植物乳酸菌和贮藏温度对辣木叶青贮品质的影响

Effect of lactic acid bacteria and storage temperature on the quality of Moringa oleifera leaf silage

从辣木叶青贮中筛选分离出4个乳酸菌菌株,鉴定后分别为Lactobacillus plantarum(LP),Lactobacillus far⁃ciminis(LF),Weissella thailandensis(W)和Lactococcus lactis(E)。试验旨在探究不同温度下添加植物乳酸菌对辣木叶青贮的青贮品质、营养成分和单宁含量的影响。采用双因素(温度×植物乳酸菌)完全随机设计,两个温度组为15和30℃,乳酸菌处理组为CK,LP,LF,W和E。在青贮第60天时开袋取样进行测定。结果表明,辣木叶原料粗蛋白质含量为25.31%,可溶性碳水化合物含量为7.53%,添加乳酸菌可以显著降低pH,增加乳酸和乙酸含量,同时使乳酸菌数量和氨态氮含量显著降低(P<0.05)。贮藏温度在15℃时,乳酸菌数量,真蛋白含量显著高于30℃(P<0.05)。同时,非蛋白氮、氨态氮和游离氨基酸含量在15℃的贮藏温度时都显著低于30℃(P<0.05)。青贮后,各处理组的单宁含量都有下降,但无显著差异(P>0.05)。辣木叶蛋白质丰富,易于调制青贮饲料,较低的贮藏温度和添加植物乳酸菌对辣木叶青贮品质有明显的改善作用,但对降解单宁含量并未产生显著影响。

Four lactic acid bacterial strains,isolated and selected from Moringa oleifera leaf(MOL)silage,were identified as Lactobacillus plantarum(LP),Lactobacillus farciminis(LF),Weissella thailandensis(W),and Lactococcus lactis(E),respectively.Fermentation quality,nutrient contents and tannin contents of MOL ensiled without or with the four strains at 15 and 30℃external temperature were investigated in the present study.A completely randomized two-factor(lactic acid bacterium×temperature)design was employed.After 60 days the silages were opened to determine and analysis.It was found that the contents of crude protein and water-soluble carbohydrates were 25.31%and 7.53%,respectively,on a dry matter basis.Adding lactic acid bacteria decreased pH,lactic acid bacteria number and ammonium nitrogen content(P<0.05),while increasing the lactic acid and acetic acid contents(P<0.05).Silage fermented at 15℃showed higher lactic acid bacteria number and true protein content than when fermented at 30℃(P<0.05).Furthermore,silage fermented at 15℃external temperature had lower contents of non-protein nitrogen,ammonium nitrogen and free amino acid than silage fermented at 30℃external temperature(P<0.05).Tannin contents in each treatment group decreased after ensiling without significant difference between treatments(P>0.05).In conclusion,MOL contain high protein content and they are easy to ensile.Lactic acid bacteria inoculants and a relatively low fermentation temperature are effective to improve the quality of MOL silage.