Dietary silymarin improves performance by altering hepatic lipid metabolism and intestinal microbiota function and its metabolites in late laying hens

Abstract Background Liver lipid dysregulation in late laying hens is one of the most major factors resulting in performance production decline. The present study was conducted to evaluate the effects of silymarin (SIL) on performance, liver lipid metabolism, cecal microbiota and its metabolites in late laying hens. Results A total of 480 sixty-eight weeks Roman Pink layers were randomly assigned to 5 groups: control group fed with basal diet (CON), experimental groups fed the basal diet with 250, 500, 750 or 1,000 mg/kg silymarin (SIL250, SIL500, SIL750, and SIL1000, respectively). Results showed that there was a quadratic increase in laying rate ( P 0.05). The average egg weight of SIL500 and SIL750 group were higher than CON group during 5 to 8 weeks ( P < 0.05). Compared with CON group, average daily feed intake of hens during the whole period in SIL750 group was significantly higher and feed-egg ratio in SIL500 group from 5 to 8 weeks was significantly decreased ( P < 0.05). Additionally, shell strength at week 4 and thickness at week 8 increased quadratically ( P < 0.05) in response to the increasing addition of SIL at week 4( P < 0.05.) SIL500 group significantly decreased the serum ALT and AST activity compared with CON group ( P < 0.05). Serum triglycerides, total cholesterol levels decreased quadratically ( P < 0.05) in response to the increasing addition of SIL at week 12. Moreover, the SIL groups significantly regulated the expression of FASN, ACC, Apo-VLDLⅡ, FXR, CYP7A1 in liver ( P < 0.05). Furthermore, dietary SIL supplementation altered the cecal microbiological structure and three species of phocaeicola were dominated microbial functions which were enriched in secondary bile acid synthesis. Targeted metabolomics analyses revealed 9 metabolites that were significantly different that enriched in Thiamin metabolism and the ATP-binding cassette transporters ( P < 0.05). Conclusions Dietary silymarin improves performance by altering hepatic lipid metabolism and intestinal microbiota function and metabolites in late laying hens.