低蛋白日粮添加蛋氨酸、赖氨酸、亮氨酸和异亮氨酸对大鼠生长性能和血液生化指标的影响

Effect of adding methionine,lysine,leucine and isoleucine to low-protein diets on growth performance and blood biochemical indices of rats

试验旨在研究低蛋白日粮补饲蛋氨酸(Met)、赖氨酸(Lys)、亮氨酸(Leu)和异亮氨酸(Ile)对大鼠生长性能、消化性能、血液生化指标及调控肌肉合成信号通路蛋白质表达的影响。选取60只28日龄健康SD大鼠,初始体重为(90.0±1.6) g,随机分为5组,每组12个重复。高蛋白日粮为正对照组(HP组),低蛋白日粮为负对照组(LP组),低蛋白日粮+Met+Lys (LP+ML组),低蛋白日粮+Ile和Leu (LP+IL组),低蛋白日粮+Met、Lys、Ile和Leu (LP+MIIL组)。试验期14 d。结果显示,与HP组相比,其他组大鼠末重、平均日增重均显著降低(P<0.05),肝脏、后肢、肾脏、胃、十二指肠、脾脏、心脏和胴体重等屠宰指标均极显著降低(P<0.01),白蛋白、尿素和甘油三酯含量均显著降低(P<0.05);LP+MIIL组大鼠的IGF-1含量显著高于HP组和LP组(P<0.05);LP+MIIL组和LP+IL组大鼠的生长激素、胰岛素含量显著高于HP组和LP组(P<0.05);HP组和LP组大长鼠的胰高血糖素含量显著高于其他3组(P<0.05);HP组大鼠的色氨酸、苯丙氨酸、亮氨酸、异亮氨酸、缬氨酸、蛋氨酸、酪氨酸和苏氨酸的含量均极显著高于其他组(P<0.01),谷氨酸、天冬酰胺的含量显著高于其他组(P<0.05);LP+ML组、LP+IL组和LP+MIIL组大鼠肌肉组织西罗莫司靶蛋白磷酸化水平显著提高(P<0.05)。研究表明,低蛋白日粮添加赖氨酸、蛋氨酸、亮氨酸和异亮氨酸,提高了大鼠肌肉组织西罗莫司靶蛋白及其下游蛋白质的磷酸化水平,促进肌肉组织蛋白质合成;可维持血糖含量稳定,有助于提高大鼠免疫力,降低不良应激。

The experiment was to study the effect of supplementary methionine(Met), lysine(Lys), leucine(Leu) and isoleucine(Ile) in low-protein diets on growth performance, digestion performance, blood biochemical indicators and regulation of protein expression in muscle synthesis signaling pathway of rat. 60 healthy 28-day-old SD rats with an initial weight of(90.0±1.6) g were selected and randomly divided into five groups, with 12 rats in each replicates. The high-protein diet was the positive control group(HP group), the low-protein diet was the negative control group(LP group), low protein diet+Met + Lys was LP + ML group, low protein diet+Ile and Leu was LP + IL group, and low protein diet+Met, Lys, Ile and Leu was LP + MIIL group. The experiment lasted for 21 d. The results showed that compared with the HP group, the final weight and average daily gain of other groups were significantly reduced(P<0.05).The slaughter indexes of liver, hindlimbs, kidneys, stomach, duodenum, spleen, heart and carcass in other groups were extremely reduced(P<0.01). The contents of albumin, urea and triglycerides in other groups were significantly reduced(P<0.05). IGF-1 content in LP + MIIL group was significantly higher than that in HP group and LP group(P<0.05). The growth hormone and insulin content of rats in LP + MIIL group and LP + IL group were significantly higher than those in HP group and LP group(P<0.05). The GLN content of HP group and LP group was significantly higher than other groups(P<0.05). The content of tryptophan, phenylalanine,leucine, isoleucine, valine, methionine, tyrosine and threonine in the HP group were extremely higher than those in other groups(P<0.01). The content of acid and asparagine was significantly higher than other groups (P<0.05). LP + ML group, LP + IL group and LP + MIIL group significantly increased the phosphorylation level of rapamycin target protein in muscle tissue(P<0.05). The experiment indicates that adding lysine, methionine, leucine and isoleucine to low-protein diets can increase the phosphorylation level of rapamycin target protein and its downstream proteins in muscle tissue, promote protein synthesis in muscle tissue, maintain stable blood sugar levels, improve rat immunity, and reduce adverse stress.