Effects of Heat Stress on the Development of GABAergic Neurons in the HPG Axis of Wenchang Chicks

Abstract

This study conducted an in-depth investigation on the development of GABAergic neurons and their receptors in HPG axis-related target organs of Wenchang chicks under heat stress. One-day-old healthy Wenchang chicks were randomly divided into control (CK) and heat stress (HS) groups. Chicks in the HS group were placed in a 40±0.5°C climatic chamber for HS treatment from 13:00 to 15:00 daily. By immunohistochemistry and Western blotting, GABA and GABA A receptor (GABA A R) expression in the hypothalamus of the HS group was significantly higher (p<0.05), but GABA B receptor (GABA B R) expression was significantly lower than that of the CK group (p<0.05). Expression of GABA and its two receptors in the pituitary tissues of the HS group was significantly lower than in the CK group (p<0.05). Expression of GABA and GABA B R in ovaries in the HS group was significantly higher, but expression of GABA A R in the testes of the HS group was lower than that of the CK group (p<0.05). In the male chicks, expression of GABA and its two receptors in the hypothalamus, pituitary, and testicular tissues of the HS group was significantly higher than that of the CK group (p<0.05). Western blotting showed that the GABA A R and GABA B R expression of the HS group was significantly higher than that of the CK group at 3 and 5 weeks of age. Thus, HS caused GABAergic nervous system disorder in the HPG axis of Wenchang chicks and seriously hindered the normal development of GABAergic neurons in chicks, leading to the disorder of the expression of GABA and its receptors in tissues.

Effects of Heat Stress on Expression of Heat Shock Proteins in the Small Intestine of Wenchang Chicks

“…Previous studies have shown that a high-temperature environment causes heat stress and hinders the normal development of chicks, manifesting in damage to the thymus , bursa of fabricius , and small intestine (Chen, et al, 2015). Heat stress also disrupts the expression of the mitogen-activated protein kinases (MAPKs) signaling pathway (Li, et al, 2020) and the GABAergic system (Liang, et al, 2019) on the hypothalamic-pituitarygonadal (HPG) axis in chicks. The intestine plays important roles in digestion, nutrient absorption, and substance transport in the body and is particularly sensitive to heat stress.…”