体外产气法评价油菜秆与玉米、豆粕的组合效应

本研究旨在探讨不同比例的油菜秆与玉米、豆粕组合对体外瘤胃发酵及其组合效应的影响。采用体外发酵法研究油菜秆与玉米(0%, 15%, 30%)、豆粕(0%, 15%, 30%)组合的体外发酵参数及其组合效应值的变化,探索优化组合效果。结果表明,随着玉米比例的增加,乙酸、丙酸、丁酸和挥发性脂肪酸生成量相应增加,乙丙比下降。当油菜秆∶玉米∶豆粕为40∶30∶30时,培养液pH,氨态氮(NH₃-N)浓度和乙丙比均极显著下降(P<0.01);48 h产气量、潜在产气量、产气速率、乙酸、丙酸、总挥发性脂肪酸(VFA)浓度和有机物消化率(OMD)均极显著提高(P<0.01)。以48 h产气量、NH₃-N、挥发性脂肪酸浓度和OMD的组合效应值以及综合组合效应值(AEs)为衡量指标,油菜秆∶玉米∶豆粕为55∶30∶15组合的正组合效应最大(P<0.01)。综上所述,在本试验条件下,油菜秆∶玉米∶豆粕为55∶30∶15组合的能氮比例较为合理,瘤胃发酵效率最高,为最优组合,可提高油菜杆的利用效率。

Evaluation of the associative effects of rape straw,corn and soybean meal using an in vitro gas production technique

This study was conducted to investigate the associative effects of different mixtures of rape straw, corn and soybean meal on rumen fermentation.Rape straw was mixed with 0%,15% and 30% proportions of corn;the straw was also mixed with soybean meal using the same proportions.The mixtures were incubated in vitro using the Reading Pressure Technique (RPT)to evaluate the best combination according to rumen fer-mentation parameters and associative effects.The results showed that with rising proportions of corn,the yield rates of acetate,propionate and volatile fatty acid (VFA)also increased,but that the ratio of acetate to propio-nate decreased.Rumen pH,NH 3-N,VFA,acetate,and the ratio of acetate to propionate of treatments with 30% corn and 30% soybean meal were significantly lower than the other treatments (P <0.01),but their total gas production,potential gas production,rate of gas production,acetate,propionate,VFA,and organic mat-ter digestibility (OMD)were higher than the other treatments (P <0.01).When the associative effects of gas production,NH 3-N,VFA,OMD and the synthetic associative effects (AEs)were used as evaluation indexes, the value of associative effects of the 30% corn and 15% soybean meal treatments were the highest (P <0.01),indicating that these mixture ratios provide the most acceptable balance of energy and nitrogen.