title: The relationship of circulating levels of estrogens, corticosterone and calcium to production performance of adult turkey hens under conditions of increasing ambient temperature.
abstract: Turkey hens were exposed to stepwise increases in ambient temperature from 21degreesC. to 25degreesC. to 30degreesC. to 35degreesC. at two-week intervals. Dietary calcium levels of 1.54, 2.01 and 2.48% were fed. Production data and circulating levels of estrone, estradiol-17-beta, corticosterone, total calcium, bound calcium, and unbound calcium were studied. The dietary calcium levels had no significant influence on any of the results. The temperature increase caused a significant (P less than .05) decrease in plasma levels of calcium and estrone, egg production, shell thickness and egg weight. The temperature increase caused a significant (P less than .05) fluctuation in plasma corticosterone levels but had no apparent effect on the plasma estradiol levels. With the temperature increase, unbound plasma calcium levels and plasma corticosterone levels showed a significant (R greater than or equal to 0.50, P less than 0. less than .01) positive correlation to egg production.
mesh_terms: D000818:Animals; D002118:Calcium / Q000097:blood*; D002136:Calcium, Dietary / Q000008:administration & dosage; D003345:Corticosterone / Q000097:blood*; D004528:Egg Shell; D004531:Eggs; D004781:Environmental Exposure; D004958:Estradiol / Q000097:blood; D004967:Estrogens / Q000097:blood*; D004970:Estrone / Q000097:blood; D005260:Female; D010058:Oviposition; D013696:Temperature; D014422:Turkeys / Q000097:blood / Q000502:physiology*
chemical_list: D002136:Calcium, Dietary; D004967:Estrogens; D004970:Estrone; D004958:Estradiol; D002118:Calcium; D003345:Corticosterone