Effects Of Supplementing Vitamin E,Organic Zinc And Organic Selenium On The Blood Index,Ruminal Fermentation And Ruminal Microbiota Of Prenatal Dairy Cows

In order to investigate the effects of supplementing vitamin E,organic selenium and zinc in the diet on blood indexes,rumen fermentation and rumen flora of transition dairy cows,40 dry dairy cows with similar parity,body condition and due date were randomly divided into two groups:control group（CG）and experimental group（EG）.The cows in the control group were fed the basic diet,and the cows in the experimental group were supplemented with 1000 IU/d vitamin E,2 mg/d organic selenium and 360 mg/d organic zinc.The cows were fed from the prepartal period until 21 days postpartum.On the 7th day before delivery and the 14th day after delivery,seven cows in each group were selected according to the principle of similar parity,calving date and body condition.The bloods were collected for the determination of blood indexes,the rumen fluids were collected for the determination of rumen fermentation parameters,and the rumen flora was determined by 16S DNA sequencing technology.The results showed:1.Under the conditions of this study,when 1000IU/d vitamin E,360mg/d organic zinc and 2mg/d organic selenium were added to the perinatal diet,the milk yield of dairy cows increase by 3.28kg/d（P<0.05）,and there were no significant effects on the biochemical indexes of dairy cows’ plasma（P>0.05）.In the prepartal period,the contents of plasma catalase of EG were significantly higher than that of CG（P<0.01）,in the postpartum period,the content of plasma glutathione peroxidase of EG were significantly higher than that of CG（P<0.1）,the contents of superoxide dismutase of EG increased（P>0.05）,and the content of plasma malondialdehyde of EG decreased（P>0.05）.The results showed that the addition of vitamin E,organic zinc and organic selenium could improve the postpartum milk yield and antioxidant capacity of dairy cows.2.The addition of vitamin E,organic zinc and organic selenium in the perinatal diet had no significant effects on the pH,volatile fatty acids and NH3-N concentration of rumen fluid of dairy cows in the early and late perinatal period（P>0.05）.3.When vitamin E,organic zinc and organic selenium were added to the perinatal diet,theα-diversity of rumen flora had no significant change except Chaol decreased significantly,and theβ-diversity of rumen flora also had no significant difference（P>0.05）.Firmicutes and Bacteroidetes are the dominant bacteria in the rumen fluid of EG and CG,accounting for 95%of the bacterial expression abundance.LEFSE analysis showed that Ruminococcus,Acetitomaculum,Blautia,Lachnoclostridium,Probable_genus₁0,Ruminococcaceae_UCG₀13,Ruminiclostridium₅,Gemmobacter,Erysipelotrichaceae_UCG₀03,Algoriphagus were mainly significantly enriched in EG;Gastranaerophilales,Ruminococcus₂ were mainly significantly enriched in CG.The rumen bacteria with significant differences in expression abundance in the EG were mainly related to carbohydrate metabolism,indicating that perinatal dietary supplementation of vitamin E,organic selenium,and organic zinc may affect carbohydrate metabolism in the rumen.4.When vitamin E,organic zinc and organic selenium were added to the perinatal diet,there were no significant differences in the α-diversity and β-diversity of the rumen flora in the postpartum period（P>0.05）.Bacteroidetes and Firmicutes were the dominant bacteria in the rumen fluid of EG and CG,and the expression abundance of Firmicutes tended to increase,while Bacteroidea tended to decrease（P>0.05）.LEFSE analysis showed that Pseudomonadales,Saccharimonadales,The expression abundance of Sporolactobacillaceae,Scopulibacillus,Mogibacterium were significantly enriched in EG;Faecalibacterium were significantly enriched in CG.The rumen bacteria with significant differences in expression abundance in the EG were mainly related to the metabolism of volatile fatty acids.In conclusion,the addition of vitamin E,organic selenium and organic zinc to the perinatal diet may affect the carbohydrate metabolism and rumen fermentation in the rumen,and improve the antioxidant capacity and milk yield of postpartum cows.