The Effects of Feed Intake on Adipocytes in the Abdominal Fat Pad of Mature Broiler-Type Female Chickens

Abstract

One thousand broiler-type pullets were reared with feed restriction from 5 weeks of age to attain a target average body weight of 1.64 kg at 18 weeks of age. Thereafter feed was supplied at the rate of 130 g per bird per day until 47 weeks at which time half the population was fed ad libitum. An additional treatment was imposed at 86 weeks when 12 birds were gradually but severely restricted in feed intake until, by 97 weeks, they were receiving only 40 g feed per day. Birds restricted in feed intake until 47 weeks and then fed ad libitum increased consumption sharply and in proportion to body weight for approximately 2 weeks. Thereafter, intake declined to about 20% in excess of the restricted level for the next 16 weeks. Body weight increased with the increased feed intake. Average adipocyte diameter increased with the age of the birds even when feed was restricted. There was no increase in the number of adipocytes present in the retroperitoneal fat pad after 27 weeks of age. The size distribution of adipocytes was consistently bimodal except following severe feed restriction when the weight of the fat pad regressed and the secondary peak of small adipocytes disappeared.