| Popis: |
We evaluated the effects of treatment with the probiotic Preempt on day of hatch, maternal vaccination with the bacterin, Layermune SE, and the combination of these on cecal colonization of broiler chicks at various ages by Salmonella. Chicks were challenged by adding Salmonella colonized chicks (seeder chicks) 3 d after hatch. Salmonella typhimurium and Salmonella heidelberg were the challenge organisms in the first two and last two of the four trials, respectively. Data from 286 treated broiler chicks and 48 seeder chicks were analyzed. Preempt treatment of chicks reduced cecal colonization levels by Salmonella about 1.5 log cfu or 95% at 2, 4, and 6 wk of age. The reductions varied slightly due to age, trial, and degree of colonization. Reductions in colonization levels of Salmonella colonized seeder chicks housed at 3 d with Preempt-treated broilers indicated that the seeder chicks benefit from the treatment of pen mates. Maternal vaccination by injecting bacterin was effective for elevating antibody titers against Salmonella enteritidis in chicks as well as hens. However, it had no impact on the cecal Salmonella colonization of the tested chicks, either directly or in conjunction with (no interactions) any of the other variables examined. Average reductions in cecal Salmonella colonization for 2-wk intervals after chicks were 2 wk old were about 1.5 log cfu in the probiotic-treated and control groups. Differences due to Salmonella challenge serotype were minor. |
