This study investigated the protective effects of probiotic on heat stress‐induced intestinal injury and inflammatory response in broilers. A total of 180 male broilers were randomly allocated to three treatments with four replicates each from 22 to 42 days of age. The broilers were either raised under thermoneutral (TN) conditions (23 ± 1°C) or subjected to cyclic heat stress (28–35–28°C for 12 hr daily). The broilers kept at TN conditions were fed a basal diet, and those exposed to heat stress were fed basal diets supplemented with or without probiotic at a dose of 1.5 × 10⁸ cfu/kg. Compared with the TN group, heat stress decreased (p  < .05) the growth performance, reduced (p  < .05) villus height and villus height: crypt depth ratio in intestinal mucosa, increased (p  < .05) serum levels of D‐lactic acid on day 28 and endotoxin, TNF‐α and IL‐6 on day 42, and decreased (p  < .05) serum IL‐10 content on day 42. Dietary supplementation of probiotic reversed (p  < .05) all these changes except for the growth performance in heat‐stressed broilers. In conclusion, dietary inclusion of probiotic could improve intestinal morphology and barrier function, alleviate inflammatory response, but exert no ameliorative effect on growth performance of broilers under cyclic heat stress.

中文翻译：

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添加益生菌对循环热应激肉鸡生长性能、肠道形态、屏障完整性和炎症反应的影响。

本研究调查了益生菌对热应激诱导的肉鸡肠道损伤和炎症反应的保护作用。从 22 到 42 日龄，总共 180 只雄性肉鸡被随机分配到三个处理组，每个处理组重复四次。肉鸡要么在热中性 (TN) 条件（23 ± 1°C）下饲养，要么承受循环热应激（28–35–28°C，每天 12 小时）。保持在 TN 条件下的肉鸡饲喂基础日粮，而暴露于热应激的肉鸡则饲喂添加或不添加益生菌的基础日粮，益生菌剂量为 1.5 × 10 8 ^cfu  /kg。与 TN 组相比，热应激降低 ( p  < .05) 生长性能，降低 ( p < .05) 绒毛高度和绒毛高度：肠粘膜中的隐窝深度比， 第 28 天 D-乳酸血清水平和第 42 天内毒素、TNF-α 和 IL-6 血清水平升高 ( p < .05)，并降低( p  < .05) 第 42 天血清 IL-10 含量。日粮中添加益生菌可逆转 ( p  < .05) 除热应激肉鸡生长性能外的所有这些变化。综上所述，日粮中添加益生菌可以改善肠道形态和屏障功能，减轻炎症反应，但对循环热应激下肉鸡的生长性能没有改善作用。