石粉对全混合日粮发酵品质和微生物种群的影响

Effect of Limestone on Fermentation Quality and Microbial Populations of Total Mixed Ration

为探究石粉对高温条件下全混合日粮(total mixed ration,TMR)过度发酵的抑制效果,试验设置不添加石粉的对照组(L0组)以及添加0.5%(L1组)、1.0%(L2组)和1.5%(L3组)的试验组,在35℃条件下发酵7、21、35、56 d和90 d后开封,测定发酵品质、化学组分和微生物数量。结果显示:石粉能显著提高发酵TMR的pH、乳酸和氨态氮(NH3-N)含量以及乳酸菌数量(P<0.05),降低干物质(dry matter,DM)含量和中性洗涤纤维(neutral ditergent fiber,NDF)含量(P<0.05)。发酵90 d后,L0、L1组和L2组的NH3-N含量占总氮含量的5%以下,与L0组相比,L1组和L2组有更高的乳酸含量(P<0.05)。因此,生产上推荐添加石粉的量以不超过1.0%为宜。

To investigate the inhibitory effect of limestone on over-fermentation of total mixed ration(TMR)under high temperature,TMR was ensiled with limestone at levels of 0(L0 group),0.5%(L1 group),1.0%(L2 group) and 1.5%(L3 group).Fermentation quality,chemical compositions and microbial counts were assessed after 7,21,35,56 days and 90 days of ensiling.The result showed that limestone addition could increase the contents of lactic acid and ammonia nitrogen(NH3-N),the count of lactic acid bacteria and the pH value of TMR(P<0.05),while decrease the contents of dry matter(DM) and neutral detergent fiber(NDF)(P<0.05).After 90 days of ensiling,ammonia-nitrogen content in L0,L1 group and L2group was less than 5%,L1 and L2 groups contained higher lactic acid content than L0 group(P<0.05).Therefore,the ratio of 1.0% limestone was recommended in practice.