TY JOUR TI THE ENVIRONMENTAL ECOLOGICAL FACTORS INFLUENCE ON THE CORTICOSTEROID ACTIVITY OF AMERICAN MINKS (MUSTELA VIZON SCHR.) AND SILVER-BLACK FOXES (VULPES VULPES L.) KW American mink KW silver-black fox KW corticosteroids KW stress KW blood serum KW ecological factor JO Bulletin of KSAU AU Berdnikov, P.P. AU Sanzhiyeva, S.E. PY 2012 IS PB Krasnoyarsk State Agrarian University