Maternal Dietary Supplementation with γ-Aminobutyric Acid Alleviated Oxidative Stress in Gestating Sows and Their Offspring by Regulating GABRP

SIMPLE SUMMARY: Sows usually suffer oxidative stress during gestation, and this limits the growth of fetuses via placenta. Gamma-aminobutyric acid (GABA) is a functional nonessential amino acid engaged in regulating the physiological status of animals. However, the effects of GABA on the oxidative homeostasis of sows and their offspring remain unclear. This study aims to investigate the effects of GABA on the oxidative stress of gestating sows, newborn piglets, as well as the H(2)O(2)-treated porcine trophectoderm cell line-2 (pTr-2 cells) and to subsequently provide guidance on the application of GABA in sows’ nutrition during late gestation. We found that GABA alleviated placental oxidative stress in gestating sows by increasing antioxidant-associated enzyme activity and by upregulating the gene expressions of gamma-aminobutyric acid receptor (GABRP) and nuclear factor-erythroid 2-related factor-2 (Nrf2) in pTr-2 cells, as well as enhanced the antioxidant capacity of sows and fetal piglets. This study provides the possibility for future application of GABA in maternal–fetal nutrition. ABSTRACT: Sows usually suffer oxidative stress during gestation, and this limits the growth of fetuses via placenta. Gamma-aminobutyric acid (GABA) is a functional nonessential amino acid engaged in regulating the physiological status of animals. However, the effects of GABA on the oxidative homeostasis of sows and their offspring remain unclear. Eighteen late gestating sows (85 d) were divided into the CON and GABA groups and fed the basal diet and the GABA diet (200 mg/kg GABA), respectively, until farrowing. At parturition, the sows’ litter characteristics, the plasma antioxidant parameters of sows, and their offspring were evaluated. The results showed that GABA supplementation had no marked effect on the reproductive performance of sows (p > 0.10) but had a trend of reducing the amount of intrauterine growth restriction (IUGR) in piglets (0.05 < p < 0.10). At the same time, the addition of GABA elevated the plasma superoxide dismutase (SOD) level of sows and enhanced the glutathione peroxidase (GSH-Px) activity of newborn piglets (p < 0.05). Based on the H(2)O(2)-induced oxidative stress in pTr-2 cells, GABA elevated intracellular GSH-Px, SOD, catalase (CAT), and total antioxidant capacity (T-AOC, p < 0.01) and upregulated the gene expressions of CAT, gamma-aminobutyric acid receptor (GABRP), and nuclear factor-erythroid 2-related factor-2 (Nrf2) in H(2)O(2)-treated pTr-2 cells (p < 0.05). Taken together, GABA improved the antioxidant capacity of sows and alleviated the placental oxidative stress by upregulating the GABRP and Nrf2 genes, which have the potential to promote oxidative homeostasis in newborn piglets.