Guanidinoacetic acid supplementation improves intestinal morphology, mucosal barrier function of broilers subjected to chronic heat stress.

With the global warming getting worse, heat stress (HS) has been a serious problem faced by poultry industry. As one of the main target organs, the intestine is easily affected by HS. Broilers are particularly sensitive to hot temperatures, and HS occurs when temperatures rise above the optimum (16­26 °C). Moreover, ambient humidity below 40% and above 80% also affects broilers adversely. HS can impair intestinal morphology and function of the intestinal barrier. The intestinal mucosal barrier not only plays key roles in nutrient digestion and absorption but also serves as the innate defense barrier fending off noxious substances within the intestinal luminal environment. Therefore, protecting intestinal mucosal barrier from HS is important to animal health. Nutrient regulation is an economical and effective method to alleviate HS of intensively-farmed broiler chickens. The results of current study demonstrated that chronic HS impaired the growth performance and intestinal mucosal barrier function of broilers, while dietary supplementation with 0.6 g/kg guanidinoacetic acid improved intestinal histomorphology and alleviated intestinal barrier dysfunction of broilers subjected to chronic HS, which is beneficial for improving health of broilers.