Park Jae Hong, Lee Sang In, Kim In Ho
Department of Animal Resource and Science, Dankook University, Cheonan 31116, Korea.
Department of Animal Biotechnology, Kyungpook National University, Sangju 37224, Korea.
J Anim Sci Technol. 2020 Sep;62(5):614-627. doi: 10.5187/jast.2020.62.5.614. Epub 2020 Sep 30.
During the course of this trial, our team assessed the influence of protease upon the growth performance, the nutrient digestibility, and the expression of growth-related genes and amino acid transporters within the liver, muscle, and small intestines of broilers. During the first step, our team allocated 600 broilers into four dietary treatments for a period of 35 days in order to measure the growth performance and nutrient digestibility of the broilers selected. The separate treatments contained 10 replicates (15 birds per replicate). The treatments were composed of: 1) CON, basal diet; 2) T1, basal diet + 0.03% protease; 3) T2, basal diet + 0.06% protease; and 4) T3, basal diet + 0.09% protease. Next, the broiler chick sample tissue was harvested from the CON and T3 groups in order to conduct gene expression analysis following the feeding trials the broilers underwent. Our team discovered that the broilers fed protease diets possessed increased body weight and an average daily gain, but conversely, had lower feed conversion ratios when their dietary protease levels increased from 0% to 0.09% ( < 0.05). Additionally, significant linear improvements were identified among the nutrient digestibility of dry matter, crude protein, energy, and amino acids within broilers supplied with protease diets when contrasted and compared with broilers supplied with the basal diet ( < 0.05). In addition, the gene expression of the genes , and in the liver, and the genes and in the breast muscles, was significantly increased after broilers were fed with a protease diet as compared to broilers that subsisted on a basal diet ( < 0.05). Protease supplementation also raised the expression levels within these amino acid transporters: , and , located in the small intestine, when compared to the basal diet ( < 0.05). Our results suggest that protease supplementation in their diet improved the growth performance of broilers via an increase in the expression growth-related genes within broiler liver and muscle tissue. In addition, protease supplementation enhanced broiler digestibility via the upregulation of amino acid transporter expression within the small intestine.
在本次试验过程中，我们的团队评估了蛋白酶对肉鸡生长性能、养分消化率以及肝脏、肌肉和小肠中生长相关基因和氨基酸转运蛋白表达的影响。第一步，我们的团队将600只肉鸡分为四种日粮处理组，为期35天，以测量所选肉鸡的生长性能和养分消化率。每个处理组有10个重复（每个重复15只鸡）。处理组包括：1）CON，基础日粮；2）T1，基础日粮+0.03%蛋白酶；3）T2，基础日粮+0.06%蛋白酶；4）T3，基础日粮+0.09%蛋白酶。接下来，在肉鸡进行饲养试验后，从CON组和T3组采集肉鸡雏鸡样本组织，以进行基因表达分析。我们的团队发现，当日粮蛋白酶水平从0%增加到0.09%时，饲喂蛋白酶日粮的肉鸡体重和平均日增重增加，但相反，饲料转化率较低（P<0.05）。此外，与饲喂基础日粮的肉鸡相比，饲喂蛋白酶日粮的肉鸡在干物质、粗蛋白、能量和氨基酸的养分消化率方面有显著的线性改善（P<0.05）。此外，与以基础日粮为生的肉鸡相比，饲喂蛋白酶日粮的肉鸡肝脏中的基因、和，以及胸肌中的基因和的基因表达显著增加（P<0.05）。与基础日粮相比，补充蛋白酶还提高了位于小肠中的这些氨基酸转运蛋白、和的表达水平（P<0.05）。我们的结果表明，在日粮中补充蛋白酶可通过增加肉鸡肝脏和肌肉组织中生长相关基因的表达来提高肉鸡的生长性能。此外，补充蛋白酶通过上调小肠中氨基酸转运蛋白的表达来提高肉鸡的消化率。
