笋壳替代全株玉米TMR发酵品质及有氧稳定性研究

本试验旨在探讨不同比例笋壳逐步替代全株玉米对全混合日粮(total mixed ration,TMR)发酵品质、营养价值和有氧稳定性的影响,确定适宜的笋壳替代水平。试验设对照组、15%笋壳组、25%笋壳组和35%笋壳组。青贮后第5, 7, 14, 30, 90天开窖取样,测定其发酵品质、营养成分及微生物变化;同时将青贮90 d的发酵TMR暴露到空气中,用多通道温度记录仪记录温度变化,并分别在有氧暴露第3, 6, 9和14天取样分析,评定其有氧稳定性。结果表明,尽管在整个青贮过程中随着笋壳替代比例的增加,各组乳酸含量逐渐降低,pH显著(P<0.05)升高,氨态氮/总氮逐渐上升,但青贮90 d后15%和25%组具有较高的乳酸含量(60.16~64.94 g/kg DM)、较低的pH(4.15~4.20)、氨态氮/总氮(55.56~58.73 g/kg TN)和极少量的丁酸含量(1.05~1.47 g/kg DM),仍显示良好的发酵品质。有氧暴露期间,对照组在有氧暴露第9天pH开始急剧上升,乳酸、乙酸和水溶性碳水化合物含量大幅度下降,发生有氧腐败,而笋壳处理组在有氧暴露14 d内pH缓慢上升,乳酸、乙酸和水溶性碳水化合物含量逐步降低,且温度也未超过环境温度2℃,与对照组相比有氧稳定性明显提高。其中15%组和25%组不仅有良好的发酵品质而且有氧稳定性高。从对笋壳资源的最大化利用角度出发,用25%的笋壳替代TMR中的全株玉米最为适宜。

Fermentation quality,nutritional values and aerobic stability of the total mixed ra-tion after replacing whole-plant corn with different proportions of bamboo shoot shell

The objective of this experiment was to evaluate the effects of replacing whole-plant corn with differ-ent proportions of bamboo shoot shell (BSS)on the fermentation quality,nutritional value and aerobic stability of total mixed ration (TMR)silage.There were four treatments:0% BSS (control),15% BSS (15%),25%BSS (25%),35% BSS (35%).The silos were opened at 5,7,14,30 and 90 days after ensiling in order to de-termine the fermentation quality,nutritional and microbial compositions of the silages.Meanwhile,we esti-mated the aerobic stability of the silages in conjunction with recording of temperature variations using an online multi-channel data logger,and analyzed the chemical composition of samples taken at day 3,6,9 and 14 of aer-obic exposure.As the proportion of BSS increased,the lactic acid contents decreased gradually,the pH in-creased significantly (P <0.05)and the ammonia/total nitrogen ratios increased gradually during the ensiling. The 15% and 25% treatments still retained a good fermentation quality as indicated by high lactic acid contents (60.16-64.94 g/kg dry matter),low pH (4.15-4.20)values,low ammonia/total nitrogen ratios (55.56 -58.73 g/kg total nitrogen)and minor butyric acid contents (1.05 -1.47 g/kg dry matter).During the period of aerobic exposure,the initiation of aerobic deterioration of the control silage had occurred by day 9,as indica-ted by a dramatic rise in the pH and a decline in the lactic acid,acetic acid and water soluble carbohydrate con-tent,and the temperature increased more than 2℃ above the environment temperature after 195 h of exposure to air.However,for the BSS treatments,the increase in pH and the decline of lactic acid,acetic acid and water soluble carbohydrate contents occurred more slowly than in the control.In addition,the temperature of the si-lages containing BSS increased no more than 2℃ above the environment temperature within the 14 days of aero-bic exposure,which indicated that the BSS treatment significantly improved the aerobic stability compared to the control,but may have decreased the feeding value.Overall,the 15% and 25% treatments showed not only better fermentation quality but also higher aerobic stability compared to other BSS treatments.From the per-spective of maximizing the use of BSS resources,it is suggested that the most appropriate replacement level of BSS is 25% in whole-plant corn TMR silage.