South Australian Research and Development Institute, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia.
School of Animal and Veterinary Science, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia.
Poult Sci. 2019 Dec 1;98(12):6761-6771. doi: 10.3382/ps/pez393.
Changing dietary protein and amino acids may impact intestinal barrier function. Experiments were conducted in broiler chickens to evaluate supplementation of L-glutamine, glycine, and L-arginine in a reduced protein (RP) diet. Experiment 1 examined the growth performance of broilers fed 5 dietary treatments: 1) a standard diet; 2) an RP diet (193.9 g/kg CP in grower and 176.9 g/kg CP in finisher); 3) RP diet supplemented with 10 g/kg L-Gln; 4) RP diet supplemented with 10 g/kg Gly; 5) RP diet supplemented with 5 g/kg L-Arg. Each experimental diet was replicated 6 times with 10 birds per replicate. In a subset of 96 birds, experiment 2 tested the 4 RP diets with and without dexamethasone (DEX) to induce leaky gut. Each diet was replicated 24 times. Fluorescein isothiocyanate dextran (FITC-d) was used to test intestinal permeability (IP). Gene expression of selected tight junction proteins in ileal and jejunal tissues was assayed by quantitative PCR. From day 7 to 35, the RP diet increased feed intake (FI) (P < 0.05) and body weight gain (BWG) compared with the standard diet while Gln reduced FI and BWG (P < 0.05) compared with RP. Gly had no effect on BWG or FCR. Supplementation of Arg improved FCR from day 21 to 35 and day 7 to 35. In experiment 2, Arg tended to lower FITC-d (P = 0.086). DEX increased passage of FITC-d into the serum (P < 0.001). The villi surface area was increased in birds fed higher Arg (P < 0.05). DEX and diet interacted (P < 0.01) for jejunal claudin-3 mRNA level where DEX upregulated claudin-3 for all diets except the Arg diet. In summary, with a moderate reduction of protein, satisfactory performance can be obtained. Although Gln and Gly had no demonstrable positive effect on IP and performance of broilers, increasing the dietary Arg by approximately 140% improved FCR and showed indications of improved intestinal barrier function of birds fed an RP diet under a stress model.
改变饮食中的蛋白质和氨基酸可能会影响肠道屏障功能。本实验在肉鸡中进行，以评估在低蛋白（RP）日粮中添加 L-谷氨酰胺、甘氨酸和 L-精氨酸对肠道屏障功能的影响。实验 1 考察了饲喂 5 种日粮的肉鸡的生长性能：1）标准日粮；2）RP 日粮（生长期 CP 为 193.9g/kg，育肥期 CP 为 176.9g/kg）；3）RP 日粮添加 10g/kg L-谷氨酰胺；4）RP 日粮添加 10g/kg 甘氨酸；5）RP 日粮添加 5g/kg L-精氨酸。每种实验日粮设 6 个重复，每个重复 10 只鸡。在 96 只鸡的亚组中，实验 2 测试了 4 种 RP 日粮添加和不添加地塞米松（DEX）以诱导肠漏的情况。每种日粮设 24 个重复。使用荧光素异硫氰酸酯葡聚糖（FITC-d）检测肠道通透性（IP）。通过定量 PCR 检测回肠和空肠组织中选定的紧密连接蛋白的基因表达。从第 7 天到第 35 天，与标准日粮相比，RP 日粮增加了采食量（FI）（P < 0.05）和体重增加（BWG），而与 RP 日粮相比，谷氨酰胺降低了 FI 和 BWG（P < 0.05）。甘氨酸对 BWG 或饲料转化率（FCR）没有影响。添加精氨酸可从第 21 天到第 35 天和第 7 天到第 35 天改善 FCR。在实验 2 中，精氨酸有降低 FITC-d 的趋势（P = 0.086）。DEX 增加了 FITC-d 进入血清的量（P < 0.001）。饲喂高精氨酸的鸡的绒毛表面积增加（P < 0.05）。DEX 和日粮相互作用（P < 0.01）影响空肠闭合蛋白-3mRNA 水平，DEX 上调了除精氨酸日粮外的所有日粮的闭合蛋白-3。总之，在适度降低蛋白质的情况下，肉鸡可以获得满意的生产性能。虽然谷氨酰胺和甘氨酸对 IP 和肉鸡性能没有明显的积极影响，但在应激模型下，日粮中精氨酸的添加量增加约 140%可改善 FCR，并显示出改善肠道屏障功能的迹象。
