Effects Of Stirring Model On Fermentation And Microflora Of Novel Dual-flow Rumen Simulation System

Ruminant rumen peristalsis plays a vital role in rumen fermentation,feed digestion and microbial community.Therefore,based on the research results of rumen peristalsis law and mechanism in our team,the effects of stirring mode(continuous,intermittent)and rate on rumen fermentation parameters,gas production and gas composition,dietary nutrient disappearance rate,microbial protein Synthesis and effects of rumen microbial activity to optimize the operating parameters of a dual-efflux continuous culture device.Experiment 1is a stability test study of the Novel Dual-flow Continuous Rumen Simulation System(nRUSITEC)to determine the adaptation period,formal period and sampling period of the equipment.In this study,six fermenters were used and a 7-day experiment was carried out under the same operating parameters.The results showed that from the 1st to the 3rd day,the number of protozoa,pH and the number of exhaust gas were significantly decreased(P<0.01),and the number of protozoa was stable at(0.96±0.15)×10~4,and the pH was stable at 6.92±0.12 on the 4th day).,the number of exhaust gas was stable at(237±1)times,and the disappearance rate of dietary dry matter was stable at(66.98±0.33)%on the 5th day.The six fermenters in the experiment had good parallelism and strong repeatability.Therefore,it is determined that the stable period of this set of equipment is 1～3d,the test period is 4～7d,and the sampling period is 5～7d.On the basis of the experimental period,adaptation period and sampling period determined in Experiment 1,Experiment 2 adopted a 3×3 Latin square experimental design and used 6fermenters to study continuous stirring,intermittent stirring A(5 minutes stirring for 2minutes intermittently)and 6 fermenters.Intermittent agitation B(4 minutes agitation intermittent 3 minutes).Effects onRUSITEC fermentation and microflora.The results showed that the two kinds of intermittent stirring had significantly higher effects on the number of protozoa,pH,exhaust times,gas production and gas composition,ammonia nitrogen,microbial protein,total dry matter disappearance rate and the disappearance rate of each nutrient component than continuous stirring(P<0.01),the contents of total volatile fatty acids,acetic acid,propionic acid,butyric acid,and valeric acid produced by intermittent stirring were also significantly higher than those produced by continuous stirring,but had no effect on the content of acetic acid/propionic acid and isovaleric acid(P>0.05),compared with intermittent stirring B,intermittent stirring A has no effect on the change of exhaust frequency,acetic acid/propionic acid,isovaleric acid,butyric acid,isobutyric acid content,and the disappearance rate of neutral detergent fiber and acid detergent fiber(P>0.05),but other indicators were significantly higher than those of intermittent stirring B(P<0.01).At the phylum level of rumen microbiota,the relative abundance of Bacteroidetes,Firmicutes and Proteobacteria in intermittent stirring was significantly higher than that in continuous stirring(P<0.01).At the genus level of rumen microbiota,the relative abundance of Prevotella,Rikenellaceae＿RC9＿gut＿group,Ruminococcus in intermittent stirring were significantly higher than that in continuous stirring(P<0.01).Therefore,under the conditions of this experiment,stirring for 5 min and 2min intermittently is closer to the real rumen movement,and improves the degree of feed fermentation,increases the content of protozoa,increases the total gas production and VFA concentration,promotes the production of acetic acid,and reduces the production of ammonia nitrogen,to promote microbial protein synthesis and rumen microbial reproduction.