The cellular basis for growth of the abdominal fat pad in broiler-type chickens.

Cellular growth of the abdominal fat pads from Tegel TM70 white broiler chickens was characterized by both hyperplasia and hypertrophy of adipose cells until the chickens were approximately 14 weeks old, after which hypertrophy of existing adipose cells was solely responsible for increases in the mass of these fat deposits. The percent body fat was linearly and positively correlated with the weight of abdominal fat. However, at a constant percent body fat, male birds had a larger deposit of fat in the abdominal region than did females. Thus, a different relationship to predict body fat would be required for each sex. In mature birds the mass of an adipose tissue deposit is generally reflected in the size of adipose cells rather than the number of cells in an adipose organ.