Effects of long-term food restriction on energy expenditure and thermoregulation in broiler-breeder fowls (Gallus domesticus).
1. From 2 to 21 weeks of age, 150 female broiler-breeder chicks received one of three dietary treatments. Fifty received an ad libitum supply of food (treatment AL). The remaining 100 were given weighed (restricted) rations once a day, 50 receiving the amount per bird recommended in the Ross 1 Parent Stock Management Manual (treatment R) and the other 50 receiving twice this recommended amount (treatment 2R). Water was provided ad libitum for all treatment groups. 2. The daily allowance for R birds increased from 26 g per bird at 2 weeks of age to 94 g at 21 weeks. The intake of AL birds meanwhile increased from 65 g at 2 weeks to 240 g at 19 weeks, before decreasing to about 200 g at 21 weeks. 3. Median heat productions (H) per bird in the R and 2R treatment groups were, respectively, 65 and 40% lower than in the AL when adjustment was made for the reduced food intake of AL birds in the calorimeter chambers. The effects of dietary treatment on fasting H were proportionally similar. 4. Because the increasing divergence in body weights would have made a large contribution to differences in H per bird, the results were adjusted to the median weight of 2.03 kg and to unit weight (1.00 kg). Adjusted fasting heat production was 18 and 11% less in 2R and R birds than in those fed ad libitum.(ABSTRACT TRUNCATED AT 250 WORDS)
MacLeod
M G
MG
AFRC Roslin Institute (Edinburgh), Roslin, U.K.
Savory
C J
CJ
McCorquodale
C C
CC
Boyd
A
A
D000821:Animal Feed; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001835:Body Weight; D002151:Calorimetry; D002645:Chickens / Q000502:physiology*; D004734:Energy Metabolism; D005260:Female; D005508:Food Deprivation / Q000502:physiology*