Morphometric and Histopathological Evaluation of a Probiotic and its Synergism with Vaccination against Coccidiosis in Broilers

A probiotic containing Bacillus mesentericus, Clostridium butyricum, and Streptococcus faecalis [AVITEAM] was evaluated in damage control and synergism with vaccination against coccidial infection in broilers, using morphometric measurements and histopathological observations. It was mixed in feeds and vaccination was done by inoculating birds with an attenuated live vaccine containing Eimeria tenella, E. acervulina, and E. maxima orally at 5-day-old. Experimental infection was produced by orally dosing oocysts of E. tenella and E. maxima at 28-day-old. Growth and feed consumption was measured and postmortem examinations: intestinal sizes, cecal oocysts per gram (OPG), intestinal microbial flora and IgA concentrations, lesion scores, morphometrics, and pathological scores of the intestine were performed at 36-day-old. After coccidia challenge, the probiotic and the vaccination reduced cecal OPG independently and synergistically. Total IgA in the small intestine was increased by the probiotic. The lesion score was reduced by the probiotic, not by the vaccination in the small intestine and by all three treatments in ceca. In microarchitecture, the villus height (V) was increased by the probiotic in the jejunum and decreased by the vaccination in the ileum, while the crypt depth (C) was not affected. The ratio of V/C in the jejunum was increased by the probiotic alone and further with vaccination, indicating synergism. In histopathology, exfoliation and degeneration of mucosal tissues were prevented by the probiotic but exaggerated by the vaccination, and villus atrophy was prevented by both in the jejunum. Vaccination effects were realized or further improved in combination with dietary probiotic in the OPG, cecal lesion scores, and the V/C ratio.