Bile Acid Supplementation Reduced Hepatic Lipid Deposition and Modulated Bile Acid Metabolism and the Gut Microbiota in Weaned Piglets.

BACKGROUND

Early weaning may induce significant oxidative stress in piglets, potentially leading to hepatic lipid deposition and adversely affecting both metabolic health and growth.

OBJECTIVES

This study aimed to investigate the effect of bile acids (BA) supplementation on hepatic lipid metabolism in weaned piglets.

METHOD: Sixty-four 21-d-old weaned piglets [Duroc × (Landrace × Yorkshire); 8.21 ± 0.20 kg body weight] were randomly divided into 2 groups (8 pens per group, 2 castrated males and 2 females per pen). Piglets received either a control diet (CON) or CON supplemented with 500 mg BA per kilogram of diet (BA) for 14 d. Growth performance, hepatic lipid metabolism-related gene and protein expression, BA profiles in the liver and ileum, and ileal microbiota (16S ribosomal ribonucleic acid sequencing) were determined. Data were analyzed using 2-tailed unpaired t-tests and Kruskal-Wallis tests.

RESULTS

Compared to the CON group, the BA group showed significant reductions in serum triglycerides (TG), serum total cholesterol, and hepatic TG (49.2%, 45.7%, and 40.7%, respectively; P < 0.05), alongside a 69.9% increase in serum high-density lipoprotein cholesterol (P < 0.05). BA supplementation significantly downregulated hepatic lipogenesis-related genes and proteins but upregulated lipolysis-related genes (P < 0.05). Hepatic lipidomics showed that BA supplementation increased phosphatidylcholine (83.0%), whereas reducing triacylglycerols (84.9%), sphingomyelins (54.7%), and diacylglycerols (73.2%) (P < 0.05). BA supplementation significantly increased hepatic conjugated BA (54.2%), cholic acid (162%), chenodeoxycholic acid (270%), and the hepatic expression of farnesoid X receptor (57.0%), small heterodimer partner (73.7%), and oxysterol 7α-hydroxylase (110%) (P < 0.05). Additionally, BA supplementation significantly decreased the ileal abundance of Lactobacillus (14.38%) but increased the abundance of Clostridium_sensu_stricto_1 (447%) and Blautia (134%) (P < 0.05). Spearman's correlation analysis indicated that hepatic BAs and ileal microbiota had strong correlations with serum total cholesterol and TG, hepatic TG, and lipogenesis-related genes.

CONCLUSIONS

Our results suggest that BA supplementation reduces hepatic lipid deposition in weaned piglets by modulating BA metabolism and gut microbiota composition.