Effect of feeding a Saccharomyces cerevisiae fermentation product on immune response to vaccines against Newcastle disease virus, Avian influenza virus, and the prevalence of chronic respiratory disease and coccidiosis in chickens raised in a low bio

This study was carried out in a low biosecurity production system to explore the effects of a Saccharomyces cerevisiae fermentation product (SCFP) on immune responses to vaccination against Newcastle disease virus (NDV) and Avian influenza (H5N1) and prevalence of common diseases in chickens including chronic respiratory disease (CRD) and coccidiosis. One hundred and ninety two 1-day-old chickens were randomly assigned into control (a standard basal diet) and treatment (a standard basal diet containing 1.25 kg/MT of Diamond V XPC™ – a Saccharomyces cerevisiae fermentation product). Immunity data on antibody titers to NDV and H5N1 were collected at 3 weeks and 10 weeks post vaccination for H5N1 and at 1 week and 6 weeks post vaccination for NDV. The sero-prevalence of CRD were detected at 5 weeks of age by ELISA. The incidence of coccidiosis infection was evaluated by weekly oocyst counting starting from 2 weeks of age. Results showed that supplementation of SCFP did not affect the immune response to vaccination with NDV and H5N1 vaccines (P > 0.05). The sero-prevalence of CRD infection was similar between treatment groups fed diets with and without SCFP supplementation, while the intensity of coccidiosis infection tended to be higher in the SCFP supplementation compared to the control. Overall, supplementation of the SCFP in the diet did not affect immune response to NDV and H5N1 post-vaccination, and the prevalence of CRD.