Hepatic enzyme specific activities and fasting metabolic rate in pullets fed on controlled amounts of food during growth and lay

Abstract

Variations in growth rate and daily egg output during lay were obtained by feeding controlled amounts of food to egg-type pullets from 6 to 70 weeks of age. Prior to sexual maturity the weight and lipid content of the liver were significantly increased when growth rate was severely restricted. These changes were associated with increases in the specific activities of hepatic lipogenic enzymes. Changes in hepatic enzyme specific activities in response to restricted feeding during growth were small compared with the increases observed at sexual maturity. During lay, restricted feeding had no significant effect on the liver lipid content or hepatic enzyme specific activities, but the specific activities of all the hepatic enzymes examined declined with age after sexual maturity. Restricted feeding had no influence on the fasting metabolic rate at any age. A reduction was observed between 13 and 20 weeks of age, but after a small increase at sexual maturity little further change was noted.