College of Animal Science and Technology; Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province; Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing 210095, P. R. China.
School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210097, P.R. China.
Poult Sci. 2019 Jul 1;98(7):2719-2728. doi: 10.3382/ps/pez054.
This study was aimed to elucidate effects of taurine supplementation on growth performance, jejunal histology, and appetite-related genes expressions of broilers under heat stress. A total of 144 broilers on 28 d were allocated to three groups with 6 cages each group, 8 broilers per cage. The experiment period is from 28 to 42 d of age. In normal control (NC) group, chickens were held at 22°C ambient temperature (thermoneutral) and fed a basal diet. In the heat stress (HS) group, chickens were raised to constant HS at 32°C and received a basal diet. In the HS+ taurine group, chickens were fed a basal diet with 5 g/kg taurine supplementation. The results showed that HS group had lower average daily feed intake, average daily gain, higher feed/gain ratio compared with the NC group (P < 0.05), while taurine addition did not ameliorate the lowered growth performance. Cloacal temperatures and respiration rates in the HS and heat taurine group were higher (P < 0.05) than in the NC group. Heat stress treatment elevated (P < 0.05) the concentrations of ghrelin and cholecystokinin (CCK) in serum and intestine, together with peptide YY and somatostatin (SS) in the intestine after 7 or 14 d of heat exposure. In addition, HS damaged the jejunal morphology by shortening villus height and deepening crypt depth (P < 0.05), upregulated (P < 0.05) the mRNA expression of taste receptor type 1 member 1 (T1R1), taste receptor type 1 member 3 (T1R3), CCK and ghrelin in the intestine. Taurine supplementation significantly mitigated the impairment of jejunal morphology, decreased the concentrations of serum ghrelin, increased the concentrations of somatostatin and peptide YY in the duodenum, elevated the mRNA expression levels of CCK in the jejunum compared with the HS group. In conclusion, taurine exerted no positive effects on the growth performance, while mitigated the impairment of jejunal morphology, increased some anorexic hormones secretion and mRNA expression of appetite-related genes in the intestine of broilers subjected to HS.
本研究旨在阐明牛磺酸对热应激条件下肉鸡生长性能、空肠组织学和食欲相关基因表达的影响。将 144 只 28 日龄的肉鸡分为 3 组，每组 6 个笼，每个笼 8 只。试验期从 28 日龄到 42 日龄。在正常对照组（NC）中，鸡在 22°C 的环境温度（热中性）下饲养，并喂食基础日粮。在热应激组（HS）中，鸡在 32°C 的恒定热应激下饲养，并喂食基础日粮。在 HS+牛磺酸组中，鸡喂食含有 5g/kg 牛磺酸的基础日粮。结果表明，与 NC 组相比，HS 组的平均日采食量、平均日增重较低，饲料/增重比较高（P<0.05），而添加牛磺酸并不能改善生长性能的降低。HS 和热牛磺酸组的泄殖腔温度和呼吸率均高于 NC 组（P<0.05）。热应激处理后，血清和肠道中胃饥饿素和胆囊收缩素（CCK）的浓度升高（P<0.05），7 或 14 天后肠道中肽 YY 和生长抑素（SS）的浓度也升高。此外，HS 通过缩短绒毛高度和加深隐窝深度（P<0.05）破坏空肠形态，上调肠道中味觉受体 1 成员 1（T1R1）、味觉受体 1 成员 3（T1R3）、CCK 和胃饥饿素的 mRNA 表达（P<0.05）。牛磺酸补充剂显著减轻空肠形态损伤，降低血清胃饥饿素浓度，增加十二指肠中生长抑素和肽 YY 的浓度，提高空肠 CCK 的 mRNA 表达水平与 HS 组相比。综上所述，牛磺酸对生长性能没有积极影响，但减轻了热应激对肉鸡空肠形态的损伤，增加了肠道中一些厌食激素的分泌和食欲相关基因的 mRNA 表达。
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