Effects of dietary supplementation with Aspergillus Awamorion growth performance and antioxidative status of broiler chickens exposed to high ambient temperature

Abstract

This study was conducted to evaluate the effects of dietary supplementation with Aspergillus awamorion the growth performance and antioxidative status in male broiler chickens exposed to high ambient temperatures. Twentyfour 15-d-old male broiler chickens were randomly divided into 2 dietary groups fed a corn-soybean meal-based diet supplemented without or with 0.05% of Asp. awamori. Six birds of each dietary group were kept under a thermoneutral condition (22°C), and 6 birds were exposed to heat stress (35°C, 9 h/d) for 15 d. Dietary Asp. awamori decreased feed intake and improved the feed conversion ratio in chickens kept at 22°C. Body weight gain and feed intake were decreased in chickens exposed to heat stress. There was no beneficial effect of dietaryAsp. awamorion growth performance under the heat stress condition. However, the malondialdehyde content in skeletal muscle, as an index of lipid peroxidation, was decreased by dietary Asp. awamoriin chickens kept at 22°C. Although the malondialdehyde content increased under the heat stress condition, dietary Asp. awamorialleviated the increased malondialdehyde. In addition, theα-tocopherol content in skeletal muscle was negatively affected by the exposure to heat stress, and dietary Asp. awamorirecovered the reduction in the α-tocopherol content. Moreover, mRNA expression of glutathione peroxidase in liver was increased by dietary Asp. awamoriunder both of the thermal conditions. In conclusion, this study shows that dietary Asp. awamori improves the diminished antioxidative status under the heat stress condition partially because of its effect on the expression of hepatic antioxidant enzymes in broilers. © 2014, Japan Poultry Science Association.