In vitro investigation of the effect of dairy propionibacteria on rumen pH,lactic acid and volatile fatty acids  

作　　者：Jianbiao Luo Chaminda Senaka Ranadheera Stuart King Craig Evans Surinder Baines 

机构地区：[1]School of Environmental&Life Sciences,The University of Newcastle,Callaghan NSW 2308,Australia [2]Advanced Food Systems Research Unit,College of Health and Biomedicine,Victoria University,Melbourne VIC 3030,Australia [3]School of Health Sciences,The University of Newcastle,Callaghan NSW 2308,Australia

出　　处：《Journal of Integrative Agriculture》2017年第7期1566-1575,共10页农业科学学报（英文版）

基　　金：The University of Newcastle,Australia for financial support

摘　　要：Ruminal acidosis is a prevalent disorder in ruminants such as dairy cows and feedlot beef cattle, caused primarily by the inclusion of a high percentage of readily fermentable concentrates in the diet. The disorder presents as an accumulation of lactic acid, a decrease of pH in the rumen and a subsequent imbalance of the rumen fermentation process with detrimental impacts on the animal＇s health and productivity. Dairy propionibacteria, a group of bacteria characterised by utilization of lactic acid as the favoured carbon source, with propionic acid produced as a by-product, were evaluated in this study as potential direct-fed microbials for use in controlling ruminal acidosis. Acidosis was simulated by introduction of high concentrations of lactic acid into rumen fluid samples and a multi-strain in vitro analysis was conducted, whereby changes in pH and lactic acid metabolism were compared in identical acidified rumen samples, following inoculation with various propionibacteria. This was followed by a study to evaluate the effect of bacterial inoculation dosage on acid metabolism. The results indicated that lactic acid levels in the rumen fluid were significantly reduced, and propionic acid and acetic acid concentrations both significantly increased, following addition of propionibacteria. Significant ＇between strains＇ differences were observed, with Propionibacterium acidopropionici 341, Propionibacterium freudenreichfi CSCC 2207, Propionibacterium jensenfi NCFB 572 and P. jensenii 702 each producing more rapid reduction of lactic acid concentration than P. freudenreich# CSCC 2206, P. acidopropionici ATCC 25562 and Propionibacterium thoenii ATCC 4874. Furthermore, the efficacy of this application was dosage related, with the rates of reduction in lactic acid levels and production of propionic acid, both significantly greater for the higher （10^10 cfu mL-1） compared with lower （10^5 cfu mL-1） dosage inoculation. The results confirmed that the introduction of propionibacteria could promote more rapidRuminal acidosis is a prevalent disorder in ruminants such as dairy cows and feedlot beef cattle, caused primarily by the inclusion of a high percentage of readily fermentable concentrates in the diet. The disorder presents as an accumulation of lactic acid, a decrease of pH in the rumen and a subsequent imbalance of the rumen fermentation process with detrimental impacts on the animal＇s health and productivity. Dairy propionibacteria, a group of bacteria characterised by utilization of lactic acid as the favoured carbon source, with propionic acid produced as a by-product, were evaluated in this study as potential direct-fed microbials for use in controlling ruminal acidosis. Acidosis was simulated by introduction of high concentrations of lactic acid into rumen fluid samples and a multi-strain in vitro analysis was conducted, whereby changes in pH and lactic acid metabolism were compared in identical acidified rumen samples, following inoculation with various propionibacteria. This was followed by a study to evaluate the effect of bacterial inoculation dosage on acid metabolism. The results indicated that lactic acid levels in the rumen fluid were significantly reduced, and propionic acid and acetic acid concentrations both significantly increased, following addition of propionibacteria. Significant ＇between strains＇ differences were observed, with Propionibacterium acidopropionici 341, Propionibacterium freudenreichfi CSCC 2207, Propionibacterium jensenfi NCFB 572 and P. jensenii 702 each producing more rapid reduction of lactic acid concentration than P. freudenreich# CSCC 2206, P. acidopropionici ATCC 25562 and Propionibacterium thoenii ATCC 4874. Furthermore, the efficacy of this application was dosage related, with the rates of reduction in lactic acid levels and production of propionic acid, both significantly greater for the higher （10^10 cfu mL-1） compared with lower （10^5 cfu mL-1） dosage inoculation. The results confirmed that the introduction of propionibacteria could promote more rapid

关 键 词：PROBIOTICS ruminal acidosis lactic acid propionic acid dairy Propionibacterium 

分 类 号：S816[农业科学—饲料科学]