摘要
Dissolved oxygen(DO)is one of most important factors which affect wide range physiologic features of including immune responses and intestinal bacterial community.However,the underlying mechanisms remain enigmatic.To address this question,the intestinal bacterial community compositions and the immune features of Atlantic salmon(Salmo salar)grown in recirculating aquaculture systems(RAS)were characterized.Fish were reared under different DO saturation levels,e.g.,200% saturation named high group(H),100%saturation named control group(CK),and 60%saturation named lower group(L).Large variations in the operational taxonomic units(OTUs)frequency distribution for the intestinal bacterial community of Atlantic salmon were observed.The intestinal bacterial community of all groups was dominated mainly by three phyla,e.g.,Proteobacteria.Firmicutes,and Bacteroidetes.Interestingly,Acinetobacter baumannii,an opportunistic pathogen of salmon was increased significantly in L group.We further monitored the immunity features of fish under different DO levels.The results show that leucocyte number,cortisol level,the expressions of interleukin-1β(IL-1β),Toll-like receptor 4(TLR4),and nucleotide-binding oligomerization domain like protein 2(NOD2)were higher at significant levels in the L group than those in the other two groups.TLR4 and NOD2 are usually related with the bacterial infections;therefore,it is reasonable to believe that the stronger immune responses observed in the L group might be related with the higher abundance of A.baumannii in the inte stine of Atlantic salmon.Overall,these findings demonstrated that low DO level may induce stronger immunity responses in Atlantic salmon.
基金
Supported by the Shandong Province Key Research and Invention Program(No.2017CXGC010K)
the China Agriculture Research System(No.CARS-47)
the National Key Research and Development Program(No.2018YFD0901204)
the National Infrastructure of Fishery Germplasm Resource(No.2019DKA30470)
the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0502-2)
the National Natural Science Foundation of China(Nos.31872606,31572657,U1701233,31402283,31802319)
the Department of Agriculture and Rural Areas of Guangdong Province(No.KA1911101)
the Natural Science Foundation of Shandong Province(No.ZR2018BC053)
the Agricultural Application Technology Innovation Project of Shandong Province in 2018/2019(No.SD2019YY011)
the Shandong Province Major Scientific and Technological Innovation Projects(No.2019JZZY020710)。