Postbiotic GABA and Lactobacillus plantarum 1-2-3 alleviate stress-induced ovarian dysfunction and improve reproductive performance in laying hens through multi-mechanistic pathways

Stress is a well-established disruptor of reproductive function in poultry. Gamma-aminobutyric acid (GABA), a notable postbiotic derived from Lactobacillus plantarum ( L. plantarum ), has attracted increasing attention as a dietary supplement. While existing research predominantly focuses on GABA applications in broilers and other species, its effects on laying hens remain underexplored. This study investigated whether GABA and L. plantarum 1-2-3 supplementation mitigated corticosterone (CORT)-induced chronic stress in laying hens. Results demonstrated that both GABA and L. plantarum 1-2-3 effectively mitigated CORT-induced declines in laying performance and ovarian damage. They reduced ovarian oxidative stress, inflammation, and atretic follicles by enhancing antioxidant capacity and normalizing expression of inflammatory factors ( IL18 , LITAF , IL6 , IL1B) , and apoptosis-related factors ( BCL2 , BAX , CASP9 , CASP3 ). Furthermore, GABA and L. plantarum 1-2-3 markedly increased the serum reproductive hormone levels, as well as the transcription level of ovarian steroidogenic genes ( LHCGR, FSHR, StAR, CYP11A1 ), while modulated ovarian cholesterol metabolism via PPARα-mediated pathways. These findings elucidate the mechanisms by which GABA and L. plantarum 1-2-3 alleviate stress in laying hens, providing a theoretical and practical basis for their use as functional feed additives in stress-exposed flocks.