Fatness in chickens : metabolic and genetic features

Abstract

Increase in adipose tissues in meat-chicken carcasses has prompted investigations in order to control this unfavourable trait, to the benefit of both producers and consumers. Comparisons between experimental lean and fat chicken strains have pointed out the main metabolic differences between lean and fat birds. The main results are recalled. In addition, recent results regarding hepatic enzyme activities and mRNA amounts involved in various metabolic steps (amino acid catabolism, lipogenesis per se, lipid maturation and secretion) are reported. Many of these measurements are higher in fat chickens compared than in lean ones. A hypothesis of a common regulation of these different metabolic steps, explaining most of the differences, is proposed. Each step could, however, be individually responsible for fatness variability as it seems to occur for the glutamate desydrogenase enzyme.