Hormonal Activity in Poultry Excreta Processed for Livestock Feed

Abstract

Experiments were conducted to determine the kind and amount of endogenous hormonal activity present in various sources of poultry excreta processed for use as livestock feed. These experiments were conducted to determine: 1) the presence of both androgenic and estrogenic activity in poultry excreta; 2) the amount of activity found; and 3) the effect of processing methods, such as dehydration, upon the level of hormonal activity. Experiments in which chick comb growth was bioassayed showed that caged laying hen excreta processed by house fly larvae contained androgenic activity that ranged from 2.18 to 9.36 μg. of testosterone equivalents per gram of dried excreta. This activity was not present in fresh excreta and was not affected by drying times or temperatures up to 48 hr. at 100°C. In rat uterine growth assays, fresh, dried caged laying hen excreta contained up to 1.6 μg. of estradiol equivalents per gram of dried excreta. Holding excreta for 5 to 7 days under wither aerobic or anaerobic conditions reduced estrogenic activity, but drying temperatures up to 100° C. did not appear to affect the level of these hormones in excreta.