生物蛋白API对肉鸡生长性能和肠道健康的影响

Effects of Bioengineering Protein API on Growth Performance and Gut Health of Broilers

【目的】旨在探讨不同水平生物蛋白API(artificial parasin I protein,含鲶鱼抗菌肽parasin I功能片段的基因工程蛋白)添加对肉鸡生长性能和肠道健康的影响。【方法】将450羽1日龄爱拔益加(AA)肉鸡随机分为5组,对照组饲喂基础饲粮,试验组在基础饲粮中分别添加API 250、500、750、1000 mg/kg。每组10个重复,每个重复9只鸡,试验期为42 d。【结果】(1)API添加一定程度提高了鸡只末重,其中500 mg/kg API组鸡只末重较对照组提高了79.62 g/只(P>0.05)。(2)API添加降低了空肠隐窝深度并增加了其绒隐比(P<0.05),且结果呈二次线性变化(P=0.008),但对十二指肠和回肠的组织形态无显著影响(P>0.05)。(3)API添加具有提高空肠黏膜中α-淀粉酶活性的趋势(P=0.090),其中500 mg/kg API组α-淀粉酶活性最高;α-淀粉酶活性与API添加水平呈二次线性变化(P=0.033)。(4)API添加增加了盲肠中总菌数量(P<0.01),其中750 mg/kg API添加降低了大肠杆菌数量(P<0.05)且增加了乳酸杆菌数量(P<0.01);结果均与API添加水平呈二次线性相关(P<0.01)。(5)1000 mg/kg API添加上调了空肠中OCLN的表达丰度(P<0.05);500和750 mg/kg API添加下调了十二指肠中TNF-α的表达丰度(P<0.05);API添加上调了空肠中IL-10的表达(P<0.05),下调了空肠TNF-α(P<0.01)和IFN-γ(P<0.05)的表达。【结论】API通过改善肉鸡肠道形态屏障功能,提高肠道消化酶活性,进而促进肠道健康。总体来看,本试验条件下API添加以750 mg/kg对鸡只肠道健康的改善效果较好。

【Objective】This study aims to investigate the effects of different levels of bioengineering protein API(Artificial parasin I protein,contains catfish antimicrobial peptide parasin I functional fragment)supplementation on growth performance and intestinal health of broilers.【Method】4501-day-old Arbor Acres(AA)broilers were randomly divided into 5 groups with 10 replicates per group and 9 individuals in each replicate.The control group was fed with the basal diet(BD),and the experimental groups were supplemented with 250,500,750,1000 mg/kg of API.The trial lasted for 42 d.【Result】①The API supplementation improved the final body weight of chickens and 500 mg/kg API group improved by 79.62 g/bird compared with the control group(P>0.05).②API supplementation decreased the jejunal crypt depth and increased its chorionic to crypt ratio(P<0.05),while had no impact on the histodomorphology of the duodenum and ileum(P>0.05),and exhibited a quadratic linear change tendency(P=0.008).③The API supplementation tended to increase theα-amylase activity in jejunal mucosa(0.05<P<0.1),and 500 mg/kg API group had the highestα-amylase activity and showed a quadratic linear change in response to levels of API supplementation(P=0.008).④API supplementation increased the number of total bacteria in the cecum(P<0.01),and 750 mg/kg API supplementation decreased the number of Escherichia coli(P<0.05)and increased the number of Lactobacillus.The results were all quadratic linearly correlated with the level of API supplementation(P<0.01).⑤API supplementation had limited effect on the mRNA abundance of ZO-1,CLDN-1,OCLN and MUC2 in duodenum,jejunum and ileum(P>0.05);500 and 750 mg/kg API supplementation down-regulated the expression abundance of TNF-αin the duodenum(P<0.05);API addition up-regulated the expression abundance of IL 10 in the jejunum(P<0.05)and down-regulated the expression abundance of TNF-αin the jejunum(P<0.05),and the expression abundance of IFN-γ(P<0.05).【Conclusion】API can improve the intestinal morphological barrier and digestive enzyme ability,and then promote intestinal health of broilers.In general,750 mg/kg API supplementation exhibits better promoting effect on intestinal health of chickens in present study.