利用体外法研究粗饲料的产气曲线及5种养分的发酵系数

IN VITRO STUDY ON GAS PRODUCTION CURVES AND INGREDIENTS FERMENTATING COEFFICIENTS OF THE FEEDSTUFF

利用自行设计的体外发酵产气装置 ,采用Jerson等[10 ] 提出的多相组合数学模型 ,获得了 9种粗饲料的产气规律曲线 ,发酵最终底物中VFA的摩尔比例及产生量 ;发酵底物中 5种养分纤维素、半纤维素、粗蛋白、淀粉和可溶性碳水化合物分别产生乙酸、丙酸和丁酸的效率 (养分发酵系数 )为 8 9、0 9、0 9、8 5、3 3、1 2、2 4、0 9、0 5、6 1、2 7、1 2、7 0、2 6、1 2mmol/ g ,且预测误差分别为 :乙酸 <14%、丙酸≤ 10 %、丁酸≤ 8%。与同类研究结果比较 ,误差范围较小 ,表明求得的养分发酵系数具有很好的应用价值。求得的粗饲料产气曲线十分理想 (R2 >0 99) ,且决定某饲料最终产气效果的主要参数是a1值的大小。

In vitro gas production apparatus and a mathematical model were used to study (1) gas production curves of the nine feedstuff,such as Alfalfa,Intermedia peasshrub,Korshinsk peashrub,Corn stalk,Slender branch sweetvetch,Lovely achnatherum,clover Sand willow and Mongolian sweetvetch;(2) the molar proportion and production amount of VFAs in the final incubation fluid when substrate concentration was 400 mg.The obtained results demonstrated:(1) Gas production curves for the nine kinds of feedstuffs calculated by Groot et al (1996) model were quite satisfied (R2>0.99).Although parameters such as a 1,k 1,c 1;a 2,k 2 and c 2 all had accurate biological meanings,only parameter a 1 played an important part in determining gas production for feedstuff;(2) Through detecting VFA production in the final incubation fluid for the nine feedstuffs with 400 mg substrate respectively,the ingredients fermentating coefficients (mmol/mg) for producing acetate,propionate and butyrate from cellulose,hemicellulose,protein,starch and soluble carbohydrate were 8.9,0.9,0.9;8.5,3.3,1.2;2.4,0.9,0.5;6.1,2.7,1.2 and 70,26,12 respectively.The results showed that predicted errors were 14%,10% and 8% for acetic,propionic and butyric acid production respectively,which were in the normal range.