Lactobacillus plantarum 1-2-3 Ameliorates the Corticosterone-Induced Fatty Liver Hemorrhagic Syndrome in Laying Hens by Biosynthesizing Gamma-Aminobutyric Acid.

Fatty liver hemorrhagic syndrome (FLHS) has become a common and serious disease in intensive laying hen farming, seriously endangering the productivity and health of laying hens. Although probiotics have been recognized as an emerging candidate therapeutic strategy for liver disease, their effective substances and mechanisms for alleviating FLHS remain to be elucidated. In this study, corticosterone (Cort) was applied to induce FLHS in laying hens, and Lactobacillus plantarum (L. plantarum 1-2-3) was used for the intervention. The results showed that L. plantarum 1-2-3 treatment significantly ameliorated Cort-induced hepatic steatosis and liver damage in laying hens, as evidenced by decreased levels of triglyceride (TG), total cholesterol (TC), aspartate aminotransferase, and alanine aminotransferase. Importantly, we found that L. plantarum 1-2-3 could biosynthesize gamma-aminobutyric acid (GABA) by expressing glutamic acid decarboxylase. Surprisingly, feeding GABA to laying hens replicated the effect of L. plantarum 1-2-3 in alleviating Cort-induced FLHS. GABA significantly down-regulated the mRNA expression of Acc, Fasn, Cd36, and Gpam while upregulating the levels of Ppara and Cpt1a. An in vitro verification study showed that GABA decreased TG and TC content in Leghorn male hepatoma cells. Moreover, GABA significantly enhanced antioxidant enzyme activity, inhibited oxidative stress in hepatocytes, regulated the AMPK/NLRP3 signaling pathway, and reduced the protein expression of NF-κB, TNFα, and IL-1β. In conclusion, our study demonstrated that L. plantarum 1-2-3 could effectively alleviate FLHS in laying hens, while GABA was an important postbiotic for L. plantarum 1-2-3 to exert lipid-lowering and anti-inflammatory effects.