苜蓿与玉米秸秆不同比例混合草颗粒营养价值评价

摘要

利用体外发酵方法,对不同配比苜蓿与玉米秸秆的组合效应进行研究.结果表明:(1)混合草颗粒的比例对体外发酵液pH值影响显著(P<0.05),不同组合草颗粒发酵液pH值变化趋势相同,24h内pH值都保持在6.36～6.57之间,适宜微生物发酵;(2)对比总挥发性脂肪酸(VFA)和乙酸/丙酸比值发现,各组合间浓度变化显著,但同一组合VFA在不同时段的变化趋于平缓,有利于绵羊营养吸收;(3)经24h体外培养产气试验表明,苜蓿与玉米秸秆混合制粒后,能显著提高产气量和瘤胃内DM和NDF的降解率,且正组合效应显著,各组合总的可降解部分和快速降解部分显著提高(P< 0.05),慢速降解部分显著降低(P< 0.05);(4)玉米秸秆:苜蓿25:5正组合效应最高.%The nutrition value of mixed grass pellet of alfalfa and corn stalk was studied with the experiments of digestion in vitro.The results showed that: (1) The ratio of alfalfa to corn in mixed grass pellet had much effect on pH value of ferment solution(P＜0.05),and had same trend in grass pellet of different combination, the pH value all kept 6.36～6.57 in 24 hours, which was suitable to microbial fermentation; (2)Through comparing the acetic acid/propyle acid and VFA, it was found that concentration changed significantly, and VFA became gentle in different time interval in a same combination, which was beneficial to ruminant nutrient uptaking; (3)Through the experiment of in vitro gas production for 24 hours, the results showed that the mixed grass pellet of alfalfa and corn stalk could improve gas production and degradation rate of DM and NDF in the rumen, and the positive combination effects was significant.The total degeneration part and fast degeneration part were improved significantly (P＜ 0.05), slow degeneration part was reduced significantly (P＜0.05); (4) The optimal ratio of corn stalk to alfalfa was 25:75.