EFFECT OF FULL FEED AND EARLY FEED RESTRICTION ON BROILER PERFORMANCE, ABDOMINAL FAT LEVEL, CELLULARITY, AND FAT-METABOLISM IN BROILER-CHICKENS

Three hundred sixty Peterson x Arbor Acres chicks were fed two feed re gimens to compare their effects on adipose cellularity, adipocyte lipo lysis, hepatic glucose oxidation, adipocyte lipogenesis, bird performa nce, and abdominal fat level Broilers in the first regimen had ad libi tum access to feed throughout the 7-wk experiment, whereas broilers in the second regimen consumed feed at will throughout the experiment ex cept that they were subjected to feed restriction (1.49 kcal/g BW2/3 d aily) from 7 to 12 d of age (DOA). No differences in mean body weights were observed between the full-fed and restricted males and combined sex broilers at 49 DOA. Feed conversion and abdominal fat levels of fe male and combined sex were lower (P < .05) for the restricted than ful l-fed broilers. No differences in adipocyte numbers based either on wh ole abdominal fat pads at 28 and 42 DOA or per gram fat at 42 DOA were observed between broilers fed the two feed regimens. However, the adi pocyte numbers per gram fat at 28 DOA were greater (P < .05) for the r estricted broiler than for the broilers that ate freely. Lipolysis bas ed per million adipocytes was not different between the treatments at 28 and 42 DOA; however, lipolysis based on per gram adipose tissue was increased (P < .05) with the addition of isoproterenol and theophylli ne for the restricted broilers compared to the full-fed broilers at 28 DOA. No difference was observed between the feed regimens at 42 DOA w ith hormone addition. Lipogenesis of the restricted broilers was lower (P < .05) than that of the full-fed broilers at 14 and 56 DOA. No dif ference in glucose oxidation was found between chickens fed the two re gimens. Reduced abdominal fat in the restricted broilers is attributed to the reduction of adipocyte volume, which may be due to decreased l ipogenesis.