Recommended assay for treatment of chicks to prevent Salmonella colonization by ‘competitive exclusion
- G. C. Mead, P. A. Barrow, +6 authors N. J. Stern.
- J. Food Prot. 52:500–502.
The efficacy of the commercial competitive exclusion product Broilact against Campylobacter jejuni was evaluated in broiler chickens in a 5-week pilot-scale study. Newly-hatched broiler chicks were brought from a commercial hatchery. After arrival 50 seeder chicks were challenged orally with approximately 10(3) cfu of C. jejuni, wing marked, and placed back in a delivery box and moved to a separate room. The rest of the chicks (contact chicks) were placed in floor pens, 100 chicks per pen. Birds in two pens were treated orally on the day of hatch with the commercial competitive exclusion (CE) product Broilact, and three pens were left untreated. The following day 10 seeder chicks were introduced into the Broilact treated and untreated control pens. One pen was left both untreated and unchallenged (0-control). Each week the ceca of 10 contact chicks and one seeder chick were examined quantitatively for Campylobacter The treatment prevented or significantly reduced the colonization of the challenge organism in the ceca during the two first weeks; the percentage of colonized birds being 0% after the first week and 30% after the second week in the Broilact treated groups but was 100% in the control groups the entire 5-week rearing period. During the third rearing week the proportion of Campylobacter positive birds started to increase in the treated pens, being 80% after the third week and 95 and 90% after the fourth and fifth rearing weeks, respectively. Similarly the average count of Campylobacter in the cecal contents of the Broilact treated chicks started to increase, the difference between the treated and control chicks being 1.4 logs at the end of the rearing period. Although the protective effect was temporary and occurred only during the first two weeks of the rearing period, the results of this study support the earlier observations that CE flora designed to protect chicks from Salmonella may also reduce Campylobacter colonization of broiler chickens.