| Selected essential oils with proven in-vitro activity were mixed with feed in various combinations and at different concentrations, with and without emulsifiers. A series of experimental challenge studies (pigs exposed to SalmonellaTyphimurium DT104) were conducted to evaluate the clinical signs and level of Salmonella shedding in pigs receiving diets containing essential oils compared to pigs receiving a control diet. No differences in morbidity, clinical signs or Salmonella count from the cecal content were observed. Further experimental challenge studies using enterotoxigenic Escherichia coli O149:K91:F4 were used to evaluate the efficacy of a commercial product containing oregano oil, thyme oil, and cinnamon. The inclusion of the herbal product to starter feed did not prevent diarrhea and performance was similar to control animals. It was concluded that under the circumstances of these trials essential oils did not appear to be of value in controlling salmonellosis or colibacillosis. |
