Using dietary propionic acid to limit Salmonella gallinarum colonization in broiler chicks

This experiment was conducted to study the effect of dietary propionic acid on inhibitory effect of Salmonella gallinarum. Day-old 144 broiler chicks were randomly distributed into four dietary treatments, three replicates per treatment. The four dietary treatments consisted of 0.0, 0.6, 1.2, and 1.8% dietary propionic acid. Chicks were challenged orally on three days of age with 10(6) cfu Salmonella gallinarum. Sample of crop and cecal contents were obtained on Days 1, 8 and 15 post-inoculation. The pH of crop contents decreased significantly (p <0.01) for groups of chicks provided 1.2 and 1.8% propionic acid in the diet as compared with those provided 0.6% propionic acid and control group. The pH of cecal contents decreased significantly (p <0.01) for groups of chicks provided with 0.6, 1.2 and 1.8% of propionic acid as compared with control group. The number of Salmonella gallinarum positive culture in the crop and ceca of chicks, decreased significantly (p <0.01) from the groups provided with 0.6, 1.2 and 1.8% of propionic acid in the diet at day 1, 8 and 15 post-inoculation. The addition of 1.8% propionic acid in the diet provided a high level of protection against colonization than did 0.6 and 1.2%. These results indicate that the addition of propionic acid in a concentration of 1.2 or more to the diet of newly hatched chicks significantly decreases crop and cecal colonization by Salmonella gallinarum.