牡蛎粗多糖对免疫应激仔猪炎性细胞因子和PPARγ mRNA转录水平的影响

Effects of Oyster Crude Polysaccharides on Inflammatory Cytokine and PPARγmRNA Transcription of Weanling Piglets after Immunological Stress

本试验旨在研究牡蛎粗多糖对脂多糖(LPS)刺激仔猪产生的免疫应激是否有缓解作用。选取30头(28±1)日龄的杜洛克×长白×大白三元阉公仔猪,按体重相近的原则,随机分为5个处理组(即空白对照组,免疫应激对照组,牡蛎粗多糖高、中、低剂量组),每组6头猪。空白对照组和免疫应激对照组饲喂基础日粮,牡蛎高、中、低剂量组分别饲喂添加1.2%、0.8%、0.5%牡蛎粗多糖的基础日粮。试验饲养30d后,免疫应激对照组、牡蛎粗多糖高、中、低剂量组按体重腹腔注射100μg·kg-1的LPS,空白对照组注射等量的生理盐水。各组于注射后3h采血,ELISA检测IL-1β、IL-6和TNF-α的水平;剖检取肝、脾、肾上腺、淋巴结和胸腺,用RT-PCR检测PPARγmRNA的相对转录量。结果显示,应激对照组较其它各组炎性细胞因子(IL-1β、IL-6、TNF-α)水平均有显著提高(P<0.05),牡蛎粗多糖低、中剂量组炎性细胞因子水平无显著性差异(P>0.05),2组与空白对照组相比也无显著差异(P>0.05),但2组和空白对照组与高剂量组相比IL-6与TNF-α水平显著降低(P<0.05)。牡蛎粗多糖高、中、低剂量组和空白对照组肝、脾、肾上腺和胸腺PPARγmRNA的相对转录量较应激对照组极显著降低(P<0.01),但是淋巴结PPARγmRNA的相对转录量高于应激对照组,且低、中剂量组PPARγmRNA的相对转录量较高剂量组更趋于生理状态下空白对照组的相对转录量。LPS作为免疫原可引起断奶仔猪产生免疫应激反应,在基础日粮中添加牡蛎粗多糖可以缓解免疫应激,且添加量在0.5%到0.8%区间时缓解效果较好。

The present study evaluated whether Oyster Polysaccharides could attenuate immune challenge induced by LPS.A total of thirty Du grown and crossbred castrated piglets of 28±1d were randomly allocated into five groups(namely Blank control,Immunological stress control and Oyster polysaccharide High,Medium and Low dose group)with six replicates per group according to the principle of similar weight.Piglets fed basal diet supplemented with 0(Control)or 0.5%, 0.8%,1.2% OPS(OPS High,Medium and Low dose group)for 30days.The piglets were injected intraperitoneally with a dose of EscherichiacoliLPS(100μg·kg-1 BW)except the Blank control which were injected with the same dose of normal saline.Plasma TNF-α,IL-1βand IL-6 concentrations were measured by ELISA.Piglets were killed for collect liver,spleen,kidney,lymph nodes and thymus,the PPARγmRNA transcription of them were measured.The results showed that plasma IL-1β,IL-6and TNF-αlevel in stress control was significant increased than the other groups(P<0.05).Plasma IL-6and TNF-αlevel among Low-dose group,Medial-dose group and Blank control were not significantly different(P>0.05),but those were significant decreased compare with High-dose group(P<0.05).The OPS-supplemented piglets had highly significant decreased PPARγmRNA transcription level in Liver,spleen,kidney,and thymus compared with piglets from Stress control(P<0.01),but the OPS-supplemented piglets had greater PPARγmRNA transcription level in lymph nodes compared with piglets from Stress control.The Low-dose group,and Medial-dose group PPARγmRNA expression level was closer blank control compare with High-dose group.These results indicate that dietary supplementation of OPS was able to alleviate the immunological stress caused by LPS,and the effect of remission is better between 0.5%to 0.8%.