Towards a better understanding of muscle and adipose tissue development: a prerequisite to control the quality of carcasses and meat / flesh in livestock

Abstract

The qualities of carcasses and products of agronomic species depend largely on characteristics and relative proportions of the different tissue components, mainly muscle fibers, muscular connective tissue and adipose tissues. This review is devoted to the prenatal and neonatal development of these three components. The embryonic origin of myofibers and connective tissue from trunk muscle differs from that of limb and head muscles. The embryonic origin of white adipocytes remains to be established and may depend on the anatomical location of adipose tissues. The post-embryonic growth of muscles and adipose tissues involves the proliferation and then the differentiation of fetal or adult progenitors. The total number of muscle fibers is fixed at around 66% (bovine) or 80% (pig) of gestation or at birth in poultry, while it increases after hatching in some fishes. The number of adipocytes increases predominantly during fetal growth and to a lesser extent after birth. Interactions between tissues during growth, formerly suggested, have now been demonstrated by the identification of proteins secreted by muscle and adipose cells that participate in the cross-talk between tissues.