This study evaluated protective effects of synbiotic on meat quality and oxidative status of breast muscle in heat-stressed broilers. Twenty 2-day-old broilers were allocated in a 2×2 factorial design, and the main factors consisted of synbiotic level (0 (basal diet) or 1.5 g/kg synbiotic) and temperature (thermoneutral or high temperature), resulting in 4 treatments. From 22 to 42 days, chickens were raised at thermoneutral temperature (22 °C) or subjected to cyclic high temperature (heat stress, HS) by keeping them at 32–33 °C for 8 h and 22 °C for rest 16 h daily. Cyclic HS decreased relative weight, redness (45 min), and pH values (45 min and 24 h) but increased contents of moisture and ether extract, lightness (45 min and 24 h), drip loss (24 h and 48 h), and cooking loss in breast muscle of broilers compared with those under thermoneutral temperature. It also increased malondialdehyde content and mRNA abundances of heat shock protein 70 (HSP70) and HSP90 but decreased glutathione (GSH) concentration and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as mRNA abundances of nuclear factor (erythroid 2)-like 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), GSH-Px, and copper and zinc superoxide dismutase in breast muscle in broilers. Dietary synbiotic supplementation was effective in increasing weight and reducing lightness (45 min), drip loss (24 h and 48 h) and cooking loss of breast muscle in heat-stressed broilers compared with those fed the basal diet. It also reduced malondialdehyde content and HSP70 mRNA abundance and increased GSH-Px activity, GSH content, and mRNA abundances of Nrf2, NQO1 and GSH-Px in breast muscle of heat-stressed broilers. These results suggested that synbiotic supplementation at a level of 1.5 g/kg could ameliorate compromised meat quality and oxidative status in broilers under cyclic HS.

这项研究评估了合生素对热应激肉鸡肉品质和胸肌氧化状态的保护作用。以2×2因子设计分配了20只2日龄的肉鸡，主要因素包括合生素水平（0（基本饮食）或1.5 g / kg合生菌）和温度（高温或高温），导致4治疗。在22到42天之间，将鸡饲养在热中性温度（22°C）或通过将它们保持在32–33°C 8小时，并在22°C每天休息16小时而经受周期性高温（热应激，HS） 。循环HS降低了相对重量，发红（45分钟）和pH值（45分钟和24小时），但增加了水分和乙醚提取物的含量，亮度（45分钟和24小时），滴水损失（24小时和48小时），与热中性温度下相比，肉鸡胸肌的蒸煮损失。它还增加了热激蛋白70（丙二醛含量和mRNA丰度）（HSP70）和HSP90但降低了谷胱甘肽（GSH）的浓度以及超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-Px）的活性，并降低了核因子（类胡萝卜素2）样2（Nrf2），NAD（P）的mRNA含量肉鸡胸肌中的）H醌脱氢酶1（NQO1），GSH-Px以及铜和锌超氧化物歧化酶 与饲喂基础饲料的肉鸡相比，膳食合生素的补充可有效增加热应激肉鸡的体重并减轻其体重（45分钟），减少滴水（24h和48h）以及蒸煮胸肉的损失。它还降低了丙二醛含量和HSP70 mRNA的丰度，并增加了Nrf2的GSH-Px活性，GSH含量和mRNA丰度，热应激肉鸡胸肌中的NQO1和GSH-Px。这些结果表明，在周期HS下，1.5 g / kg的合生素补充水平可以改善肉鸡的肉质和氧化状态。