淀粉液化芽孢杆菌对脂多糖刺激肉鸡生长性能、肠道形态及免疫功能的影响

[目的] 本试验通过测定肉鸡生长性能、肠道形态及免疫功能,研究日粮中添加淀粉液化芽孢杆菌(Bacillus amyloliquefaciens,BA)对大肠杆菌脂多糖(LPS)诱导肉鸡免疫应激的缓解作用。[方法] 选用192只1日龄AA雄性肉鸡,采用2×2因子试验设计,主因素为免疫刺激因素(注射生理盐水或LPS溶液)和日粮因素(饲喂基础日粮或添加0.2% BA的试验日粮),每组6个重复,每重复8只,试验期为21 d。分别在16、18和20日龄给LPS组腹腔注射500μg？kg-1的LPS溶液,对照组注射等体积的生理盐水。[结果] LPS刺激导致肉鸡1~21 d平均日增体质量和平均日采食量显著降低(P<0.05),血浆髓过氧化物酶(MPO)活性和白介素1β(IL-1β)含量显著升高,空肠和回肠绒毛高度以及绒毛高度与隐窝深度比值显著降低,隐窝深度显著增加,空肠黏膜TLR4、IL-1β、IL-10以及回肠黏膜IL-1β、IL-6 mRNA表达水平显著升高(P<0.05)。日粮添加BA显著降低血浆髓过氧化物酶活性,显著降低空肠黏膜TLR4、IL-1β mRNA表达水平,显著提高回肠黏膜IL-10 mRNA表达水平(P<0.05)。日粮添加BA有效阻止LPS造成的平均日增体质量降低、饲料转化率升高以及回肠隐窝深度增加,并降低了LPS导致的血浆MPO活性和回肠黏膜TLR4 mRNA表达水平升高。[结论] 日粮添加BA可缓解LPS对肉鸡生长性能造成的不良影响与LPS刺激引起的炎性反应及肠道损伤,并改善肠道黏膜免疫状态。
[Objectives] The aim of this study was to investigate the regulating effect of dietary Bacillus amyloliquefaciens (BA) supplementation on broilers after lipopolysaccharide (LPS) challenge through determining the parameters related to growth perfor-mance,intestinal morphology and immune function.[Methods] One hundred and ninety two 1 day-old male AA broiler chickens were randomly distributed into four treatments as a 2×2 factorial experiment. The main factors were stress and diet. Each treatment consisted of six replicates with eight broilers per replicate. Broilers were intraperitoneally injected with either 500 μg LPS per kg body weight or sterile saline at 16,18 and 20 day-old.[Results] LPS challenge induced obvious decreases in average daily gain and feed intake,reductions in villus height and villus height to crypt depth ratio in both jejunum and ileum,whereas increased in myeloperoxidase (MPO) activity and interleukin-1β(IL-1β) concentration in plasma,as well as mRNA expressions of TLR4,IL-1β,IL-10 in jejunum and IL-1β,IL-6 in ileum(P<0.05). Dietary BA supplementation significantly decreased circulating MPO activity and jejunal TLR4,IL-1β expressions but increased the mRNA abundance of ileal IL-10(P<0.05). The BA obviously alleviated the LPS-induced compromised average daily gain and feed conversion ratio,and increased circulating myeloperoxidase activity,ileal crypt depth and TLR4 mRNA expression(P<0.05).[Conclusions] Dietary BA supplementation could alleviate the LPS-induced poor growth performance,inflammatory response and intestinal damage,and improve mucosal immune status on broilers