The objective of this study was to evaluate the effect of DL-methionine supplementation on the expression of genes related to immune function and intestinal integrity in the jejunum and ileum of 21- or 42-day-old broilers subjected to 38 °C for 24 h. Broilers of 1–21 and 22–42 days of age were divided into two treatments related to methionine supplementation: without DL-methionine supplementation (MD) or recommended level of DL-methionine (MS). In addition, the animals were either maintained at a comfort environment or exposed to heat stress (HS) (38 °C for 24 h, starting on day 20 or day 41 for Experiments 1 and 2, respectively). Heat stress increased body temperature and the respiratory rate of the birds in both the experimental periods evaluated (1–21 and 22–42 days of age) (body temperature: P = 0.0010 and P = 0.0005, respectively; respiratory rate: P < 0.0001). Experiment 1 (1–21-day-old broilers): in the jejunum, we observed higher heat shock protein 70 kDA (HSP70) gene expression in HS broilers fed the MD diet (P = 0.0010). Broilers from HS presented higher expression of lipopolysaccharide-induced tumor necrosis factor (TNF)-alpha factor (LITAF) (P = 0.0001), interleukin-1β (IL1B) (P = 0.0003), and claudin 1 (CLDN1) (P = 0.0391). Regarding the diet effect, the highest LITAF (P = 0.0002) and IL1B (P = 0.0067) gene expression was observed in birds fed the MD diet. In the ileum, birds from comfort and fed the MD diet presented the highest IL1B expression (P < 0.0001). Broilers from HS presented higher occludin (OCLN) expression (P = 0.0072).Experiment 2 (22–42-day-old broilers): in the jejunum, broilers from HS presented higher LITAF (P < 0.0001) and OCLN (P < 0.0001) expression gene. Broilers fed the MS diet presented higher LITAF (P = 0.0007) and IL1B (P = 0.0220) gene expression. The highest HSP70 (P < 0.0001) and CLDN1 (P = 0.0349) gene expression was observed in HS broilers fed the MD diet. In the ileum, we observed that broilers submitted to HS presented higher HSP70 (P = 0.0008), LITAF (P = 0.0044), and OCLN (P < 0.0001) gene expression. Broilers fed the MD diet presented lower CLDN1 gene expression (P = 0.0141). Our results suggest that methionine supplementation in adequate amounts may assist the body in combating the deleterious effects of stress by stimulating the expression of genes capable of maintaining intestinal epithelial cell function.

这项研究的目的是评估补充蛋氨酸对21或42日龄肉仔鸡经38°C 24 h空肠和回肠的免疫功能和肠道完整性相关基因表达的影响。将1–21日龄和22–42日龄的肉鸡分为两种与蛋氨酸补充有关的处理方法：不添加DL-蛋氨酸（MD）或推荐水平的DL-蛋氨酸（MS）。此外，将动物维持在舒适的环境中或暴露于热应激（HS）（38°C，持续24 h，分别从实验1和2的第20天或第41天开始）。在所评估的两个实验时期（1-21日龄和22-42日龄）中，热应激都会增加禽类的体温和呼吸频率（体温：P = 0.0010和P  = 0.0005；呼吸频率：P <0.0001）。实验1（1-21日龄的肉鸡）：在空肠中，我们观察到饲喂MD日粮的HS肉鸡中的热休克蛋白70 kDA（HSP70）基因表达较高（P  = 0.0010）。HS的肉鸡表现出较高的脂多糖诱导的肿瘤坏死因子（TNF）-α因子（LITAF）（P  = 0.0001），白介素1β（IL1B）（P  = 0.0003）和claudin 1（CLDN1）（P  = 0.0391 ）表达）。关于饮食效果，最高的LITAF（P = 0.0002）和 在饲喂MD日粮的禽类中观察到IL1B（P = 0.0067）基因表达。在回肠中，从舒适度和饲喂MD日粮的家禽表现出最高的IL1B表达（P <0.0001）。来自HS的肉鸡表现出更高的occludin（OCLN）表达（P  = 0.0072）。实验2（22-42日龄的肉鸡）：在空肠中，来自HS的肉鸡表现出更高的LITAF（P <0.0001）和OCLN（P <0.0001）表达基因。饲喂MS日粮的肉鸡的LITAF较高（P  = 0.0007）IL1B（P  = 0.0220）基因表达。 在饲喂MD日粮的HS肉鸡中观察到最高的HSP70（P <0.0001）和CLDN1（P = 0.0349）基因表达。在回肠中，我们观察到提交给HS的肉鸡表现出更高的HSP70（P  = 0.0008），LITAF（P  = 0.0044）和OCLN（P <0.0001）基因表达。饲喂MD日粮的肉鸡的CLDN1基因表达较低（P = 0.0141）。我们的结果表明，通过刺激能够维持肠道上皮细胞功能的基因的表达，适量补充蛋氨酸可以帮助机体抵抗压力的有害影响。