TIBIAL DYSCHONDROPLASIA OF CHICKENS INDUCED BY FUSAROCHROMANONE, A MYCOTOXIN

Chicks were fed for 3 weeks a practical broiler starter diet amended w ith fusarochromanone (FC), a mycotoxin. In Hubbard broiler chicks, the highest test dose of FC (75 ppm) suppressed body weight by 33% and hu moral response to sheep erythrocytes by 34% to 50%, and increased the incidence of tibial dyschondroplasia (TD) to 100%. The intermediate do se (35 ppm) significantly increased the incidence of TD in both types of broiler chicks (Hubbard and Indian River), but its effect on humora l response to sheep erythrocytes was not consistent across several exp eriments. A minimum dietary concentration greater than 20 ppm was requ ired to significantly increase the incidence of TD. Excessive dietary copper or zinc (200 ppm) alleviated the effect of FC on TD. However, a ctivities of copper-dependent ceruloplasmin and superoxide dismutase w as not affected by FC. Cartilage mineral profiles in FC- or Thiram-ind uced TD differed from that of 1-day-old hypertrophic embryonic cartila ge core (less K and Mn). FC did not induce TD in leghorn chicks.