South Australian Research and Development Institute, Roseworthy Campus, Roseworthy, SA, Australia.
School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA, Australia.
J Anim Physiol Anim Nutr (Berl). 2021 Jan;105(1):90-98. doi: 10.1111/jpn.13416. Epub 2020 Jul 12.
Reducing crude protein and supplementation with synthetic amino acids in poultry nutrition is a recent trend to avoid wastage of protein and ammonia in production systems. Stress has been shown to impair intestinal barrier and increase inflammatory response. This study was performed on intestinal tissues of broiler chickens to understand the mechanism of stress induced by a synthetic glucocorticoid, dexamethasone (DEX) and the effect of supplementation of arginine, glutamine and glycine in reduced protein diets. Intestinal tissue samples from a previous study were utilized. Male Ross 308 chickens received a basal diet for the first seven days and then fed with crude protein that was reduced to 194 g/kg in grower experimental diets supplemented with glutamine, glycine and additional arginine at 10, 10 and 5 g/kg respectively. Half of the 96 individual birds were injected with DEX (0.5 mg/kg body weight) or saline on days 14, 16, 18 and 20 of age. mRNA expression for jejunum and ileum for amino acid transporters (y+LAT-1, B AT, EAAT-3 and CAT-1), mechanistic genes (SGLT-1, mTOR, IAP and FABP-2) and pro-inflammatory genes (MUC-2, NF-κB, iNOS, IL-8 and IL-1β) were analysed using real-time PCR. The results showed that DEX decreased y+ LAT1 in jejunum, B AT and EAAT-3 in ileum. Arginine increased CAT-1 in the jejunum and ileum under DEX treatment. Through an interaction, DEX reduced IAP in jejunum of glycine and arginine supplemented group and reduced mTOR in jejunum independently. DEX reduced MUC-2 and iNOS in jejunum and increased iNOS and IL8 in the ileum. Amino acid supplementation did not appear to ameliorate these effects; however, there were some positive effects of glycine on NF-κB and arginine through increased CAT-1. Mechanistic understanding of amino acid supplementation in broiler diets warrants further research particularly when dietary protein is reduced below the level tested in the present study.
在禽类营养中降低粗蛋白并补充合成氨基酸是避免生产系统中蛋白质和氨浪费的一种新趋势。应激已被证明会损害肠道屏障并增加炎症反应。本研究在肉鸡的肠道组织上进行，以了解合成糖皮质激素地塞米松（DEX）诱导应激的机制，以及在低蛋白日粮中补充精氨酸、谷氨酰胺和甘氨酸的影响。本研究使用了先前研究中的肠道组织样本。雄性罗斯 308 肉鸡在最初的七天内接受基础日粮，然后在生长实验日粮中摄入粗蛋白减少至 194 g/kg，同时补充谷氨酰胺、甘氨酸和额外的精氨酸，分别为 10、10 和 5 g/kg。96 只个体鸡中的一半在 14、16、18 和 20 日龄时用 DEX（0.5mg/kg 体重）或生理盐水注射。使用实时 PCR 分析空肠和回肠中氨基酸转运体（y+LAT-1、B AT、EAAT-3 和 CAT-1）、机械基因（SGLT-1、mTOR、IAP 和 FABP-2）和促炎基因（MUC-2、NF-κB、iNOS、IL-8 和 IL-1β）的 mRNA 表达。结果表明，DEX 降低了空肠中的 y+LAT1、回肠中的 B AT 和 EAAT-3。精氨酸在 DEX 处理下增加了空肠和回肠中的 CAT-1。通过相互作用，DEX 减少了添加甘氨酸和精氨酸的回肠中 IAP，并独立减少了空肠中的 mTOR。DEX 降低了空肠中的 MUC-2 和 iNOS，并增加了回肠中的 iNOS 和 IL8。氨基酸补充似乎没有改善这些影响；然而，甘氨酸对 NF-κB 和精氨酸通过增加 CAT-1 有一些积极影响。在肉鸡日粮中补充氨基酸的机制需要进一步研究，特别是当日粮蛋白水平低于本研究测试水平时。
