|Nisbet, David - Dave|
Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/21/2009
Publication Date: 8/5/2009
Publication URL: http://handle.nal.usda.gov/10113/57249
Citation: Dunkley, K.D., Callaway, T.R., O'Bryan, C., Kundinger, M.M., Dunkley, C.S., Anderson, R.C., Nisbet, D.J., Crandall, P.G., Ricke, S.C. 2009. Cell yields and fermentation responses of a Salmonella Typhimurium poultry isolate at different dilution rates in an anaerobic steady state continuous culture. Antonie Van Leeuwenhoek. 96:537-544. Interpretive Summary: Salmonella are pathogenic bacteria that can cause human foodborne infections. These bacteria are able to survive in various environments, including the gastrointestinal tract of food animals. In order to learn more about how Salmonella survive and cause infections, we conducted studies using a special model that simulates the growth conditions that Salmonella may experience when in the gut of food animals. We found that cell protein concentrations were higher when the model simulated moderate rather than slow or fast rates of gut emptying. Additionally, we found that the Salmonella cells were unable to utilize as much glucose when grown under conditions simulating rapid gut emptying than when grown under moderate or slow rates of gut emptying. These results indicate that Salmonella bacteria grew less efficiently at rapid rates of gut emptying and may partially explain the host diarrhea response during infection. Ultimately, these results may help livestock producers and processors develop feeding strategies that reduce the chance of carcass contamination during processing, thereby producing safer meat and poultry products for the American consumer.
Technical Abstract: The objectives of these studies were to determine cell yield and fermentation responses of a Salmonella enterica serovar Typhimurium poultry isolate using various dilution rates in steady state continuous culture incubations. S. enterica Typhimurium cells were propagated in continuous cultures with a total volume of 0.50 l of Luria Bertani medium containing 0.1% glucose. Dilution rates from 0.0125 to 1.44/h were used. Cell protein concentration generally increased linearly with increased dilution rate up to a rate of 0.54/h and declined at the higher dilution rates. Glucose consumption gave a similar pattern to cell protein concentration by declining at the three highest dilution rates. Short chain fatty acid production was inconsistently influenced by dilution rate. Acetate, the most predominant fatty acid produced, declined at the higher dilution rates, as did propionate. Ammonia production remained stable at the lowest dilution rates, but increased significantly at a dilution rates above 0.27/h.