摘要Nutritional diarrhea and subsequent performance degradation in weaned piglets are major challenges for the pig industry.Bile acids (BA) can be added to the diet as emulsifiers.This experiment was conducted to investigate the effects of chenodeoxycholic acid (CDCA),a major primary BA,on growth performance,serum metabolic profiles and gut health in weaned piglets.A total of 72 healthy weaned piglets were randomly assigned to the control (CON) and the CDCA groups,which were feed a basal diet and the basal diet supplemented with 200 mg/kg CDCA for 30 d,respectively.Our results demonstrated that CDCA significantly increased final BW and average daily gain (ADG),decreased feed-to-gain (F:G) ratio and tended to reduce diarrhea incidence.In addition,CDCA increased the villus height-to-crypt depth (V:C)ratio,elevated goblet cell numbers and the expression of tight junction proteins,suggesting the enhancement of intestinal barrier function.As an emulsifier,CDCA increased jejunal lipase activity and the mRNA expression of pancreatic lipases.CDCA supplementation also altered the serum metabolic profiles,including increasing the levels of indole 3-acetic acid,N'-formylkynurenine and theobromine that were beneficial for gut health.Moreover,the relative abundance of 2 beneficial gut bacteria,Pre-votella 9 and Prevotellaceae TCG-001,were increased,whereas the relative abundance of a harmful bacteria,Dorea,was decreased in the gut of weaned piglets supplemented with CDCA.Importantly,the altered serum metabolic profiles showed a strong correlation with the changed gut bacteria.In conclusion,CDCA improved the growth performance of weaned piglets by improving intestinal morphology and barrier function,and enhancing lipid digestion,accompanied by alterations of serum metabolic profiles,and changes in relative abundance of certain gut bacteria.