Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/1996
Publication Date: N/A
Technical Abstract: Fermentation acid (volatile fatty acids, VFA) production has been suggested as one possible mechanism by which indigenous cecal bacteria inhibit Salmonella species colonization in the chicken cecum. A continuous flow (CF) culture of cecal bacterial strains from adult broilers has been shown to increase cecal concentrations of propionate and VFA and increase resistance of chicks to Salmonella typhimurium colonization. In this study, we used a Veillonella strain which was isolated from this competitive exclusion CF culture and produces significant amounts of propionate to examine the effect of propionate concentration on its growth. Anaerobically prepared Viande Levure broth (pH 7.0) containing 65.5 mM lactate as the carbon source and various concentrations of propionate were inoculated with the Veillonella strain. Batch culture growth rate was determined by linear regression as change in absorbance (A600) over time during exponential growth. When all concentrations were compared, growth rates were significantly (P<0.05) decreased from each other at each stepwise increase of propionate (0 mM, 0.91±0.016 h**-1; 20,0.66±0.004; 40, 0.47±0.01; 60, 0.40±0.002; 100, 0.34±0.001; 150, 0.25±0.006; 200,0.25±0.002; 250, 0.17±0.001; and 300, 0.14±0.02) except for the growth rates between 150 and 200 mM. The maximum A600 for the Veillonella strain began to decline at 150-200 mM propionate (A600<1.9) and growth was almost completely inhibited at 300 mM propionate (A600=0.055). This result indicates that this Veillonella strain can still grow, albeit more slowly, at much greater propionate concentrations than typically found in the cecum of birds receiving the CF culture.