体外产气法评定辣木枝与玉米/豆粕优化组合效果

摘要

本文旨在以羊草为对照研究不同比例的辣木枝与玉米、豆粕组合,以及辣木枝替代羊草与玉米、豆粕组合对体外瘤胃液发酵及其综合组合效应(AEs)的影响.试验采用体外产气法进行辣木枝/羊草与玉米(o％、15％、30％)、豆粕(0％、10％、20％)组合(试验一)以及辣木枝替代羊草与玉米、豆粕以75∶0∶7∶18、62.5∶12.5∶8∶17、50∶25∶9∶16、37.5∶37.5∶10∶15、25∶50∶12∶13、12.5∶62.5∶13∶12、0∶75∶14∶11组合(试验二),研究发酵参数及其AEs值的变化.结果表明:试验一中随着玉米、豆粕比例的增加,微生物蛋白(MCP)与有机酸含量也增加,而乙酸/丙酸下降;辣木枝组48 h产气量(48 h GP)、产气速率(a+b)以及MCP、总挥发性脂肪酸(TVFA)、乙酸、丙酸和乙酸/丙酸极显著低于羊草组(P＜0.01),而pH极显著高于羊草组(P＜0.01);当辣木枝/羊草与玉米、豆粕的比例为75∶15∶10时,2组的AEs均表现最佳;但羊草组的AEs显著高于辣木枝组(P＜0.05).试验二中随着辣木枝比例的增加,48 hGP、氨态氮(NH3-N)浓度和有机酸含量呈下降趋势;其中37.5∶37.5∶10∶15组合的MCP极显著高于其他组(P＜0.01),AEs呈最大的正组合效应.以上结果表明,辣木枝具有成为新型粗饲料资源的潜力.%The effect of mixture of moringa branch/Leymus chinensis,corn and soybean meal on rumen fermentation and the associative effects was studied in this experiment.The mixtures were incubated in vitro using the reading pressure technique (RPT) system to evaluate the rumen fermentation parameters and the associative effects.In Expl,moringa branch or Leymus chinensis was mixed with corn at a proportion of 0,15,30 and soybean meal at a proportion of 0,10,20.The results showed that the organic acid and microbial protein(MCP) were increased,but the ration of acetate and propionate were decreased with the rise of the ratio of corn and soybean meal.The value of 48 hgas production(GP),gas production rate(a+b),MCP,total volatile fatty acid (TVFA),acetate,propionate,and the ration of acetate and propionate in the moringa branch group were significantly lower those in the Leymus chinensis group(P＜0.01),while pH was higher (P＜0.01).The associative effects (AEs) in two groups were both the best when the ratio of moringa branch or leymus chinensis,corn and soybean meal was 75∶15∶10.However the AEs in the Leymus chinensis group was much higher than that in moringa branch group (P＜0.05).In Exp2,moringa branch and Leymus chinensis were mixed with corn and soybean meal in the proportion of 75∶0∶7∶18,62.5∶12.5∶8∶17,50∶25∶9∶16,37.5∶37.5∶10∶15,25∶50∶12∶13,12.5∶62.5∶13∶12 and 0∶75∶14∶11.The 48 h GP,NH3-N and organic acids were decreased as the ratio of the moringa branch went up.The MCP in 37.5∶37.5∶10∶15 mixture group was remarkably higher than any other groups (P＜0.01),and the AEs showed the best positive associative effect.In summary,the moringa branch has a potential to be a new source of the roughages.