Application of direct-fed microbial bacteria and fructooligosaccharides for Salmonella control in broilers during feed withdrawal

Providing direct-fed-microbial (DFM) bacteria and fructooligosaccharides (FOS) for the control of potential escalation of Salmonella colonization during simulated feed withdrawal and confinement was assessed. Eight hundred and eighty broilers (16 pens; 55 chicks per pen) were reared to 6 wk of age. Chicks were sprayed with a solution containing 10(6) nalidixic-acid resistant Salmonella typhimurium(NR) cells per milliliter on the 2nd d after hatching. Because this first challenge did not yield a high infection rate, chickens were rechallenged per os at Day 18 by providing water containing 10(7) cells of S. typhimurium(NR) per milliliter. At 3 and 5 wk of age, 10 birds per pen were euthanatized and cecal Salmonella were quantified (log colony-forming units per gram). Feed was removed from all pens at 6 wk, and pens were randomly assigned to be either the treatment group or the control group. The treatment groups were provided a DFM (mixture of nine bacteria) and FOS 50(R) (10%) in the drinking water. The control groups received drinking water only. After 6 h of feed withdrawal, chickens were cooped (eight per coop) and held 10 h. Immediately after confinement, 10 chickens were used for cecal enumeration of S. typhimurium(NR) Salmonella colonization declined from 99% at 3 wk to 44% at 5 wk. After feed withdrawal, application of the treatment, and confinement, 11 and 14% of the treated and control groups, respectively, yielded S. typhimurium(NR) by direct plating from ceca (3.87 and 3.75 log(10) cfu/g, respectively). No difference (P > 0.05) in Salmonella colonization occurred between the treated and the control groups; however, enrichment of ceca (incubation in nutrient broth at 37 C for 24 h) yielded a higher incidence of S. typhimurium(NR) in the control groups (32% in the treated vs 51% in the control). Ceca weights were greater in the treated group (P < 0.05). Simulated feed withdrawal and confinement did not escalate Salmonella colonization in the chicken ceca.