The effect of salinomycin on Salmonella, Campylobacter and the intestinal microflora in experimentally infected broiler chickens

The effect of the ionophore coccidiostat salinomycin on infections with Salmonella or Campylobacter was investigated in two experimental infections studies. In addition, the effect on the natural populations of Clostridium perfringens and lactobacilli in the intestine was examined. In both infection studies, chickens were divided into six groups and kept in separate isolators from day-old. Two groups of birds received salinomycin in their feed (75 mg/kg) from day 8, whereas the remaining four groups were given feed without any antibiotics or coccidiostats. At day 14 chickens were infected with approximately 10 cfu of either Salmonella Typhimurium or Campylobacter jejuni. Control birds were given sterile saline. Once a week 6 birds from each group were killed and intestinal bacteria were enumerated by cultivation from ileum and caecum. We found that chickens given salinomycin gained significantly more weight than control birds. Lactobacilli were found in high amounts in all samples but no effect of salinomycin on lactobacilli counts was detected. Likewise, we found no effect of salinomycin on the course of a C. jejuni infection. However, a significant reduction of the numbers of C. perfringens, was observed in the groups receiving salinomycin.