饲粮粗蛋白质水平对肉仔鸡肠道PepT1和b^(o,+) AT mRNA表达的影响

Effect of crude protein level of diets on mRNA expression of PepT1 and b^(o,+) AT at intestinal of broilers

【目的】研究饲粮粗蛋白质水平对肉仔鸡肠道PepT1和b^(o,+)AT mRNA表达的影响.【方法】选用240只21d‘科宝’肉公鸡,随机分为3组,分别饲喂粗蛋白质水平为16%(16%CP组),18%(18%CP组)和20%(20%CP组)的3种饲粮,每组设8个重复,每个重复10只鸡,42d测定肠道PepT1和b^(o,+)AT mRNA含量.【结果】16%CP组平均日增质量、氮利用率和代谢能值均显著低于其他2组(P<0.05),而料肉比显著高于其他2组(P<0.05).PepT1mRNA表达以空肠最高,十二指肠次之,回肠最低,且空肠显著高于十二指肠和回肠(P<0.05);b^(o,+)AT mRNA表达以回肠最高,十二指肠次之,空肠最低,而回肠显著高于十二指肠和空肠(P<0.05),十二指肠显著高于空肠(P<0.05).随着饲粮粗蛋白质水平的增加,饲粮干物质消化率、粗蛋白质消化率和消化能值均有提高,但未达到显著性水平(P>0.05).肉仔鸡小肠各肠段PepT1mRNA和b^(o,+)AT mRNA的表达均随饲粮粗蛋白质水平的提高而有不同程度的改善,16%CP组PepT1mRNA在十二指肠和空肠的表达显著低于20%CP组(P<0.05),其在空肠的表达显著低于18%CP组(P<0.05).20%CP组b^(o,+)AT mRNA在十二指肠和空肠的表达显著高于16%CP组(P<0.05).【结论】适宜的饲料粗蛋白质水平有利于PepT1和b^(o,+)AT mRNA的表达.

【Objective】To assess the effect of dietary crude protein level on mRNA expression of intestinal PepT1 and b（o,＋）AT of broilers.【Method】240male Cobb broilers were selected and assigned randomly into three groups,each with 8repeats and 10 birds for per repeat,and were fed the three diets with the protein level of 16%（16%CP）,18%（18%CP）and 20%（20%CP）,respectively.【Result】The average daily body weight gain,n utilization rate and metabolizable energy of 16% CP was higher than those of others（P〈0.05）,but the reverse case for Feed/Gain（P〈0.05）.There was the highest expression of PepT1 mRNA at jejunum,and the lowest at ileum,as well as jejunum was significantly higher than that at the duode-num and ileum（P〈0.05）.Bo,＋AT mRNA expression was highest in the ileum,and lowest at jejunum,and ileum was significantly higher than that in the duodenum and jejunum（P〈0.05）,and duodenum was significantly higher than that of the jejunum（P〈0.05）.With increasing of dietary crude protein level,dry matter digestibility,crude protein digestibility and digestible energy of diets w ere increased as well,but did not reach to the significant level（P〈0.05）.The expression of PepT1 and b（o,＋）AT mRNA were improved with increasing of dietary crude protein level.The expression of PepT1 mRNA at both duodenum and jejunum of 16%CP was significantly lower than those of 20%CP（P〈0.05）,and the jejunum of it was significantly lower than that of 18%CP（P〈0.05）.20%CP group had the higher expression of b（o,＋）AT mRNA in the duodenum and jejunum than that of 16%CP（P〈0.05）.【Conclusion】The results indicate that the expression of PepT1 and b（o,＋）AT mRNA could be improved by suitable dietary crude protein level.