Effects Of Diet Supplementation Of Peanut Vine And Wheat Straw On Growth Performance,Nutrient Digestibility And Rumen Microbial Diversity Of Holstein Bulls

In order to compare the effects of two kinds of roughages of peanut vine and wheat straw on the growth performance,blood biochemical index,nutrient digestibility,rumen fermentation index and rumen microflora of Holstein bulls,the following four experiments were carried out:Exp 1:The effects of feeding peanut vine and wheat straw on the growth performance and serum biochemical parameters of Holstein bulls.Eighteen Holstein bulls with a birthday age and body weight of about 485±17.98 kg were selected and randomly divided into two groups,each with 3 replicates and 3 cows each.The peanut vine group（PVG）was fed with peanut vine-based roughage,and the wheat straw group（WSG）was fed with wheat straw-based roughage.The test cattle diet consists of roughage,concentrate supplements and silage.The concentrate supplements,silage and their dosages are identical.The second stage adds 2kg/head of concentrate to the first stage.The blood was weighed and collected on the 40th and 80th day of the test period and brought back to the laboratory for analysis.The results showed that in the first stage,the average daily gain of PVG increased by 16.42%compared with WSG（P>0.05）.In the second stage,the average daily gain of PVG increased by 24.79%compared with WSG（P<0.05）.During the whole experimental period,the average daily gain of PVG increased by 20.8%compared with WSG（P<0.05）.The serum urea nitrogen（UN）concentration of PVG in serum biochemical parameters was significantly higher than that of WSG（P=0.068）,in serum alanine aminotransferase（ALT）,aspartate aminotransferase（AST）.Acreage/gluten ratio（ALT/AST）,total protein（TP）,albumin（ALB）,globulin（GLB）,white ball ratio（A/B）,glucose（GLU）,total cholesterol（CHOL）,glycerol There was no significant difference in ester（TG）,high density lipoprotein（HDLD）and low density lipoprotein（LDLD）（P>0.05）.Exp 2:Effect of feeding peanut vine and wheat straw on the apparent digestibility of nutrients in Holstein bulls.The experimental design and feed composition were the same as in Experiment 1.Three days of feed and fecal samples were continuously collected during the first sampling period and brought back to the laboratory to determine the apparent digestibility of nutrients using the acid-insoluble ash method.The results showed that the apparent digestibility of PVG in neutral detergent fiber（NDF）,acid detergent fiber（ADF）,crude protein（CP）,organic matter（OM）,calcium（Ca）and phosphorus（P）was significantly higher than WSG.（P<0.05）;there was no significant difference in the apparent digestibility of crude fat（EE）and dry matter（DM）between the two groups（P>0.05）.Exp 3:Effects of feeding peanut vine and wheat straw on rumen fermentation and microflora of Holstein bulls.The experimental design and feed composition were the same as in Experiment 1.On the 40th day of the test cycle,the rumen fluid was collected and taken back to the laboratory for ruminal fermentation index and micro flora.The rumen fluid pH and rumen ammonia nitrogen of PVG were significantly higher than WSG at the end of the first and second phases.There was no significant difference in acetic acid,propionic acid and butyric acid at the end of the first and second phases.Difference;however,at the end of the first stage of PVG,acetic acid,propionic acid,butyric acid,and the second stage of acetic acid and butyric acid were more than WSG.There was no significant difference in the abundance and diversity of rumen microbial flora between the two groups（P>0.05）.At the gate level,the relative abundance of Proteobacteria and Patescibacteria in the rumen was significantly higher than that in PVG.The relative abundance of rumen spirochaetes in PVG.Compared with WSG,there was a significant increase（P<0.05）;at the genus level,Ruminococcaceae_UCG-005.Ruminococcaceae_UCG-010,Anaeroplasma,Treponema₂,uncultured-bacterium-fp-251-o5.uncultured_bacterium_fMurIbaculaceae in the rumen of PVG,the relative abundance was significantly increased compared with the wheat straw group（P<0.05）,the rumen saccharofermentans,Ruminococcus-1,Candidatus-saccharimonas,Succinivibrionaceae_UCG-002,Christensenella in WSG ceae_R-7_group,uncultured_bacterium_oMollicutes_RF39,uncultured_bacterium_oAbscon The relative abundance of ditabacteriales SR1 was significantly higher than that of wheat straw group（P<0.05）.Exp 4:Analysis of the economic benefits of feeding peanut stalks and wheat straw to Holstein bulls.The economic benefits of the first phase of PVG are:15.02 yuan,the economic benefit of WSG is:11.02 yuan,the PVG is improved compared with WSG:36.3%;the economic benefit of the second stage peanut vine is 7.64 yuan,and the economic benefit of wheat straw group is 4.27 yuan.The PVG is improved compared with WSG:78.92%;the economic benefit of the peanut vine group is 11.33 yuan,the economic benefit of the wheat straw group is 7.53 yuan,and the PVG is improved compared with WSG:50.46%.In summary:feeding peanut vine significantly increased the daily gain,dry matter intake,apparent digestibility and economic benefits of the fattening dairy bull;the rumen environment of the peanut vine produced more ammonia nitrogen;Compared with the peanut vine group,the bacteria in the wheat straw group showed a positive correlation with the crude protein digestibility,crude fiber digestibility and rumen ammonia nitrogen concentration,and the peanut vine group was reversed.