| Tibet animal husbandry has a long unique history and rich resources.But the special cold plateau climate limits the development of animal husbandry.Tibet’s dry season and rainy season has statistically significant differences,from south to northwest gradually reduce rainfall,drought degree aggravating gradually,the supply of pastoral areas forage grass resources created serious shortage phenomenon.In addition,under the concept of bondage of traditional natural economy,the seasons change and change of the nomadic mode still exists in most of the pastoral areas of Tibet,forage grass shortage and pasture degradation has become the main factors that hinder the local economic and social development with the expansion of the scale of animal husbandry.In order to meet the requirements of the parish ruminant livestock for hours,the agriculture surplus to create high quality silage grass and crops are one of the effective ways to solve the pastoral animal husbandry development plight.This research use lactic acid bacteria sieved out of from Tibet silage,namely Pediococcus acidilactici and Pediococcus pentosaceus,as additive added to the grass and legume forage grass silage,then analyzes its fermentation quality,screening for good lactic acid bacteria additives of silage and the influence of lactic acid bacteria additives on different raw materials for silage.This will provide data support for the practice and application of silage additives in lactic acid bacteria,further to the Qinghai-Tibet plateau with lactic acid bacteria silage additives provides theory basis for the development and application.1.Study on phenotypic,physiological and biochemical characteristics,Acid-production and growth rate of Pediococcus acidilactici and Pediococcus pentosaceusAfter physiological and biochemical characteristics research,17 lactic acid bacteria strains are homo-fermentation and gram positive,produce gas peace-making glucose were negative,Acid-production and growth rate of LAB is high,the change of Acid-production and growth rate of three Pediococcus acidilactici is more significant,as well as part of pediococcus pentosaceus strains.In further research,the effect on the quality improvement of the local pasture fermentation has a certain guiding role.2.Study on the effect of Pediococcus acidilactici on silage fermentation quality of grasses in Tibet.Choose 3 strains of lactic acid bacteria strains selected from laboratory as the additive works on four kinds of forage grass silage for test,all silos were opened after 60 days of ensiling,and then determined the fermentation quality.In alfalfa silage:the experiment was performed with four treatments:(1)no additives(C),(2)LTG7,(3)LH9,(4)LOG9.Dry matter content of LTG7 lactic acid treatment group was 84.04 g/kg DM,which was significantly higher than control group C(P<0.05)and LH9,LOG9 treatment group,total volatile fatty acids in all treatment groups were lower than that in the control C,LTG7 treatment group total volatile fatty acids was significantly lower than the control group C(P<0.05).The number of aerobic bacteria and yeast of the control group C was significantly higher than LTG7 group(P<0.05).Adding LTG7 improved the fermentation quality of alfalfa silage in Tibet.In common vetch silage:the experiment was performed with four treatments:(1)no additives(C),(2)LTG7,(3)LH9,(4)LOG9.The amounts of total volatile fatty acid,AN/TN ratios,yeast counts of LH9 and LTG7 group was significantly lower than the control group C(P<0.05),the water soluble carbohydrate content and lactic acid bacteria counts were higher,improved the fermentation quality of common vetch silage.In oat silage:the experiment was performed with four treatments:(1)no additives(C),(2)LTG7,(3)LH9,(4)LOG9.Compared with the control group C after adding lactic acid bacteria,LOG9 group significantly decreased AN/TN ratio,total volatile fatty acid,butyric acid,propionic acid contents(P<0.05)of oat silage,and water soluble carbohydrate content is high,LOG9 treatment showed the best effect on improving fermentation quality of oat silage.In common Green wheat silage:the experiment was performed with four treatments:(1)no additives(C),(2)LTG7,(3)LH9,(4)LOG9.After adding lactic acid bacteria for 60 days,compared with the control group C,LTG7 group had higher amount of DM,water soluble carbohydrate content and lactic acid bacteria counts,lower content of total volatile fatty acid and AN/TN ratio,significantly improved the fermentation quality of common Green wheat silage.3.Study on the effect of Pediococcus pentosaceus on silage fermentation quality of grasses in Tibet.In Alfalfa silage,LL8,TG20,LG4,CG35,AG11,T22 lactic acid bacteria treatments shows lower pH,higher lactic acid content,low WSC,less number of aerobic bacteria,yeast and fermentation quality is relatively good.AN/TN of T22 lactic acid bacteria group is 118.72 g/kg TN,which is the most close to the quality standard of good silage,compared with other treatment and control group.Adding pediococcus pentosaceus T22 strains could significantly improve the lactic acid content of alfalfa silage(P<0.05).Lower the pH value,AN/TN ratio and the number of anaerobic-aerobic bacteria,showed the most obvious improvement of alfalfa silage fermentation quality.In common vetch silage,compared with control group,L08,T22,TG20 lactic acid bacteria treatment groups had low pH value,high lactic acid and WSC contents,and VFA contents and AN/TN ratios were low,yeast counts were relatively low,which could significantly improve the common vetch silage fermentation quality and satisfy the requirements of the silage technology in Tibet.In oats silage,after adding pediococcus pentosaceus for 60 days,the DM of all lactic acid bacteria treatments is generally decline,WSC content on the high side,yeast and anaerobic-aerobic bacteria increased,these treatments can not achieve the desired effect.But compared with the control group C,lactic acid,the ratio of lactic acid and acetic acid is high,AN/TN decreased significantly.In addition,compared with the control,LH7,L08,AG11,LW7 treatment group with low pH value,WSC,VFA,AN/TN content,high content of lactic acid,LA/AA,these treatment groups have a good effect on improving the fermentation quality of oats silage in Tibet.In green wheat silage results,lactic acid content,LA/AA ratio,dry matter content of all groups were high,most of propionic acid and butyrate contents were at a level that cannot be detected,AN/TN ratio was lower than the control group,yeast and anaerobic-aerobic bacteria counts showed no significant difference among all groups(P>0.05).Analysis by synthesis,lactic acid contents and LA/AA ratios of LL8,L07,M35 and AG11 treatment groups were high,WSC,AN/TN,yeast and aerobic bacteria counts were low,which could significantly improve the green wheat silage fermentation quality in Tibet. |
