Intracerebroventricular injection of taurine affords thermotolerance and regulates mitochondrial thermogenic gene expression in pectoralis muscle in neonatal chicks exposed to high ambient temperature

Intracerebroventricular (ICV) injection of taurine can induce hypothermia and attenuate stress behaviors in neonatal chicks under control thermoneutral temperature (CT) conditions. While, its ability to withstand heat stress (thermotolerance) has not identified yet. Thus, the objective of this study was to examine the effects of ICV taurine effects on thermoregulation, mitochondrial thermogenic gene expression, and amino acid metabolism in 5-day-old Julia male chick exposed to either high ambient temperature (HT) or CT conditions. Procedures were performed in the absence of food with water available after injections. The results showed that ICV injection of taurine reduced the magnitude of temperature rises in heat-exposed chicks (afforded thermotolerance). Central taurine increased gene expression of avian uncoupling protein mRNA in pectoral muscle under CT and HT. However, avian peroxisome proliferator-activated receptor γ coactivator-1α, avian adenine nucleotide translocase and carnitine palmitoyltransferase-I mRNA were decreased in chicks that were administered taurine under CT and HT. Diencephalic tryptophan, taurine and 3-methylhistidine were increased, while glutamic acid was decreased following taurine treatment under both CT and HT. Moreover, central taurine caused to reduce plasma triacylglycerol and uric acid concentrations. In conclusion, central taurine administration reduced temperature rises and was associated with changes in gene expression of mitochondrial thermogenic factors in heat-exposed fasted chicks. The changes in the mitochondrial thermogenic genes in muscle and amino acid concentrations in the brain suggest that skeletal muscle and central nervous system metabolism may be involved in the effects of taurine on thermoregulation in chicks under both CT and HT.