78 adult roosters and a single factorial design were used to study the effects of ambient temperature on apparent and true metabolizability of dry matter (ADMR, TDMR), apparent and true metabolizable energy (AME, TME), excretory amounts of endogenous dry matter and energy (EDM, EEL), plasma thyroid hormone (T_3、T_4) concentrations and toexplore the relationship between plasma thyroid hormones and ADMR, AME, EDM, EEL, TDMR. TME. Ambient temperature were 5~10C、10~15C、15~20C、20~25℃、25~30℃、30~35C。 Ambient tempe...