Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 1999
Publication Date: N/A
Technical Abstract: Approximately 80% of the U.S. chicken industry uses in ovo Marek's vaccine with an accompanying antibiotic treatment, most often gentamicin. Reports indicate that the use of gentamicin in ovo substantially reduces the effectiveness of some competitive exclusion products. In these studies, the effect of in ovo gentamicin alone, mucosal competitive exclusion (MSCTM) alone, or the combination of in ovo gentamicin followed by MSC on Salmonella colonization of broiler chickens was determined. Three replicate trials were conducted for both the scenario where chicks received Salmonella before MSC treatment and where chicks received Salmonella after MSC treatment. In both of these situations, there was a positive synergistic effect of the gentamicin and MSC treatments. When Salmonella was given after MSC treatment, the MSC alone reduced cecal colonization from Log10 6.01 to Log10 1.99, compared to Log10 1.42 for the combination of gentamicin and MSC. When Salmonella was given before MSC treatment, the MSC alone reduced cecal colonization from Log10 6.31 to Log10 4.69 compared to Log10 0.83 for the combination of gentamicin and MSC. The use of in ovo gentamicin did not adversely affect the effectiveness of MSC as had been reported for other products, and the combination of gentamicin and MSC was very effective in preventing Salmonella colonization when chicks were exposed to the Salmonella before the MSC.