Adipocyte Size and Number in Mature Broiler-Type Female Chickens Subjected to Dietary Restriction during the Growing Period

Broiler-type chickens were subjected to dietary restriction for up to 14 weeks. Body weights and composition were measured in the birds at 42 weeks of age. The body weights of birds subjected to feed restriction from day-old to 12 and 14 weeks of age remained significantly lower than those of the control birds. The lighter weights appeared to be due to a reduction in the growth of all tissues, since the proportional weights of the M. pectoralis major, liver, reproductive tract, tibiotarsus, and adipose depots were similar in the restricted and the control birds. Adipocyte size in the retroperitoneal depot increased in the birds on all treatments between 18 and 42 weeks of age. Dietary restriction for 12 and 14 weeks suppressed adipocyte growth and the effect on cell size was still apparent in the retroperitoneal and the M. sartorius adipose depots when the birds were 42 weeks old. Adipocyte numbers in the retroperitoneal depot were significantly greater in the birds subjected to feed restriction for 12 and 14 weeks. The increase in retroperitoneal adipocytes in these birds was caused by an increase in the number of small cells. The number of large retroperitoneal adipocytes in the birds on restricted feed intake for 14 weeks was greatly reduced. Adipocyte numbers in the M. sartorius depot were not affected by feed restriction for up to 14 weeks.