SEX AND GENOTYPE DEPENDENCE ON THE EFFECTS OF LONG-TERM HIGH ENVIRONMENTAL TEMPERATURES ON CELLULAR ENZYME-ACTIVITIES FROM CHICKEN ORGANS

The effects of long term hyperthermia on enzyme levels in the chicken heart and breast muscles, brain, kidney, liver and lung, in relation t o sex and degree of feathering, were studied. The enzymes studied were alanine and aspartate aminotransferases, alkaline phosphatase, creati ne kinase, lactic dehydrogenase and gamma-glutamyltransferase. Double heterozygote frizzled naked neck and normally feathered male and femal e broilers were exposed to 24 degrees C (control group) and 32 degrees C (experimental group), for 5 weeks, starting at the age of 3 weeks. The birds were killed, the tested organ removed, homogenized and cell- free supernatant was obtained by centrifugation. Enzyme activities wer e measured with an autoanalyser and specific activities were calculate d. Prolonged heat stress resulted in changes of enzyme activities in a ll the tissues studied. No significant differences were seen in the ce llular enzyme levels from the various organs between male and female b irds unexposed to heat stress. Following heat stress, however, greater changes in enzyme levels were seen in the brain, heart muscle and kid ney of males compared to females. No significant differences were seen in the cellular enzymes studied in the tissues between the normal and frizzled naked neck chicken. Following prolonged heat stress, there w ere some differences in the degree of response between the frizzled na ked neck and control groups. These differences did not show a consiste nt or clear pattern indicative of the degree of stress in each of the groups.