【作者】 张想峰；

【导师】 艾尼瓦尔·艾山；

【作者基本信息】 新疆农业大学 ， 动物营养与饲料科学， 2009， 硕士

【摘要】 新疆小芦苇分布广泛,是反刍动物良好的饲草资源之一。本研究从自制的新疆小芦苇青贮中分离出乳酸菌进行鉴定,对鉴定出的菌株进行产酸试验,筛选出优势菌株,添加到原料中进行青贮,同时做甲酸和商品青贮添加剂的对比试验,确定出调制新疆小芦苇青贮的最佳乳酸菌添加剂。试验一:本试验共分离得到了15株乳酸菌,根据《伯杰氏细菌鉴定手册》第八版、《常见细菌系统鉴定手册》中的种属表述和生化鉴定结果,经鉴定2株(Hz2-1 Hz2-2)为戊糖乳杆菌(L. pentosus),2株(Hz3-1 Hz3-2)为植物乳杆菌(L. plantarum),2株(Zar2-8 Zar2-9)为牛粪乳杆菌(L. dung),2株(Zar8-3 Zar8-4)为短乳杆菌(L. brevis),3株(Gsr1-1 Hz1-1 Zar9-4)为德氏乳杆菌保加利亚亚种(L. delbrueckii subsp .bulgaricus),2株为片球菌(Pediococcus),2株为乳球菌(Lactococcus)。试验二:从不同菌株发酵产酸试验的结果来看,发现Hz2-1、Hz3-1、Gsr-t具有较强的产酸能力,其中Hz3-1的pH最低可达3.50,是新疆小芦苇青贮发酵过程中的主要产酸菌株。对其生长曲线进行测定,发现杆菌Hz2-1、Hz3-1的生长周期较长,在18h后达到稳定期,球菌Gsr-t的生长周期较短,但前期产酸速率较快。试验三:将筛选出的Hz2-1 (L. pentosus)、Hz3-1 (L. plantarum)、Gsr-t(Pediococcus),添加到新疆小芦苇中进行青贮。结果表明:添加乳酸菌均可以改善青贮的发酵品质,其中以植物乳杆菌+ Gsr-t发酵品质最好,pH最低可达3.50。与对照组相比乳酸(LA)含量增加了44%、丁酸(BA)含量降低了71%,差异极显著(P<0.01)。NH3-N含量降低了41%,差异极显著(P<0.01)。甲酸和商品青贮添加剂显著降低了NH3-N含量,它们之间差异不显著(P>0.05)。通过对新疆小芦苇青贮营养成分的影响结果可以看出,与对照组相比,乳酸菌处理对ADF和EE影响不明显,其中植物乳杆菌+ Gsr-t处理降低了DM和OM含量,差异显著(P<0.05),同时,也降低了CP、NDF含量,提高了ADF含量,但差异均不显著(P>0.05)。戊糖乳杆菌+ Gsr-t处理提高了CP含量,但差异不显著(P>0.05),其它成分与植物乳杆菌+ Gsr-t效果相似。单一菌株、甲酸和商品青贮添加剂效果不如植物乳杆菌+ Gsr-t和戊糖乳杆菌+Gsr-t。因此,通过自选乳酸菌对新疆小芦苇发酵品质和营养成分的影响,我们可以看出单一菌株、甲酸和商品青贮添加剂对新疆小芦苇发酵品质有一定的改善,总体效果不如植物乳杆菌+ Gsr-t和戊糖乳杆菌+ Gsr-t处理,其中植物乳杆菌+ Gsr-t效果更佳,适合做新疆小芦苇青贮的发酵促进剂。更多还原

【Abstract】 Xinjiang small reed is widely distributed in Xinjiang and it is one of best forage resources for ruminants.LAB was isolated from manmade Xinjiang small reed silage in this study and we have had cidogenic test for identified strains.Dominant strains were selected and added to the raw materials for silage. At the same time,contrast test with formic acid and commodity silage additive were carried out and the best addition of LAB for Xinjiang small reed silage was determinated.TestⅠ: 15 strains LAB were isolated from Xinjiang small silage.According to the results of species formulation and biochemical identification in "Bergey’s Manual Determinative Bacteriology" (Eighth Edition),two strains were Lactobacillus pentosus (Hz2-1 Hz2-2),two were Lactobacillus plantarum (Hz3-1 Hz3-2),two were lactobacillus dung (Zar2-8 Zar2-9),two were Lactobacillus brevis(Zar8-3, Zar8-4),three were Lactobacillus delbrueckii subsp .bulgaricus (Gsr1-1 Hz1-1 Zar9-4),two were Pediococcus and two were Lactococcus.Test II: From the results of acidogenic fermentation test with different strains.The Hz2-1,Hz3-1 has a strong ability to produce acid,the pH in Hz3-1 can as low as 3.50 and it was the main strain of produce acid in fermentation of Xinjiang small reed silage.Growth curve of this strain was determinated and found that Hz2-1,Hz3-1 had long growth cycle and achieved stability after 18h.Gsr-t has a short growth cycle while produced acid fast in early period.TestⅢ: The selected strain Hz2-1(L. pentosus),Hz3-1(L. plantarum),Gsr-t (Pediococcus) were added to Xinjiang small reed for making silage,results show that addition of LAB could improve the fermentation quality of silage,in which Lactobacillus plantarum+Gsr-t had the best fermentation quality.It’s pH can up to 3.50.The content of lactic acid was increased by 44% and butyric acid was decreased by 71% compared with the control group,the difference was significant(P<0.01).The content of NH3-N was decreased by 41% and the difference was significant(P<0.01).Formic acid and commodity silage additive had significantly decreased the content of NH3-N,the differences between them was not significant(P> 0.05).Though the results of nutrient composition in Xinjiang small reed silage,we can found that LAB has no significant effect on ADF and EE compare with the control,and the content of ADF and CP were decreased when treated with Lactobacillus plantarum+Gsr-t, the difference was significant (P<0.01), while the content of CP and NDF were decreased and ADF were increased,the difference was nit significant(P> 0.05).Other components had the same effect with Lactobacillus plantarum+Gsr-t.The impact of single strain,formic acid and commody silage additive were not equal to Lactobacillus plantarum+Gsr-t and Lactobacillus pentosus+Gsr-t.Therefore,through the effect of fermentation quality and nutrition content with LAB in Xinjiang small reed silage.We can found that single strain,formic acid and commody silage additive could somewhat improve the fermentation quality of Xinjiang small reed,but the overall effect was not better than Lactobacillus plantarum+Gsr-t and Lactobacillus pentosus+Gsr-t,in which Lactobacillus plantarum+Gsr-t had the best effectiveness and was suitable for fermentation accelerate of Xinjiang small reed silage.更多还原