ABSTRACT The use of natural antioxidants, in particular polyphenols such as dihydroquercetin (DHQ), in animal nutrition has recently increased in popularity. This may partly be due to the risk of increased incidences of heat stress associated with raising livestock in warmer ambient temperatures, facilitated by global warming, reducing antioxidant capacity. The current research demonstrates the effect of dietary DHQ, vitaminEand standard or high ambient temperatures on growth performance, energy and nutrient metabolism, gastrointestinal tract (GIT) development, jejunal villus morphometry and antioxidant status in broiler chickens. Each of the four experimental diets was fed to 16 pens of five birds, which were allocated to four rooms (four pens in each room). The temperature in two rooms was maintained at aconstant 35°C (high temperature; HT), and the temperature in the other two rooms was gradually reduced from 27°C at 7 dof age to 22°C at 20 dof age (standard temperature; ST). Rearing birds at HT reduced feed intake, weight gain, weight of small intestine, total GIT, liver, spleen, heart, villus height, villus surface area and lowered blood glutationperoxidase (GSH-Px). Dietary DHQ increased blood GSH-Px and total antioxidant status, increased heart weight and reduced caecal size. When fed separately, DHQ and vitamin E improved hepatic vitamin E concentration. Feeding vitamin Eincreased spleen and liver weights. When fed together, DHQ and vitamin Ereduced villus height, villus height to crypt depth ratio and villus surface area. Temperature and antioxidants did not affect energy and nutrient metabolism. There were no effects of dietary antioxidants on growth performance of broiler chickens and there were no mortalities. At present, it is unclear if feeding antioxidants (in particular DHQ) at different levels, using different dietary formulations, and rearing birds under arange of environmental conditions may be effective at enhancing production performance and bird health in hot ambient climates.

中文翻译：

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给在标准和高环境温度下饲养的肉鸡饲喂二氢槲皮素和维生素 E

摘要 最近，在动物营养中使用天然抗氧化剂，特别是多酚，如二氢槲皮素 (DHQ)，越来越受欢迎。这可能部分是由于与在温暖的环境温度下饲养牲畜相关的热应激发生率增加的风险，全球变暖促进了抗氧化能力的降低。目前的研究证明了日粮 DHQ、维生素 E 和标准或高环境温度对肉鸡生长性能、能量和营养代谢、胃肠道 (GIT) 发育、空肠绒毛形态测定和抗氧化状态的影响。四种实验日粮中的每一种都喂给 16 只鸡的 5 只鸡，这些鸡被分配到四个房间（每个房间四只鸡）。两个房间的温度保持在恒定的 35°C（高温；HT），其他两个房间的温度从7度时的27℃逐渐降低到20度时的22度（标准温度；ST）。在 HT 饲养鸟类减少了采食量、体重增加、小肠重量、总 GIT、肝脏、脾脏、心脏、绒毛高度、绒毛表面积和降低的血液谷氨酸过氧化物酶 (GSH-Px)。膳食 DHQ 增加了血液 GSH-Px 和总抗氧化状态，增加了心脏重量并减少了盲肠大小。单独喂食时，DHQ 和维生素 E 可提高肝脏维生素 E 浓度。喂食维生素E增加脾脏和肝脏的重量。当一起喂食时，DHQ 和维生素 E 降低了绒毛高度、绒毛高度与隐窝深度之比和绒毛表面积。温度和抗氧化剂不影响能量和营养代谢。日粮抗氧化剂对肉鸡的生长性能没有影响，也没有死亡。目前，尚不清楚饲喂不同水平的抗氧化剂（特别是 DHQ）、使用不同的日粮配方以及在一系列环境条件下饲养鸟类是否能有效提高炎热环境气候下的生产性能和鸟类健康。