Factors affecting the concentration of testosterone in poultry litter

Poultry litter used as cattle feed can contain high levels of testosterone (>400 ng/g) and estrogen (>300 ng/g)which can interfere with reproduction. However such high levels of testosterone are not usually found in broiler chicken litter (< 6% of samples). We tested the following parameters to determine what factors could be responsible for highly elevated concentrations of testosterone: sex, age, fermentation. It was found that (1) there is no difference in testosterone content in poultry litter obtained from male (133±12 ng/g) or female broilers (133±13 ng/g); (2) poultry litter from adult roosters have unacceptably high levels of testosterone (670±95 ng/g) and layers have high levels of estrogens (533±50 ng/g); (3) although fermentation of poultry manure generally lowers steroidal hormone content, if antibiotics are added to the incubation, there was a a five-fold increase in radioimmunoassayable testosterone content (controls 94±6 ng/g vrs treated 578±80 ng/g).