Effect of Dietary Formic Acid Level on Artificially Contaminated Broiler Feed with Salmonella Gallinarum

Reported here are the effects of additive formic acid on inhibitory effect of Salmonella gallinarum in poultry feed. Two experiments were conducted to investigate the viability of S. g. and pH of poultry feed using different dietary formic acid level (0.0, 0.5, 1.0 and 1.5%) on inhibitory effect of S. g. in broiler feed. Experiment one was conducted to investigate the viability of S. g. and pH of artificially contaminated diet at 0, 1, 3, 5 and 7 days after treatment in vitro. Formic acid showed a significant (P 0.05) reduction in the viability for all treatments with time after treatment. Various formic acid levels in vitro showed a reduction in the pH of the diet depend upon the concentration of treated acid and the diet remains acidic below the growth range of S. g,. which means that the bacterial cells were exposed to stressful conditions that make them unable to grow. Experiment two was conducted to find out the effect of dietary formic acid levels on S. gallinarum colonization and pH in the contents of crop, small intestine, large intestine and ceca and mortality rate of broiler chicks at 7, 14, and 21 days of age when fed artificially contaminated diet with S.g. The numbers of S.g. re-isolated from all treated groups except groups treated with 0.5% formic acid, decreased significantly (p 0.05) compared with the control groups. The treatment significantly (p 0.05) lowered the pH of the crop, small intestine, large intestine, and ceca contents in all groups except the groups treated with 0.5% formic acid compared with the control. The mortality rate of all treated groups showed a significant (p 0.05) reduction in overall mortality rate during (3-21 days) compared with the control. These results indicate that the addition of formic acid in a total concentration of 1.5% to the diet of newly hatched broiler chicks decreases significantly the contamination diet with S.g.