乳酸菌对低温下玉米秸秆黄贮发酵品质及有氧稳定性的影响

Effects of Lactic acid bacteria on fermentation quality and aerobic stability of corn stover silage ensiled at low temperature

为研究低温下乳酸菌对玉米秸秆黄贮发酵品质及有氧稳定性的影响,试验采用小规模发酵法,以收获籽粒后的玉米秸秆作为原料,分别添加乳酸菌LAB_1(Lactobacillus plantarum)、LAB_2(Lactococcus lactis)、LAB_3(Lactobacillus paracasei)、LAB_1+LAB_2、LAB_1+LAB_3、LAB_2+LAB_3,在低温(4℃)条件下发酵30 d后开封,测定发酵参数、微生物数量及有氧稳定性。结果表明:与对照组相比,添加乳酸菌可以降低pH和NH3-N含量(P <0.05),提高乳酸含量(P <0.05),抑制大肠杆菌、丁酸菌、霉菌等有害微生物的生长;在乳酸菌添加的各组间,pH从低到高依次为:LAB_3组<LAB_2+LAB_3组<LAB_2组<LAB_1组<LAB_1+LAB_2组<LAB_1+LAB_3组,但各组间无显著差异(P> 0.05),LAB_3组的乳酸含量较LAB_1、LAB_2、LAB_1+LAB_2、LAB_1+LAB_3、LAB_2+LAB_3组分别提高了11.85%、7.09%、3.42%、13.53%、4.86%,但无显著差异(P> 0.05),LAB_3组的氨态氮含量显著低于LAB_1组(P <0.05)。大肠杆菌数量从低到高依次是:LAB_3组<LAB_1+LAB_3组<LAB_1+LAB_2组<LAB_2组<LAB_1组<LAB_2+LAB_3组;发生有氧氧化后,乳酸菌添加组的NH3-N含量、丁酸菌、霉菌以及酵母菌数量均显著低于对照组(P <0.05)。由此可见,乳酸菌能提升低温条件下玉米秸秆黄贮的发酵品质,提高发酵饲料的有氧稳定性,其中添加乳酸菌LAB_3效果最好。

This experiment was conducted to study the effects of Lactic acid bacteria on the fermentation quality and aerobic stability of corn stover silage ensiled at low temperature by means of the small-scale fermentation method.The corn straw was used as raw material,and LAB1 (Lactobacillus plantarum),LAB2 (Lactococcus lactis),LAB3 (Lactobacillus paracasei),LAB1+LAB2,LAB1+LAB3 and LAB2+LAB3 were added respectively.Treatments were imposed at ensiling under low temperature (4 ℃).When open the bags,the fermentation parameters,microbial composition and aerobic stability were determined.The results showed that compared with the control silage,the silage with Lactic acid bacteria inoculant could decrease the pH and NH3-N content (P < 0.05),increase the lactic acid content (P < 0.05),and inhibit the growth of harmful microorganisms such as coliform bacteria,clostridium,molds.Among the silage with Lactic acid bacteria inoculant,the pH from lowest to highest was:LAB3 group<LAB2+LAB3 group<LAB2 group<LAB1 group<LAB1+LAB2 group<LAB1+LAB3 group,but there was no significant difference (P > 0.05).The lactic acid content in silage with LAB3 were higher than those of LAB1,LAB2,LAB1+LAB2,LAB1+LAB3,LAB2+LAB3 groups(11.85%,7.09%,3.42%,13.53% and 4.86%,respectively),but there was no significant difference (P > 0.05).The Ammonia-N content in silage LAB3 was lower than that in silage with LAB1 (P < 0.05).The number of coliform bacteria from lowest to highest was:LAB3 group<LAB1+LAB3 group<LAB1+LAB2 group<LAB2 group< LAB1 group<LAB2+LAB3 group.After the silage aerobic oxidation,the content of NH3-N and the numbers of clostridium,molds and yeasts in control silage were higher than in LAB inoculant additive silage.In conclusion that the Lactic acid bacteria could improve the fermentation quality and aerobic stability of the corn stover ensiled at low temperature.In addition,the use of LAB3 as the silage inoculant was preferable.