Study On The Mechanism Of Dietary Carbohydrate Types Reg Ulating C₂/C₃ Ratio In Rumen Fermentation

Previous studies found that the proportion of rumen propionic acid was high when the high-concentrate diet was fed,and the proportion of rumen acetic acid was high when the high-fibre diet was fed.However,later studies found that the rumen fermentation ratio of C2/C3 was also changed by feeding the same refined/coarse ratio diet,which affected the fiber fermentation rate,regardless of the diet structure.Then whether dietary regulation of the rumen C2/C3 ratio is related to the fermentation rate of the diet.The increase of dietary degradation rate meant that the rumen microbial fermentation substrate was improved,and more carbohydrates were degraded to pyruvate and then fermented into volatile fatty acids.The main purpose of this experiment was to explore the regulation effect of the concentration of pyruvate on the ratio of ethyl to propylene in the rumen.In the first part of the experiment,the effects of different diets NDF/NFC on the C2/C3 ratio of rumen were summarized by meta-analysis.The results showed that a large number of results showed that the NFC level of the diet was increased,and the rumen C2/C3 ratio was decreased,but the results of different tests were different.It is believed that there is a significant correlation between dietary NDF/NFC and rumen C2/C3 ratio,but dietary carbohydrate structure is not a key factor in directly regulating the C2/C3 ratio of rumen fermentation.The second part of the experiment explored the effect of rumen calcium pyruvate perfusion on the C2/C3 ratio in the rumen through two groups of interactive tests.Perfusion experiment USES four sheep fistula,2 x2 interaction design,continuous feeding,calcium pyruvate perfusion concentration by high concentrate diet with low concentrate diet fermentable carbohydrates in the rumen effective degradation amount calculated difference,low concentration infusion group was 6.47 g/d,high perfusion group of 12 g/d,high concentrate diet coarse than 6:4,low concentrate diet and thick than 3:7,calcium pyruvate by constant current constant rate throughout the infusion pump.At the same time,4 sheep were selected as the control group,and 2x2 interaction design was also adopted to feedhigh-concentrate diet and low-concentrate diet separately,and to drink water freely and continuously.To observe the effects of calcium pyruvate perfusion in low-concentrate diet on rumen volatile fatty acids and rumen microorganisms.The test results show that the low concentrate diet rumen C2/C3 is higher than significantly below concentrate diet?P < 0.05?,low concentrate diet after perfusion calcium pyruvate rumen acetate concentration was not significant?P > 0.05?,the concentration of propionic acid decreased significantly?P < 0.05?,low concentration calcium pyruvate perfusion of rumen C2/C3 than influence was not significant?P > 0.05?,and high concentration of calcium pyruvate perfusion rumen C2/C3 than significantly increased?P <0.05?.Calcium pyruvate had no significant effect on the structure of rumen microorganisms.After the infusion of calcium pyruvate,the total number of microbial OTU in the rumen increased?0.1 > P > 0.05?,but the differences in species diversity and evenness were not significant?P > 0.05?.High concentrate diet rumen microbes and the other three group significant difference?P < 0.05?,the two calcium pyruvate perfusion group Succinivibrionaceae_UCG-002,Fibrobacter and Megasphaera content was significantly lower than the high concentrate group?P < 0.05?,The Lachnospiraceae_ND3007_group,prevotellaceae_ucg-003,Rikenellaceae_RC9_gut_group,Ruminococcaceae_V9D2013_group,veillonellaceae_ucg-001 and Selenomonas₃ contents were significantly higher than those in the high-concentrate group?P < 0.05?.In addition,some microorganisms were found to be high in the rumen and not affected by the diet structure and calcium pyruvate,among which Prevotella₁ was the most abundant bacteria in the rumen.Conclusion: The results showed that the rumen fermentation C2/C3 ratio was more closely related to the rumen microflora structure.The main regulatory mechanism of the rumen fermentation C2/C3 ratio is the rumen microflora structure.