Morphogenesis of Fusarium sp-Induced Tibial Dyschondroplasia in Chickens

Abstract

Tgibial dyschondroplasia was induced in female broiler chicks by the incorporation of 2% Fusarium roseum “Alaska” culture into their starter ration. Chicks were placed on this diet at one day of age and maintained until they were killed at four days or one week. Proximal tibial physes were grossly thickened into cone-shaped masses of cartilage by one week of age. Microscopically, lesions were in both ages of treated chickens and were characterized by thickening of the transitional zone which was especially prominent in the center of the growth plate. This zone was unmineralized, avascular, and contained chondrocytes which were crenated and densely eosinophilic. The cartilage matrix was pale and contained some patchy eosinophilic foci. Four growth plates with tibial dyschondroplasia and four normal growth plates from each of the four-day and one-week-old age groups were evaluated based on the following parameters: number of metaphyseal vascular sprouts, distance between the proliferative/transitional junction and the tip of the metaphyseal vascular sprouts, width of the tips of the metaphyseal sprouts, distance between tips of adjacent metaphyseal vascular sprouts, and number of perforating vessels in the proliferative zone. The distance between the proliferative/transitional junction and the metaphyseal sprout tips was greatly increased (p < 0.01) in the affected four-day and one-week-old chickens compared to age-matched controls. Fusarium sp-induced tibial dyschondroplasia morphologically resembles spontaneous and chloride-induced tibial dyschondroplasia and tibial dyschondroplasia may, therefore, represent a common end-point lesion derived by several pathogenetic mechanisms.