Screening And Characterization Of Lactic Acid Bacteria From The Rumen Fluid Of Hainan Black Goat

The purpose of this experiment was to screen and identify lactic acid bacteria from the rumen fluid of Hainan black goat and also to provide high quality lactic acid bacteria for the black goat feed silage.Fifteen Gram-positive,catalase-negative strains were isolated from the rumen fluid of Hainan black goat in this experiment.These strains were identified and characterized elementarily by morphological,physiological and biochemical tests.After that we had tested the tolerance ability of three strains in different pH,temperature and salt concentration.All strains were divided into three groups according to the tested result,and then select one representative strain from each group.Based on 16S rDNA gene sequence analysis,HBG11,HBG46 and HBG86 were identified as Enterococcus durans,Lactobacillus plantarum,Lactobacillus casei respectivly.The result showed that HBG46 had the advantage to other two strains in lactic acid production and growth rate,and it reached its final pH at 3.61.It also showed that HBG86 grew better than the other two strains when the temperature was setted at 10? and 45 ?.Besides,these three strains showed the same but weak growth condition at a high temperature(55?),low pH(pH=2.5)and the same salt concentration.One lactic acid bacteria was chosen for silage fermentation which had a high rate of growing and acid production ability.In this experiment,we setted seven treatments:no additive(?),0.1%HBG46(?),cellulase(?),gastric fluid(?),0.1%HBGX1(?),0.1%HBG46 and 0.1%HBGX1(?),0.1%HBG46 and cellulase(?).The result showed that group ? had the worst silage quality while group ? which produce acid rapidlly had the best silage quality.Silage that added lactic acid bacterial and cellulase present a better result in pH and aerobic bacteria controlling than those without adding lactic acid bacterial and cellulase.