不同浓度黄芩苷对奶牛瘤胃体外发酵参数和养分降解率的影响OA北大核心CSTPCD

This experiment was conducted to investigate the effects of baicalin concentration on gas pro-duction,fermentation parameters and nutrient digestibility of dairy cows by extracorporeal rumen fermen-tation method.Three Holstein dairy cows(650±50 kg)with permanent fistulas were used as rumen fluid donors.The experiment was divided into 4 groups(3 replicates at every time point),and the supplemental concentrations of baicalin were 0 g·kg-1(control A),0.1 g·kg-1(group B),1 g·kg-1(group C)and 2 g·kg-1(group D),respectively.Gas production,volatile fatty acid(VFA),ammoniacal nitrogen(NH3-N),pH,dry matter(DM)digestibility,neutral detergent fiber(NDF)digestibility and acid detergent fi-ber(ADF)digestibility were determined after extracorporeal fermentation for 2 h,6 h,12 h,24 h and 48 h,respectively.The results showed as follows:(1)with the increase of fermentation time,the gas pro-duction of each group showed an upward trend,and the gas production of each experimental group at each time point was significantly lower than that of the control group A(P＜0.05).(2)After adding baicalin,the dry matter degradation rate of fermentation substrate in each test group at 2 h and 48 h was significant-ly higher than that in control group A(P＜0.05);the degradation rate of neutral detergent fiber in each test group at 6 h and 12 h was higher than that of control group A(P＜0.05);the degradation rate of acid detergent fiber in each test group was higher than that of control group A(P＞0.05)from 2 h to 24 h,with the effect of 1 g·kg-1 concentration the most effective.(3)During the whole fermentation cycle,the pH of each experimental group at each time point was higher than or similar to that of the control group A,and with the increase of baicalin concentration,the pH increased first and then decreased.The contents of acetic acid and TVFA in test group C and D were significantly higher than those in control group A(P＜0.05),and the content of butyric acid in test group B and C were higher than those in control group A at 2 h and 12 h of fermentation(P＜0.05).(4)The NH3-N content of each test group was lower than that of control group A within 48 h of fermentation(P＞0.05).In conclusion,based on the above analysis,the optimum supplemental concentration of baicalin in vitro rumen fermentation of dairy cows is 1 g·kg 1 under the conditions of this experiment.