Effects Of Different Length Peanut Vines On Growth Performance,Nutrient Digestibility,Rumen Fermentation And Microbial Diversity Of Holstein Bulls

The purpose of this experiment is to study the effects of peanut seedlings of 5-6 cm,1.5-2 cm and 0.6-0.8 cm in length on Holstein bulls during the fattening period,on their growth performance,nutrient digestibility,rumen fermentation and rumen microflora.The following three tests were carried out:Experiment 1:The effect of peanut seedlings of different lengths on the growth performance of Holstein bulls.Thirty-six Holstein bulls with similar birth age and weight were selected,with an average weight of 533 ± 7.41 kg,and randomly divided into three groups,with 3 replicates in each group,and 4 cattle in each replicate.Long-stem peanut seedling group(LPV):fed with a diet based on 5-6 cm peanut seedlings.Mid-stem peanut seedling group(MPV):fed with 1.5～2 cm peanut seedlings as the main diet.Short-stem Peanut Seedling Group(GPV):Feed the diet mainly with 0.6～0.8cm peanut seedlings.The test diet consisted of peanut seedlings,supplements of concentrate and corn silage.The test cattle were weighed on the 30th and 60th day of the test period and the daily feed intake during the test period was recorded.The results showed that at the end of the first stage,the average daily weight gain of the GPV group was significantly higher than that of the LPV group(P<0.05),and the average daily weight gain of the MPV group was not significantly different from the other two groups(P>0.05);the average daily food intake of the GPV group The average daily feed intake of the MPV group was significantly higher than that of the LPV group(P<0.05),and there was no significant difference between the GPV group and the MPV group(P>0.05);the LPV group feed The weight ratio was extremely significantly higher than that of the MPV group and GPV group(P<0.01),and the MPV group was extremely significantly higher than that of the GPV group(P<0.01).At the end of the second stage,the average daily feed intake of the GPV group was significantly higher than that of the LPV group(P<0.05).There was no significant difference in the average daily gain between the three groups(P>0.05).Throughout the experimental period,the average daily weight gain of the GPV group was significantly higher than that of the LPV group(P<0.01)and significantly higher than that of the MPV group(P<0.05).The average daily weight gain of the MPV group was significantly higher than that of the LPV group(P<0.05);The average daily feed intake of the GPV group was significantly higher than that of the LPV group(P<0.05);the feed-to-weight ratio of the LPV group was extremely significantly higher than that of the GPV group(P<0.01),and the MPV group was significantly higher than that of the GPV group(P<0.05).Experiment 2:The effect of peanut seedlings of different lengths on the apparent digestibility of Holstein bulls.The experiment design and feed composition are the same as Experiment 1.In the final stage of the experiment,three consecutive days of ration and fecal samples were collected,and the apparent digestibility of nutrients was measured.The results showed that the apparent digestibility of EE,NDF,ADF and GE in the GPV group was significantly higher than that of the LPV group(P<0.05);the apparent digestibility of CP in the GPV group was significantly higher than that of the MPV group(P<0.05);three There were no significant differences in the apparent digestibility of DM,OM,Ca and P between the groups(P>0.05).Experiment 3:The effect of peanut seedlings of different lengths on the rumen fermentation and microbial flora of Holstein bulls.The experiment design and feed composition were the same as Experiment 1.Rumen fluid was collected on the 60th day of the experiment to detect rumen fermentation indicators and microbial flora.The results showed that there was no significant difference in the pH value of the rumen juice between the three groups(P>0.05);the ammonia nitrogen content of the GPV group was significantly lower than that of the LPV group and the MPV group(P<0.05),and the difference between the LPV group and the MPV group There was no significant difference in the content of ammonia nitrogen(P>0.05);the contents of total acid and acetic acid in the GPV group were significantly lower than those in the LPV and MPV groups(P<0.05);the butyric acid content in the GPV and MPV groups was significantly lower than that in the LPV group(P<0.05),there was no significant difference in butyric acid content between GPV group and MPV group(P>0.05);there was no significant difference in propionic acid content and ethylene-propylene ratio between the three groups(P>0.05);GPV group The abundance of rumen microflora was significantly lower than that of LPV group and MPV group(P<0.01).At the phylum level,the abundance of Bacteroidetes(Bacteroidetes)in LPV group was significantly higher than that of GPV group(P<0.05);LPV group The abundance of Proteobacteria was significantly lower than that of the GPV group(P<0.05);the abundance of Tenericutes in the LPV group was significantly higher than that of the GPV and MPV groups(P<0.05),while the GPV and MPV groups The difference between them is not significant(P>0.05).At the genus level,the abundance of succiniclasticum in the LPV group was significantly higher than that in the MPV group(P<0.05);the abundance of uncultured_bacterium_f_Bacteroidales_RF16_group in the rumen of the LPV group was extremely significantly higher than that of the GPV and MPV groups(P<0.01);The abundance of uncultured_bacterium_f_Bacteroidales_RF16_group in the GPV group was significantly higher than that in the MPV group(P<0.01);the abundance of uncultured_bacterium_f_F082(Ruminococcus)and Ruminococcaceae_NK4A214_group(Ruminococcaceae_NK4A214-_group)in the MPV group was significantly higher than that in the LPV group(P<0.05);The abundance of uncultured_bacterium_f_F082(rumenococcus)in the MPV group was significantly higher than that in the GPV group(P<0.01).In summary:Feeding peanut seedlings with a length of 0.6～0.8cm can increase the daily feed intake and average daily gain of Holstein bulls,increase the apparent digestibility of crude fat,crude fiber and energy,and affect rumen fermentation and Rumen microbial abundance,phylum and genus horizontal flora,etc.