定生长率均显著低于冰鲜鱼组和混合投喂组(P<0.05),混合投喂组最后养成规格最大,生长速度也最快,但与冰鲜鱼组差异不显著(P>0.05)。在肠道微生物群落的丰富度与多样性方面,配合饲料投喂组丰富度最高,冰鲜鱼组最低,但冰鲜鱼组多样性最高,配合饲料投喂组次之,混合投喂组最低。在门级水平上,厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)、蓝藻门(Cyanobacteria)、拟杆菌门(Bacteroidota)、浮霉菌门(Planctomycetota)、绿弯菌门(Chloroflexi)和酸杆菌门(Acidobacteriota)是大口黑鲈肠道优势菌群。属级水平上,冰鲜鱼组的优势菌属主要为支原体属(Mycoplasma)、克雷伯氏菌属(Klebsiella)及聚球菌属(Synechococcus_CC9902);配合饲料组优势菌属为克雷伯氏菌属(Klebsiella)、罗姆布茨菌(Romboutsia)及分枝杆菌属(Mycobacterium);混合投喂组优势菌属则是支原体属(Mycoplasma)、厌氧氨氧化菌(Candidatus_Brocadia)及罗姆布茨菌(Romboutsia)。功能预测表明,配合饲料投喂组大口黑鲈肠道菌群在“能量生产与转化”“碳水化合物运输和代谢”“氨基酸转运与代谢”和“脂质转运与代谢”等功能类群的相对丰度最高,而冰鲜鱼组肠道菌群在“核苷酸的转运和代谢”“辅酶运输和代谢和翻译”“核糖体结构和生物发生”等功能类群的相对丰度占优。饵料对大口黑鲈的生长、肠道菌群组成和功能都具有显著的影响。研究为大口黑鲈的配合饲料开发和健康养殖提供了理论依据。

The frozen fish is widely used in the culture of largemouth bass Micropterus salmoides.However,feeding of frozen trash fish not only lowered conversion rates but also caused the waste of natural resources and serious environment pollution.It is an inevitable trend for the largemouth bass aquaculture industry to replace frozen trash fish with formulated feed.In the present study,the frozen fish,formulated feed and frozen fish plus formulated feed(mixed)were used to investigate their effects on growth performance and intestinal bacterial community of M.salmoides.Results showed that the formulated feed group had the lowest average final body weight,body length,weight growth rate and specific growth rate,which were significantly lower than that of the frozen fish group and the mixed group(P<0.05),but there were no significant differences between the frozen fish group and the mixed group(P>0.05).The community richness of the intestinal microbiome was the highest in formulated feed group,and the lowest in frozen fish group.On the contrary,the diversity of the intestinal microbiome was the highest in frozen fish group,and the lowest in formulated feed group.Eight phyla including Firmicutes,Proteobacteria,Actinobacteriota,Cyanobacteria,Bacteroidota,Planctomycetota,Chloroflexi and Acidobacteriota were the dominant bacterial phyla.In the genera level,Mycoplasma,Klebsiella and Synechococcus_CC9902 were the dominant genera in the frozen fish group,while Klebsiella,Romboutsia and Mycobacterium,Mycoplasma,Candidatus_Brocadia and Romboutsia were the dominant genera in the formulated feed group and the mixed group respectively.Functional prediction showed that the abundance of functional genes involved in“energy production and conversion”“carbohydrate transport and metabolism”“amino acid transport and metabolism”and“lipid transport and metabolism”were dominant in the formulated feed group.Meanwhile,the abundance of functional genes involved in“nucleotide transport and metabolism”“coenzyme transport and metabolism”and“translation,ribosomal structure and biogenesis”were dominant in the frozen fish group.The results suggested that different diets significantly affected growth performance,the composition and functions of intestinal microflora.Furthermore,the present study provided scientific data for healthy cultivation and formulated feed innovation of M.salmoides.