Dietary porcine bile acids alleviate lipid deposition and remodel ileal bile acid and microbiota profiles in laying hens fed a high-fat soybean meal-based diet.

This study was conducted to evaluate whether dietary porcine bile acids (PBA) alleviate lipid metabolic burden in laying hens fed a high-fat soybean meal-based diet. A total of 270 Hy-Line Brown laying hens at 60 wk of age were assigned to 3 dietary treatments for 12 wk: a corn-soybean meal basal diet (CON), a diet containing 20% high-fat soybean meal (HFSBM), and HFSBM supplemented with 60 mg/kg PBA (HFSBM+PBA). HFSBM reduced egg production during wk 9 to 12 and throughout the 12-wk feeding period (P = 0.001), whereas HFSBM+PBA maintained egg production at a level comparable with CON. Most conventional egg-quality traits, including egg shape index, albumen height, Haugh unit, yolk proportion, and eggshell strength, were not affected (P > 0.05). HFSBM increased serum triglyceride (TG), abdominal fat rate, hepatic TG, yolk total cholesterol (TC), and yolk TG, whereas PBA supplementation reduced serum TG (P = 0.005), prevented abdominal fat accumulation (P = 0.043), lowered hepatic TG (P < 0.001), restored yolk TC to a level comparable with CON (P = 0.041), and produced an intermediate response in yolk TG. Histological staining showed more apparent hepatocellular vacuolation and neutral lipid staining in HFSBM-fed hens, both of which appeared less prominent after PBA supplementation. Compared with HFSBM, HFSBM+PBA downregulated hepatic acetyl-CoA carboxylase, fatty acid synthase, and lipoprotein lipase expression (P < 0.05). Ileal bile acid profiling showed that PBA supplementation increased hyocholic acid, glycohyocholic acid, hyodeoxycholic acid, taurohyodeoxycholic acid, murideoxycholic acid, and taurodeoxycholic acid (P < 0.05), while tauroursodeoxycholic acid was reduced by HFSBM and partially restored by PBA. Ileal microbiota analysis showed increased Simpson diversity (P < 0.05), distinct community separation, enrichment of Ligilactobacillus, and reduced Enterococcus abundance in HFSBM+PBA hens. In conclusion, 60 mg/kg PBA prevented the decline in egg production observed with HFSBM and attenuated lipid deposition in laying hens, accompanied by downregulation of hepatic lipid metabolism-related genes and remodeling of ileal bile acid and microbial profiles.