Postbiotic GABA and Lactobacillus plantarum 1-2-3 Alleviate Corticosterone-induced Abdominal Fat Deposition in Laying Hens by Suppressing Adipogenesis and Enhancing Lipolysis

Intensive poultry farming has significantly increased the incidence of lipid metabolic disorders, severely compromising the economic benefits of poultry industry. Currently, gamma-aminobutyric acid (GABA) is primarily used to mitigate adverse effects of heat stress in poultry, while the effects and mechanisms of GABA on lipid metabolism disorders remain underexplored. Lactobacillus plantarum ( L. plantarum ) serves as a significant source of GABA and is widely used in the livestock industry. This study therefore examines the effects of postbiotic GABA and the GABA-producing probiotic L. plantarum 1-2-3 on abdominal adipose tissue of laying hens following corticosterone-induced stress. To this end, hens subjected to corticosterone subcutaneous injections (4 mg/kg of body weight) were respectively received GABA (100 mg/kg BW) or L. plantarum 1-2-3 (1 × 10⁹ CFU/day). Results demonstrated that both GABA and L. plantarum 1-2-3 alleviated corticosterone-induced lipid metabolism disorders and reduced adipocyte size in abdominal fat. Additionally, expression analyses of genes and proteins related to lipid metabolism (PPARγ, C/EBPα, CD36, LPL, ATGL, and HSL) further showed that GABA and L. plantarum 1-2-3 inhibited excessive deposition of abdominal lipids in laying hens by suppressing adipogenesis and lipogenesis, while promoting lipolysis. Moreover, GABA and L. plantarum 1-2-3 both mitigated lipid deposition-induced inflammation and oxidative damage by normalizing macrophage infiltration and improving antioxidative enzyme activities (GSH-Px, T-SOD, CAT). These findings demonstrate the efficacy of GABA and L. plantarum 1-2-3 in alleviating lipid metabolism disorders in the abdominal adipose tissue of laying hens, suggesting their promise as nutritional supplements for counteracting stress-induced metabolic dysfunction.