Effects Of Capsaicin On Performance,Serum Biochemistry,Rumen Microflora And Metabonomics Of Lactating Dairy Cows

In recent years,people’s demand for dairy products has been increasing with the improvement of residents’ quality of life.Heat stress in summer and lack of energy supply after delivery are two major problems in dairy farming,which directly affect the production efficiency and healthy breeding of dairy cows.Capsaicin(CAP)is an important component and functional substance in the active extract of Capsicum.A large number of medical studies have reported that it has anti-cancer,anti-oxidation,antibacterial and analgesic functions.In animal experiments,some studies have shown that capsaicin can improve animal immunity,skin color and feed return.Therefore,this experiment was conducted to study the effects of capsaicin on the production performance,serum biochemistry,rumen microflora and metabonomic of lactating dairy cows by feeding them with capsaicin in summer heat stress dairy cows and early lactation dairy cows after parturition.It is expected to solve the two problems of heat stress and negative energy balance in the process of dairy farming from the perspective of nutrition regulation,and provide scientific basis for the development and application of capsaicin in dairy production.Experiment 1 Effects of capsaicin on feed intake,milk production performance and serum biochemical indexes of heat stressed dairy cowsIn this experiment,40 healthy Holstein cows with good health,middle lactation stage,lactation days(150 ± 5.23 days),average weight(584 ± 10.29 kg)and parity(2 ± 0.91)were selected.They were randomly divided into control group and experimental group,20 in each group.The control group was fed with the original dairy farm diet,and the experimental group was fed with 1.2 g/d capsaicin on the basis of the original diet for 2 months.At the beginning and end of the experiment,10 m L of blood was collected from the root of oxtail,and the supernatant was taken after centrifugation to determine blood glucose,antioxidant enzymes,malondialdehyde,cortisol and other indicators.The results showed that capsaicin could reduce rectal temperature(P<0.05),promote feeding(P<0.05),and reduce the number of milk somatic cells(P<0.05).But capsaicin had no significant effect on milk yield,milk fat rate,lactose rate and milk protein rate(P>0.05).In addition,dietary capsaicin supplementation could reduce serum creatine kinase,cortisol and malondialdehyde concentrations(P<0.05),but had no significant effect on serum glutathione peroxidase and superoxide dismutase(P>0.05).Adding capsaicin to the diet of dairy cows with heat stress in summer can promote feeding and improve the ability of dairy cows to alleviate heat stress.Experiment 2 Effects of capsaicin on production performance,serum biochemistry,rumen microorganism and metabonomics of early lactation dairy cowsIn this experiment,40 pre lactation cows with similar age(2.9 ± 0.9),parity(1.9 ± 0.9)and milk yield(35.57 ± 2.57 kg)were randomly divided into control group and experimental group,with 20 cows in each group.Each group was divided into 5 replicates,with 4 cows in each replicate.The control group was fed the original dairy formula diet,and the experimental group was added 1.2g/d capsaicin(mixed with a small amount of corn flour or DDGS)on the basis of the original dairy diet for 2 months.At the beginning and end of the experiment,blood samples were collected from tail vein to determine serum biochemical indexes.On the last day of the experiment,one cow was selected from each replicate to collect rumen fluid,5 cows in each group.The results showed that capsaicin could promote the milk production of early lactation cows(P<0.05),and 4% standard milk increased significantly after 60 days of treatment(P<0.05).Compared with the control group,the milk fat rate of the experimental group decreased significantly after 30 and 45 days of treatment(P<0.05),while the dry matter intake,lactose rate,milk protein rate and total solids of milk had no significant changes(P>0.05).Capsaicin had no significant effect on the activities of glutathione antioxidant enzyme and superoxide dismutase in pre lactation cows(P<0.05);compared with the control group,the contents of serum β-hydroxybutyric acid and dopamine in capsaicin group were significantly increased(P<0.05),and cholecystokinin was significantly decreased(P<0.05);there was no significant effect on insulin level in capsaicin group(P>0.05).Capsaicin had no significant effect on the contents of total protein,albumin,total cholesterol,triglyceride and glucose in serum of pre lactation cows(P>0.05).In addition,capsaicin had no significant effect on rumen fermentation parameters and microbial diversity(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),while the relative abundance of other genera had no significant change(P>0.05).A total of 45 different metabolites were detected,and four main metabolic pathways were found by enrichment analysis(P<0.05),including biosynthesis of vancomycin group antibiotics,bisphenol degradation,vitamin B6 metabolism,and metabolism of fructose and mannose.In conclusion,capsaicin can significantly improve the milk yield of early lactation cows,and has the function of improving the rumen environment.