Gross lesions and histopathological findings after inoculation of Eimeria acervulina, E. maxima and E. tenella in broiler chicks

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This experiment was aimed at counting excreted oocysts and evaluating the gross lesions and histopathological changes in broiler chicks infected with Eimeria; E. acervulina (Ea), E. maxima (Em) and E. tenella (Et). Twelve-day-old broiler not infected with Eimeria spp. were used in this experiment. At day 12, the birds in group Ea (n=3), Em (n=3) and Et (n=3) were inoculated with 5 × 10 3 sporulated oocysts of Ea, Em and Et per 1 mL of tap water orally and control chick was injected tap water of equal amount. The prepatent period (PP) for Ea, Em and Et were four, five and six days, respectively. To evaluate the progress of the coccidiosis, post-mortem analysis method and histopathological evaluation were performed on two days after PP of Ea and Et, and three days after PP of Em at two-day intervals on one bird from each group. Intestinal segments (Ea, duodenum and upper intestine; Em, mid intestine; and, Et, cecum) of all chicks were obtained from the autopsied birds. Among pathological changes of coccidiosis, target parts of small intestine and caecal pouches were found mucosal petechiation and white plaques streaks in duodenum. Histopathological evidence showed upper small intestinal villus preserved with different phases of parasite (zygotes, oocysts, macro- and micro-gametocytes) after infection with Ea in broiler chicks. Zygotes in the lamina propria and fusion of middle small intestinal villi in broilers infected with Em and invasion of the caecal crypt of oocysts and granulomatous inflammation of caecal submucosa in broilers infected with Et were found.