苜蓿皂苷提取物对断奶湖羊免疫、抗氧化能力和瘤胃微生物区系的影响

Effects of Alfalfa Saponin Extract on Immunity,Antioxidant Capacity and Rumen Microflora of Weaned Hu Sheep

【目的】苜蓿皂苷作为一类天然生物活性物质,具有提高畜禽机体免疫力、促生长及调节胃肠道功能等多方面效用。试验旨在探究苜蓿皂苷提取物对断奶湖羊生长性能、免疫功能、抗氧化能力和瘤胃微生物区系的影响。【方法】选取45日龄、体重相近(15.67 kg±1.18 kg)的断奶湖羊32只,随机分为2组,每组4个重复,每个重复4只羊。对照组(CON)湖羊饲喂基础饲粮,皂苷组(AS)湖羊在基础饲粮中添加2 g/kg(饲粮干物质基础)苜蓿皂苷提取物,预试期7 d,正试期60 d。试验结束后收集断奶湖羊瘤胃液测定微生物组成,采集颈静脉血用于测定血清免疫和抗氧化性能相关指标。【结果】(1)两组湖羊平均日增重(ADG)和料重比(F/G)均无显著差异(P>0.05)。(2)与对照组相比,皂苷组湖羊血清中免疫球蛋白(IgA、IgM)、抗炎因子白介素-10(IL-10)、CD4^(+)T细胞和CD4/CD8水平极显著或显著升高(P<0.01;P<0.05),而促炎因子肿瘤坏死因子-α(TNF-α)、IL-6含量均极显著降低(P<0.01)。(3)与对照组相比,皂苷组湖羊血清中总抗氧化能力(T-AOC)显著升高(P<0.05),而丙二醛(MDA)含量极显著降低(P<0.01)。(4)两组间湖羊瘤胃液pH、氨态氮(NH3-N)、各挥发性脂肪酸和总挥发性脂肪酸(TVFA)浓度均无显著差异(P>0.05)。(5)两组间湖羊Shannon指数、Simpson指数和主坐标分析(PCoA)均无明显差异;在属水平上,皂苷组湖羊瘤胃液中硫酸盐还原菌脱硫弧菌属(Desulfovibrio)和有益菌罗氏菌属(Roseburia)、凸腹真杆菌群(Eubacterium_ventriosum_group)等的相对丰度均显著高于对照组(P<0.05)。【结论】饲粮中添加苜蓿皂苷提取物可以影响断奶湖羊瘤胃微生物的组成,提高机体免疫和抗氧化能力,且一定程度上有利于机体健康。

【Objective】As a natural bioactive substance,alfalfa saponins have many effects,such as improving immunity,promoting growth,and regulating the gastrointestinal function of livestock and poultry.The experiment was aimed to investigate the effects of alfalfa saponin extract on the growth performance,immune function,antioxidant capacity and rumen microflora of weaned Hu sheep.【Method】Thirty-two 45-day-old weaned Hu sheep with similar body weight(15.67 kg±1.18 kg)were randomly divided into 2 groups with 4 replicates per group and 4 sheep per replicate.Hu sheep in control group(CON)were fed a conventional diet,and Hu sheep in saponins group(AS)were fed a basal diet supplemented with 2 g/kg(dry matter basis of the diet)of alfalfa saponin extract.The pre-trial period was 7 days,and the trial period was 60 days.At the end of the experiment,the rumen fluid of weaned Hu sheep was collected to determine the microbial composition,and the jugular vein blood was collected to determine the serum immune,and antioxidant performance-related indicators.【Result】①There was no significant difference in average daily gain(ADG)and feed/gain(F/G)between CON and AS groups of Hu sheep(P>0.05).②Compared with CON group,the levels of immunoglobulin(IgA and IgM),anti-inflammatory factor interleukin-10(IL-10),CD4^(+)T cells,and CD4/CD8 in serum of Hu sheep in AS group were extremely significantly or significantly increased(P<0.01 or P<0.05),while the levels of pro-inflammatory factors tumor necrosis factor-α(TNF-α)and IL-6 were extremely significantly decreased(P<0.01).③Compared with CON group,the total antioxidant capacity(T-AOC)in serum of Hu sheep in AS group was significantly increased(P<0.05),while the content of malondialdehyde(MDA)was extremely significantly decreased(P<0.01).④There were no significant differences in rumen fluid pH,ammonia nitrogen(NH 3-N),volatile fatty acids,and total volatile fatty acids(TVFA)concentrations between CON and AS groups(P>0.05).⑤There was no significant difference in Shannon index,Simpson index,and principal coordinate analysis(PCoA)between CON and AS groups.At the genus level,the relative abundance of sulfate-reducing bacteria Desulfovibrio,beneficial bacteria Roseburia,Eubacterium_ventriosum_group,etc.in rumen fluid of Hu sheep in AS group was significantly higher than that in CON group(P<0.05).【Conclusion】Adding alfalfa saponin extract to the diet could affect the composition of rumen microorganisms in weaned Hu sheep,improve the body’s immunity and antioxidant capacity,and was beneficial to the health of the body to a certain extent.