热应激对山羊粪便菌群结构及代谢产物的影响OA北大核心CSTPCD

[Objective]The aim of this trial was to investigate the effects of heat stress on fecal flora structure and metabolites in goats.[Method]Six adult castrated rams of Dazu Montenegrin sheep with similar age and body weight of 28.4 kg±3.2 kg were selected,and a single factor self-control experimental design was used.They were subjected to three stages of treatment:Severe heat stress(H group,temperature and humidity index(THI)=91),moderate heat stress(M group,THI=84),and no heat stress(L group,THI=71).Each treatment stage was 15 days,and the transition period was 7 days.Rectal feces were collected at 14:00 on the last day of each stage for microbial 16S rRNA sequencing and metabolomics analysis.[Result]There was no significant difference in the diversity of goat fecal flora among the three groups(P＞0.05).Compared with group L,in H and M groups,the relative abundance of Bacteroidetes was significantly decreased(P＜0.05),and the relative abundance of Proteobacteria was significantly increased(P＜0.05).The relative abundances of Christensenaceae R-7 group,Clostridium sensu stricto 1,and Family XⅢ AD3011 group were significantly increased(P＜0.05),whereas the relative abundances of Bacteroides and unclassified_f_Lachnospiraceae were significantly decreased(P＜0.05).The contents of atrazine,cholic acid,taurocholate,oleic acid,hyperforin,and taurocholic acid in feces were significantly increased(P＜0.05),whereas the contents of Pro-Ala,Arg-Thr and homoveratric acid were significantly decreased(P＜0.05).Differential metabolites in feces under heat stress conditions were significantly enriched in the pathways of taurine and hypotaurine metabolism,ABC transporters,glutathione metabolism and gap junction(P＜0.05).[Conclusion]Heat stress led to changes in the structure of goat fecal flora,which was not conducive to goat intestinal health.It also upregulated the biosynthetic metabolic pathways of arginine and primary bile acids,which helped goats adapt to high humidity and heat environments.It also led to an increase in the content of toxic substances in goat metabolites,which might cause damage to the intestinal barrier and nervous system.