酵母肽对肉兔生长性能以及脂多糖应激肉兔血清细胞因子和肝脏抗氧化能力的影响

Effects of Yeast Peptides on Growth Performance of Meat Rabbits,and Serum Cytokines and Liver Antioxidant Capacity of Lipopolysaccharide-Stressed Meat Rabbits

本试验旨在研究酵母肽对肉兔生长性能以及脂多糖(LPS)应激肉兔血清细胞因子和肝脏抗氧化能力的影响。试验分2个阶段进行。第1阶段:选取160只健康的35日龄断奶伊拉配套系肉兔,初始体重为(0.96±0.06)kg,随机分为4组(公母各占1/2),每组8个重复,每个重复5只。对照组(CON组)和LPS组饲喂基础饲粮,酵母肽组(YP组)和酵母肽缓解组(L-YP)饲喂添加100 mg/kg酵母肽的基础饲粮。第1阶段饲养试验共进行35 d,其中预试期7 d,正试期28 d。记录体重、采食量等数据并计算第1阶段试验期间肉兔的生长性能指标。第2阶段:于第1阶段结束时,LPS组和L-YP组试验兔大腿肌肉注射200μg/kg BW的LPS,CON组和YP组则注射等量生理盐水,在LPS或生理盐水注射4 h后采样,测定血清细胞因子含量以及肝脏抗氧化指标和抗氧化基因mRNA相对表达量。结果显示:1)饲粮中添加酵母肽显著增加了肉兔的平均日增重(P<0.05),显著降低了料重比(P<0.05),对平均日采食量、腹泻率和死亡率无显著影响(P>0.05)。2)饲粮中添加酵母肽显著降低了肉兔血清中白细胞介素-6(IL-6)、白细胞介素-8(IL-8)和活性氧(ROS)含量(P<0.05);LPS刺激显著增加了肉兔血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、IL-6、IL-8、转化生长因子-β(TGF-β)和ROS含量(P<0.05);酵母肽和LPS在血清TNF-α、IL-6、IL-10和TGF-β含量上有显著的交互效应(P<0.05)。在LPS刺激条件下,饲粮中添加酵母肽可以显著降低LPS应激肉兔血清中TNF-α和IL-6含量(P<0.05)。3)饲粮中添加酵母肽显著提高了肉兔肝脏中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和总抗氧化能力(T-AOC)(P<0.05),并显著降低了丙二醛(MDA)含量(P<0.05);LPS刺激显著降低了肉兔肝脏中T-AOC和GSH-Px活性(P<0.05);酵母肽和LPS对肉兔肝脏中SOD活性和SOD的mRNA相对表达量有显著的交互效应(P<0.05)。在LPS刺激条件下,在LPS刺激条件下,饲粮中添加酵母肽可以显著提高LPS应激肉兔肝脏中SOD活性和SOD的mRNA相对表达量(P<0.05)。综上所述,饲粮中添加100 mg/kg酵母肽可以提高肉兔的生长性能,并通过降低机体炎症水平、提高抗氧化能力有效缓解LPS诱导的肉兔免疫应激反应。

The purpose of this study was to investigate the effects of yeast peptide on the growth performance of meat rabbits and serum cytokines and liver antioxidant capacity of lipopolysaccharide-stressed meat rabbits.The trial was divided into two phases.Phase 1:a total of 160 healthy 35-day-old weaned Hyla line rabbits were selected with an initial body weight of(0.96±0.06)kg,and randomly divided into 4 groups(half male and half female),with 8 replicates per group and 5 rabbits per replicate.Rabbits in control group(CON group)and lipopolysaccharide group(LPS group)fed a basal diet,and those in yeast peptide group(YP group)and yeast peptide remission group(L-YP group)fed the basal diet supplemented with 100 mg/kg yeast peptide.The feeding experiment lasted for 35 days,including 7 days of pre-trial period and 28 days of experimental period.Data such as body weight and feed intake were recorded and growth performance indexes of meat rabbits during the phase 1 were calculated.Phase 2:at the end of phase 1,rabbits in the LPS group and L-YP group were intramuscularily injected with 200μg/kg BW LPS,and rabbits in the CON group and YP group were injected with the same amount of normal saline.The samples were collected 4 h after injection with LPS or normal saline,and serum cytokine content,liver antioxidant indexes and mRNA relative expression levels of antioxidant genes were measured.The results showed as follows:1)adding yeast peptide significantly increased the average daily gain and significantly decreased the feed to gain ratio of meat rabbits(P<0.05),but had no significant effects on the average daily feed intake,diarrhea rate and mortality rate(P>0.05).2)The contents of serum interleukin-6(IL-6),interleukin-8(IL-8)and reactive oxygen species(ROS)were significantly decreased by adding yeast peptide(P<0.05);lipopolysaccharide stress significantly increased the contents of serum tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),IL-6,IL-8,transforming growth factor-β(TGF-β)and ROS of meat rabbits(P<0.05);serum TNF-α,IL-6,IL-10 and TGF-βcontents had significant interactions between yeast peptide and lipopolysaccharide(P<0.05).Under lipopolysaccharide stress,adding yeast peptide significantly decreased the serum TNF-αand IL-6 contents of lipopolysaccharide-stressed meat rabbits(P<0.05).3)Adding yeast peptide significantly increased the liver superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)activities and total antioxidant capacity(T-AOC)of meat rabbits(P<0.05),and significantly decreased the liver malondialdehyde(MDA)content(P<0.05);lipopolysaccharide stress significantly decreased the liver T-AOC and GSH-Px activity(P<0.05);SOD activity and SOD mRNA relative expression level in liver had a significant interaction between yeast peptide and lipopolysaccharide(P<0.05).Under lipopolysaccharide stress,adding yeast peptide significantly increased the liver SOD activity and SOD mRNA relative expression level of lipopolysaccharide-stressed meat rabbits(P<0.05).In summary,adding 100 mg/kg yeast peptide to the diet can improve the growth performance of meat rabbits,and effectively relieve the immune stress response of meat rabbits induced by lipopolysaccharide by reducing the level of inflammation and improving the antioxidant capacity.