Effects Of Grape Seed Extract On Lactational Performance,energy Metabolism And Rumen Microbiome In Dairy Cows During Periparturient Period

During the perinatal period,the disease incidence of dairy cows is significantly higher than other times.Statistically,75 % illnesses of cows occur in the first month after calving,and 36% of deaths occur in the 60 days after calving.Therefore,reducing the morbidity of cows in the perinatal period is the fundamental method that saving the cost and improving the efficiency of breeding cows in dairy farming.The rumen is the main organ for decomposing fodder and absorbing nutrients in cows,and the rumen microbiota are the executors of plant fermentation.An increasing number of researches have shown that abundance and structure change of rumen microbiota are closely related to lactational performance and disease occurrence of dairy cows.Recent years,it has been found that extracts of a variety of plants or their fruits can significantly improve the structure of rumen microbiota,which can enhance the production performance of dairy cows.In vitro,a large number of studies indicated that procyanidin(PR),the main component of grape seed extract(GE),can significantly improve toxicant or drug overdose-caused oxidative damage and inflammation in hepatocytes and mammary epithelial cells.However,whether the GE,as feed additive,can regulate energy metabolism and lactational performance of perinatal cows,which is rarely reported.Thus,the objective of this study was to investigate the effects of GE on lactational performance,energy metabolism and microbiota and fermentation of rumen in dairy cows during periparturient period,as well as the possible mechanisms,which to lay a theoretical foundation for the development of GE related feed additives.Firstly,to evaluate the safety of GE,acute and subacute oral toxicity tests were performed on Kunming rats.The results showed that it did not affect the body weight and functional indictors of liver and kindey when the mice gavage 10 g/kg GE Secondly,to evaluate whether the GE was safety for cows,10 cows were selected and randomly divided into negative control group(NC,N = 5)and treatment group(N = 5).The cows of NC were given a gavage saline and treatment group were given a gavage of GE [0.1%of dry matter intake(DMI)] that dissolved in saline for 7 days.To detecte the functional indexes of liver and kidney,the blood samples were collected by a coccygeal venipunctur.The results showed that there was no significant difference between functional indexes of the liver and kidney of dairy cows in the GE and the NC.Therefore,it is safe for GE to feed perinatal cows.To investigate the effects of GE on lactational performance,energy metabolism and microbiota and fermentation of rumen in dairy cows during periparturient period,60 perinatal cows were randomly divided into the NC group(N = 30)and supplementary GE group(GE;N = 30).The NC group was fed ordinary diet and the GE group was fed 1g GE per kg of total mixed ration.The whole experiment was performed for 51 days,from 21 days before to 30 days after calving.The incidence of disease and milk production of cows were observed and recorded daily during feeding.To detecte the related functional indexs,the blood and milk samples were collected at-7 before and 7,14,21,28 and 31 day after calving.The results showed that DMI,milk yield,lactose,milk fat,milk protein and blood glucose of dairy cows feed with GE for51 days during periparturient period,were higher than those in NC groups but the serum free fatty acids(FFA)and β-hydroxybutyric acid were significantly lower.Compaired with NC group,the activities of aspartate aminotransferase(AST),alanine aminotransferase(ALT)and ornithine carbamoyl transferase(OCT)and the content of interleukin-6(IL-6),IL-8,tumor necrosis factor-α(TNF-α),lipopolysaccharide(LPS)and histamine in serum were significantly lower in GE group.Compared with NC group,the expression of inflammatory signaling pathway related protein phosphorylated nuclear factor kappa B(p-NF-κB)in GE group was lower but inhibitor of kappa Bα(IκBα)was higher.In addition,the content of malonaldehyde(MDA)of serum in the GE group was significantly lower than NC,whereas the activities of superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-Px)and the abundance of nuclear factor E2-related factor 2(NRF2)signaling pathway related proteins in liver tissue were significantly higher than those in NC.Importantly,the occurrence of clinical ketosis,subclinical ketosis,clinical metritis,subclinical mastitis,subclinical hypocalcemia,clinical hypocalcemia and retained placenta in GE group were significantly lower than NC.Therefore,these results indicated that GE supplementation improved the lactation performance,significantly alleviated liver injury and inflammatory,enhanced capacity of antioxidant and reduced the occurrence of diseases in perinatal cows.To investigate the effects of GE on microbiota and fermentation of rumen in dairy cows,10 rumen fluids(NC = 5;GE = 5)were selected to perform 16 s r RNA sequencing and targeted metabolic sequencing.The results showed that GE supplementation significantly increased the abundance of rumen microbiota and the contents of acetate,propionate,butyrate,isobutyrate,valerate and total volatile fatty acid(TVFA),whereas decreased the ratio of acetate to propionate and the content of LPS and histamine.The genus levels of rumen microbiota were analyzed by Wilcoxon rank-sum test.The results showed that the Propionibacterium,Bifidobacterium,Veillonella,Prevotellaceae and Butyrivibrio were significantly higher in GE than NC group.However,the abundance of Clostridia,Lactobacillus,Eggerthellaceae,Acinetobacter,Sphaerochaeta,Streptococcus,Erysipelotrichaceae,Syntrophococcus,undefined(Gastranaerophilales,UCG-010,UCG-002 and Chloroplast)and Escherichia-Shigell bacteria were lower than NC group.The correlation between the different microbiota of NC and GE groups at the genus level with fermentation of rumen in dairy cows during periparturient period were performed.The results revealed that the content of propionate in rumen fluid was positively correlated with Propionibacterium and Veillonellaceae.The content of valerate was positively correlated with the abundance of Veillonellaceae and Bifidobacterium.In addition,the content of LPS in rumen fluid was positively correlated with the abundance of Succinivibrionaceae＿UCG-002,Acinetobacter,Gastranaerophilales and UCG-010,whereas there was a negative correlation trend(difference was not significant)with Bifidobacterium,Veillonellaceae and Propionibacterium.Then,the correlation between the different microbiota with lactational performance,energy metabolism and related indictors of serum in dairy cows during periparturient period were performed.The results indicated that milk production was positively correlated with the abundance of Prevotellaceae and Butyrivibrio,but serum FFA content was negatively correlated with the abundance of Propionibacterium.In addition,indexs of liver damage(ALT and AST activities)and inflammation related index(TNF-α)content of serum were positively correlated with the abundance of Acinetobacter,Succinivibrionaceae,Elusimicrobium,Streptococcus and Gastranaerophilales,whereas were negatively correlated with Bifidobacterium and Propionibacterium.Furthermore,the SOD activity of serum was positively correlated with the abundance of Bifidobacterium and Propionibacterium.These results indicated that GE may inprove the liver injury,systemic inflammation and oxidative stress of dairy cows by regulating rumen microbiota.Togetherly,these results indicated that GE supplementation significantly increased the abundance of VFA-producing bacteria in rumen,thereby increasing the content of VFA,as precursor of glucose,which alleviated the negative energy balance of perinatal cows and reduced incidence of metabolic diseases.In addition,GE supplementation ameliorated the liver damage and enhanced the capacities of anti-inflammatory and antioxidant in dairy cows,which may be the reason for the decreased occurrence of metabolic and infectious diseases during perinatal period.Therefore,regulation of rumen microbial structure and increase of the abundance of beneficial bacteria can prevent the occurrence of diseases in perinatal cows;besides,GE may be used as a feed additive to improve the quality and efficiency of perinatal cows.