Effects Of Yeast Culture On Goat Rumen Fermentation,Nutrient Degradation Rate And Rumen Microorganisms In Rations With Different ADF Levels

The experiment aimed to explore the effects of different levels of acid detergent fiber(ADF)and yeast culture(YC)on rumen fermentation(pH,volatile fatty acids and gas production),dietary nutrient disappearance rate,and microflora in vitro,and three 1-year-old Jilin native goats(30±2.5kg)were selected as the experimental animals.This experiment used a 3×3 full factor experiment design with three levels of ADF(16%,18.5%,and 21%)and 0%,3%,and5% YC were supplied,respectively.RFS gas production machine and Dairy Ⅱ(ANKOM i)were used measure fermentation parameters and others indexes on 6h,12 h,24h,30 h,36h,48 h.The experimental results were as follows:Experiment 1: With the decreasing of the ADF in diet,the concentration of acetic acid,propionic acid,total volatile fatty acid(TVFA)and ammonia nitrogen(NH3-N)were significantly increased(P<0.05)on 30h;18.5% and 21% ADF diet supplied with YC increased the content of acetic acid,propionic acid and TVFA on 30 h,which were significantly lower than those of the 16% ADF diet groups(P<0.05);There was no interaction of ADF and YC for the pH,acetic acid,NH3-N and gas production(P<0.05).Both the dietary dry matter degradation rate and the NDF degradation rate decreased with the increasing of the level of ADF(P<0.05).Diet supplied with YC can significantly increase the dry matter degradation rate and NDF degradation rate in the middle and high levels of ADF diet(P<0.05).Experiment 2: 16 s DNA high-throughput sequencing was used to determine the rumen microflora on the 24 h in vitro.The results showed that the levels of ADF and YC significantly affected the microflora(P<0.05).With the increasing of ADF in diet,the abundance of lunomonas＿1,Erysipelotrichaceae＿UCG＿004,Prevotaceae＿UCG-001 and F082(P<0.05),Quininella.Genus and Prevotella＿UCG-003 increased;Diet supplied with YC significantly increased the abundance of Prevotella,Rumenococcus and Succinobacterium(P<0.05),which was increase with the level of YC increasing.Conclusion: The addition of YC has no effect on the rumen fermentation and dry matter disappearance rate of the 16% ADF diet group,and it can significantly increase the NDF disappearance rate.Two YC supplements can improve the rumen fermentation effect of 18.5%and 21% ADF diet groups.For the 18.5% ADF diet group,the effect of 1% supplementation is better than 1.5%.For the 21% ADF diet group,there is little difference between the two doses in promoting effects,and the addition of YC has a significant impact on the rumen microflora.