Effects of dietary supplementation of different levels of gamma-aminobutyric acid on reproductive performance, glucose intolerance and placental development of gilts.

This study aimed to investigate the effects of dietary gamma-aminobutyric acid (GABA) supplementation on reproductive performance, glucose intolerance and placental development of gilts during mid-late gestation. Based on the principle of backfat thickness consistency, 124 gilts at 65 d of gestation (G65d) were assigned to three dietary groups: CON (basic diet, n = 41), LGABA (basic diet supplemented with 0.03% GABA, n = 42) and HGABA (basic diet supplemented with 0.06% GABA, n = 41). The litter performance, glucose tolerance, placental angiogenesis and nutrients transporters were assessed. The LGABA group improved piglet vitality and placental efficiency and decreased area under the curve (AUC) of glucose tolerance test (GTT) compared to the CON group (P < 0.05). Meanwhile, the LGABA group enhanced placental vessel density, platelet endothelial cell adhesion molecule-1 (CD31) levels and gene expression of fibroblast growth factor 18 (FGF18) (P < 0.05). Furthermore, LGABA showed an uptrend in glucose transporter type 1 (GLUT1) mRNA level (P = 0.09). Taken together, this study revealed that the dietary supplementation of 0.03% GABA can improve piglet vitality, glucose intolerance and placental development of gilts.