To explore the effect of glutamine (Gln) on the growth performance, digestive enzyme activity, absorption function and mRNA expression of intestinal transporters in heat-stressed chickens, 540 21-day-old Arbor Acres broilers were randomly assigned to a control group (no stress, NS), Gln group (Chickens were administered 0.5% and 1.0% Gln, respectively), heat stress group (HT), and Gln + HT group (Chickens were administered 0.5% and 1.0% Gln, respectively). The chickens in the HT and Gln + HT groups were reared under HT (36 ± 1 °C for 10 h/d and 22 ± 1 °C for 14 h/d), for 21 days. In contrast to the NS group, heat stress caused a reduction in the body weight gain (BWG); feed intake (FI); activity of trypsin, lipase, alkaline phosphatases, Ca²⁺ and Mg²⁺ adenosine triphosphatases, and Na⁺-K⁺-ATPase; and content of glutathione and d-xylose (P < 0.05) in the other groups.

In addition, compared to the F:G and expression levels in the NS group, the heat stress increased the feed intake:body weight gain (F:G) and mRNA expression levels of SGLT1, CaBP-D28k, and L-GSBP (P < 0.05). Furthermore, HT-challenged birds were pretreated with Gln, the BWG; FI; activity of trypsin, lipase, alkaline phosphatase, Ca²⁺ and Mg²⁺ adenosine triphosphatases, and Na⁺-K⁺-ATPase; and content of glutathione and d-xylose (P < 0.05) were dramatically increased, but it decreased the F:G and mRNA expression levels of SGLT1, CaBP-D28k, and L-GSBP (P < 0.05) in the HT group. In summary, Gln can effectively improve growth performance and may promote digestion and absorption in the gastrointestinal tract by mediating the mRNA expression level of nutrient transporters and Gln metabolism in heat-stressed broilers.

为了研究谷氨酰胺（Gln）对热应激鸡的生长性能，消化酶活性，吸收功能和肠道转运蛋白mRNA表达的影响，将540只21日龄的Arbor Acres肉鸡随机分为对照组（无应激，NS），Gln组（分别给鸡施用0.5％和1.0％的Gln），热应激组（HT）和Gln + HT组（给鸡施用0.5％和1.0％的Gln）。HT和Gln + HT组的鸡在HT（36±1°C持续10 h / d和22±1°C持续14 h / d）下饲养21天。与NS组相反，热应激导致体重增加（BWG）降低；饲料摄入量（FI）；胰蛋白酶，脂肪酶，碱性磷酸酶，Ca ²⁺和Mg ²⁺腺苷三磷酸酶和Na的活性⁺ -K ⁺ -ATPase;  其他组中谷胱甘肽和d-木糖的含量（P <0.05）。

此外，与NS组的F：G和表达水平相比，热应激增加了SGLT1，CaBP-D28k和L-GSBP的采食量：体重增加（F：G）和mRNA表达水平（P  <0.05）。此外，用Gln（BWG）预处理HT攻击的家禽；FI; 胰蛋白酶，脂肪酶，碱性磷酸酶，Ca ²⁺和Mg ²⁺腺苷三磷酸酶以及Na ⁺ -K ⁺ -ATPase的活性；谷胱甘肽和d-木糖含量 显着增加（P <0.05），但降低了SGLT1，CaBP-D28k和L-GSBP的F：G和mRNA表达水平（P <0.05）。综上所述，Gln可以通过介导热应激肉鸡的营养转运蛋白的mRNA表达水平和Gln代谢来有效提高生长性能，并可以促进胃肠道的消化吸收。