辣椒碱对泌乳前期奶牛产奶性能、血清生化指标、瘤胃微生物及代谢组的影响

Effects of Capsaicin on Milk Performance,Serum Biochemical Indices,Rumen Microorganism and Metabonomic in Early Lactation Dairy Cows

本试验旨在研究辣椒碱对泌乳前期奶牛产奶性能、血清生化指标、瘤胃微生物及代谢组的影响。选择年龄、胎次、泌乳日龄及产奶量相近的40头荷斯坦奶牛,随机分为对照组和试验组,每组5个重复,每个重复4头牛。对照组奶牛饲喂原奶牛场饲粮,试验组在此基础上每头添加1.2 g/d的辣椒碱,每天饲喂3次,预试期7 d,正试期2个月。每天记录投料量和剩料量,测定干物质含量,计算干物质采食量;试验第1、15、30、45、60天时,分别记录产奶量并采集奶样,测定乳成分;试验第1、60天时,牛尾根采血10 mL,离心后取上清,测定血清生化指标;试验第60天时,每个重复中随机挑选1头试验牛采集瘤胃液,测定发酵参数、微生物区系及代谢组学,每组5头,共计10头。结果显示:辣椒碱能够促进泌乳前期奶牛产奶量(P<0.05),4%标准乳含量在试验第60天后有显著升高(P<0.05);与对照组相比,在试验第30、45天时,试验组乳脂率显著下降(P<0.05),而干物质采食量、乳糖率、乳蛋白率、乳总固体含量无显著变化(P>0.05);辣椒碱对泌乳前期奶牛血清谷胱甘肽抗氧化物酶和超氧化物歧化酶活性均无显著影响(P>0.05);试验组血清β-羟丁酸、多巴胺含量显著升高(P<0.05),胆囊收缩素含量显著降低(P<0.05),对胰岛素含量无显著影响(P>0.05)。此外,辣椒碱对泌乳前期奶牛瘤胃发酵参数无显著影响(P>0.05);但改变了瘤胃微生物组成,与对照组相比,试验组厚壁菌门相对丰度显著升高(P<0.05);琥珀酸弧菌UCG-001相对丰度显著下降(P<0.05),瘤胃球菌科UCG-014属与瘤胃球菌科RC9肠道群相对丰度显著升高(P<0.05)。检测发现45个差异代谢物,富集差异显著的代谢通路有万古霉素的生物合成及维生素B_(6)的新陈代谢(P<0.05)。综上所述,辣椒碱具有促进泌乳前期奶牛产奶的潜力,能够通过改变瘤胃菌群结构,影响瘤胃代谢物含量,改善瘤胃内环境。

This experiment was conducted to study the effects of capsaicin on milk performance,serum biochemical indices,rumen microorganism and metabonomic of early lactation dairy cows.Forty Holstein cows with similar age,parity,lactation age and milk yield were randomly divided into control group and experimental group,with 5 replicates in each group and 4 cows in each replicate.The control group was fed a raw dairy diet,and the experimental group was fed 1.2 g/d capsaicin three times a day.The pre-test period was 7 days and the test period was 2 months.The amount of feed and residual feed were recorded every day,and the dry matter content in the diet was determined to calculate the dry matter intake;on the 1st,15th,30th,45th and 60th day of the experiment,milk yield was recorded and milk samples were collected to determine milk composition;on the 1st and 60th day of the experiment,10 mL blood was collected from the root of cow’s tail,and the supernatant was taken after centrifugation to determine serum biochemical indexes;on the 60th day of the experiment,one cow in each replicate was randomly selected to collect rumen fluid to determine fermentation parameters,microflora and metabolomics,with 5 cows in each group,a total of 10 cows.The results showed that capsaicin could promote the milk production of early lactation cows(P<0.05),and 4%standard milk increased significantly after the 60th day of the experiment(P<0.05).Compared with the control group,on the 30th and 45th day of the experiment,the milk fat rate of the experimental group decreased significantly(P<0.05),while the dry matter intake,lactose rate,milk protein rate and total solids content of milk had no significant changes(P>0.05).Capsaicin had no significant effect on serum glutathione antioxidant enzyme and superoxide dismutase activities of dairy cows at early lactation stage(P>0.05);the contents of serumβ-hydroxybutyric acid and dopamine in experimental group were significantly increased(P<0.05),cholecystokinin content was significantly decreased(P<0.05),and there was no significant effect on insulin content(P>0.05).In addition,capsaicin had no significant effect on rumen fermentation parameters of dairy cows at early lactation stage(P>0.05),but changed rumen microbial composition.Compared with the control group,the relative abundance of Firmicutes in the experimental group was significantly increased(P<0.05),and the relative abundance of Succinivibrionaceae UCG-001 was significantly decreased(P<0.05).The relative abundance of Ruminococcaceae UCG-014 and Rikenellaceae RC9 gut group were significantly increased(P<0.05).Forty-five different metabolites were detected,the biosynthesis of vancomycin and the metabolism of vitamin B_(6) were the metabolic pathways with significant enrichment differences(P<0.05).In conclusion,capsaicin has the potential to promote milk production in early lactation,it can improve the rumen environment by changing the structure of rumen microflora,affecting the content of rumen metabolites.