Curcumin ameliorates fatty liver hemorrhagic syndrome in broiler breeders by regulating lipid metabolism via the gut-liver axis.

Fatty liver syndrome (FLS) is closely linked to disruptions in lipid metabolism, imbalances in the gut microbiome, and alterations in bile acid composition. Curcumin (CUR), a bioactive compound derived from turmeric, has been reported to exert anti‑inflammatory and hepatoprotective effects. The present study aimed to evaluate the potential of dietary CUR to mitigate fatty liver‑related metabolic disturbances in broiler breeder hens fed a low‑protein high‑energy (LPHE) diet. A total of 600 Qingyuan partridge broiler breeder hens (42 weeks of age) were used in a randomized experimental design. Birds were allocated to five dietary regimens, including a control diet (CON), a low‑protein high‑energy diet (LPHE), and LPHE diets supplemented with CUR at 100, 200, or 400 mg/kg. Each group consisted of six replicates with 20 birds per replicate. The feeding trial was conducted over an eight‑week period. The results showed that dietary supplementation with CUR at 100 and 200 mg/kg improved productive performance by reducing feed-to-egg ratio, abnormal egg rate, fat pad mass and lipid droplet in hepatic tissue versus hens fed the LPHE diet. In addition, CUR supplementation reduced plasma and hepatic levels of TG, TCHO, and LDL, as well as ALT activity and concentrations of TGF-β and TNF-α, while elevating IL-10 and IL-22 levels (P<0.05). Bile acid profiling demonstrated that DCA levels were increased in the LPHE_CUR200 group, while GCDCA, GDCA, and TLCA were reduced relative to LPHE group. Moreover, CUR corrected LPHE-induced disruptions in lipid metabolism and bile acid regulatory genes, including FXR, BSEP, PPARα, CPT1α and CYP7A1. Metabolomics demonstrated that LPHE altered hepatic metabolism, and it was partially restored in that of LPHE_CUR100 group. Dietary supplementation with 100 to 200 mg/kg CUR enriched Lactobacillus and Peptococcus populations in cecum. In summary, dietary inclusion of CUR at 100 to 200 mg/kg improved hepatic function, lipid metabolism in broiler breeder hens subjected to the LPHE diet, which may be regulated through the gut microbiota-Bile acid axis.