Adverse effects of aflatoxin B-1 on skeletal muscle development in broiler chickens

1. Detrimental effects of in ovo administrated of aflatoxin B-1 (AFB(1)) on the embryonic development of skeletal muscle were determined using histological methods. 2. A total of 420 eggs of a Ross broiler parent stock were incubated and divided into 4 groups: (1) control, (2) 5ng AFB(1)/egg group, (3) 15ng AFB(1)/egg group, (4) 40ng AFB(1)/egg group. Test solutions were injected via the air-sac, just prior to setting the eggs in the incubator. 3. Five eggs from each group were opened on different days of incubation (11d, 13d, 17d and 21d). Developmental stages of embryos were determined according to the Hamburger-Hamilton scale and embryos were weighed. Skeletal muscle tissue samples were dissected and fixed, sectioned and stained with Crossman's trichrome and AgNOR. 4. The mean relative embryo, leg muscle and breast muscle weights of AFB(1)-treated groups were lower than the control group and decreased with increasing AFB(1). The nucleus area and AgNOR area of the AFB(1)-treated groups were also lower than the control group whereas there were no significant differences in AgNOR numbers and AgNOR area/nucleus area among the treatment groups. 5. It was concluded that in ovo administrated of AFB(1) adversely affected the embryonic development of skeletal muscle and that affected animals might therefore be more susceptible to skeletal and muscle disorders during the growing period.