关键词: 鹅, Eimeria nocens, 生活史, 致病性

Abstract: Sixteen 10-day-old artificially-reared coccidia-free goslings were inoculated orally with 1.0×105-1.0×106 sporulated oocysts of Eimeria nocens，respectively, and killed at intervals from 30 h to 336 h after inoculations. The life cycle and pathogenicity of E. nocens were observed chronologically. The results showed that at least 3 generations of meronts developed in the endogenous stage of the life cycle of E. nocens. Two types of meronts were found. The first completed maturation at 54 to 78 h after inoculation. These meronts were the first generation meronts, each forming about 10 merozoites. The second completed maturation at 102 to 240 h after inoculation. These meronts were the second or third generation meronts, each forming about 25 merozoites. Development of gametes began at about 198 h after infection. The prepatent period was 9 d and discharge of oocysts continued for 4 d. Sporulation of oocysts occurred in 60-72 h at 25℃. E. nocens invaded posterior jejunum, ileum, ceca, rectum and cloaca. Developmental stages were localized within the epithelial cells of villi and crypts and in lamina propria. Marked histopathological changes including desquamation and necrosis of intestinal epithelium, submucosal edema, hemorrhages, infiltration of inflammatory cells and villous atrophy presented during the periods of late merogony, gamogony and oocyst shedding, but most pronounced in the ileum and the regions adjacent to it. The infected goslings showed severe diarrhoea with necrotic epithelium and blood in the feces, anorexia, emaciation and even deaths, suggesting that E. nocens is highly pathogenic for goslings.

Key words: Gosling, Eimeria nocens, Life cycle, Pathogenicity