发酵天数对裹包全混合日粮发酵品质及有氧稳定性的影响

Effect of Fermentation Days on Fermentation Quality and Aerobic Stability of Whole Coated Diet

本试验旨在研究运用裹包发酵技术对全混合日粮(TMR)进行裹包发酵,确定适宜发酵天数,为裹包发酵全混合日粮(FTMR)在牧场中应用提供理论依据。试验以新鲜TMR为原料裹包发酵,于发酵0、3、7、15、30 d取样,分别设为D0、D3、D7、D15、D30共5个处理组,每组8个重复,测定其发酵品质、营养成分及微生物变化;同时将FTMR暴露到空气中,用多通道温度记录仪记录温度变化,并在1、3、5 d后取样分析,评定其有氧稳定性。结果表明:发酵7 d后乳酸含量为3.31%~3.52%DM(干物质基础),pH为4.43~4.39,氨态氮(NH_3-N)占总氮(TN)比例为2.58%~3.33%,丙酸在D7和D30处理组检出且小于0.2%DM,说明FTMR在D7、D15和D30发酵品质良好;有氧暴露期间,D0和D3组在暴露5 d后霉菌和酵母菌数大于5 log10CFU/g,样品温度高于环境温度2℃,说明已发生腐败;而D7、D15和D30组未出现上述状况,说明具有较高的有氧稳定性。综上表明,FTMR在发酵7 d后表现出良好的发酵品质,并具有较高的有氧稳定性。

The purpose of this experiment is to study the use of wrapping fermentation technology to package the total mixed ration（TMR） for fermentation, to determine the appropriate number of fermentation days, and to provide a theoretical basis for the application of wrapping fermentation TMR（FTMR） in pasture. The fresh TMR was packaged and fermented. The samples were collected after 0, 3, 7, 15 and 30 d, and were divided into five treatment groups： D0, D3, D7, D15 and D30, with 8 replicates each. The fermentation quality, nutrient composition and microbial changes were determined; At the same time, FTMR was exposed to air. The temperature changes were recorded with a multi-channel temperature recorder, and the aerobic stability was assessed by sampling at 1, 3 and 5 d after aerobic exposure. The results showed that the content of lactic acid was 3.31%~3.52% DM, pH value was 4.43~4.39 and the content of ammonia nitrogen（NH_3-N） was 2.58%~3.33% of total nitrogen（TN） after 7 days fermentation. Propionic acid was only detected in D7 and D30 treatment group and less than 0.2% DM. These findings showed that fermentation quality of FTMR was good after 7, 15 and 30 days of fermentation, and no corruption and deterioration. During the aerobic exposure period, the number of molds and yeasts in D0 and D3 groups was more than 5 log10 CFU/g after 5 days exposure, and the temperature of the samples was higher than the ambient temperature of 2Ⅳ, indicating that corruption had occurred. The D7, D15 and D30 groups did not show the above situation, indicating a high aerobic stability. The results showed that FTMR showed good fermentation quality after 7 days of fermentation and had high aerobic stability.