| dc.description.abstract | The principal objective of this investigation was to evaluate coccidiosis vaccination, with or without probiotic administration, for effects on broiler performance and clinical indices of infection due to field strain Eimeria challenge during pen trials of commercially applicable durations. During trials 1 and 2, body weights of vaccinated broilers were reduced (P<0.05) compared to other experimental groups during rearing through the grower phase. Final body weights, however, were not different among experimental groups at the termination of each trial. Similarly, feed conversion in trials 1 and 2 was increased (P<0.05) in vaccinated broilers during rearing through the grower phase when compared to non-vaccinated broilers. Significant improvements (P<0.05) in feed conversion were measured in trials 1 and 2 in vaccinated broilers during the withdrawal phase of grow-out. Probiotic administration significantly reduced (P<0.05) feed conversion during the withdrawal phase of trial 2. During trial 3, body weights of broilers in the vaccine with probiotic (water) group were higher (P<0.05) at termination (d 44) than all other experimental groups and equivalent to the ionophore alone and ionophore with probiotic groups. Similarly, cumulative mortality corrected feed conversion ratio (FCR) was lower (P<0.05) in broilers from the vaccine with probiotic (water) group compared to negative controls, and not different from FCR in ionophore administered broilers.
Trial 2 observations revealed body weight gains among vaccinated broilers that were significantly increased (P<0.05) during a seven day clinical field strain Eimeria challenge period compared to non-vaccinated broilers. Both probiotic and vaccine significantly decreased (P<0.05) gross lesion scores in upper and mid-intestinal regions. A significant reduction (P<0.05) in gross lower intestinal lesion score was also observed in the vaccine alone group. In Trial 3 general observations showed, broilers in the ionophore alone group were associated with higher (P<0.05) microscopic mid and lower intestine lesion scores when compared to broilers receiving vaccine or vaccine + probiotic. These data suggest that co-administration of probiotic during coccidiosis vaccination results in performance parameters that are improved when compared to vaccination alone and indistinguishable from protection conferred by feeding an ionophore in the presence of field strain Eimeria. | en |
