Metabolic and anatomical adaptations of heavy-bodied chicks to intermittent feeding. I. Food intake, growth rate, organ weight, and body composition.

Chicks of a heavy-bodied strain were deprived of food on alternate days from 14 to 83 days of age. Relative food intake was depressed by intermittent feeding to 25 days of age, after which the deprived chicks resumed the relative intake of the ad libitum-fed controls, i.e., the relative intake on repletion day was twice that of the control chicks. Following an adaptation period of 2 weeks, the relative growth rate of the intermittently fed chicks exceeded that of the control group, the excessive growth being due to an increase on the day of repletion which was more than twice that of the control birds. Body fat concentration was depressed by intermittent feeding throughout the experimental period. Although, in ad libitum-fed chicks, periodical deposition of body protein and fat was parallel throughout the experimental period, in the treated chicks, protein deposition prevailed initially and fat deposition prevailed at the end of the experimental period. Intermittent feeding was accompanied by a consistent increase in the relative weight of the liver, pancreas, and gastrointestinal tract, including the small intestine. The differences in food intake, growth, body composition, and gastro-intestinal tract between heavy- and light-breed chicks exposed to intermittent feeding are discussed.