Reprod. Nutr. Dev. 42 (2002) 415-431
DOI: 10.1051/rnd:2002035

Muscle fibre ontogenesis in farm animal species

Brigitte Picard^a, Louis Lefaucheur^b, Cécile Berri^c and Michel J. Duclos<sup>c

a</sup>  INRA, Unité de Recherche sur les Herbivores, Theix, 63122 Saint-Genès-Champanelle, France
^b  INRA, Unité Mixte de Recherches sur le Veau et le Porc, 35590 Saint-Gilles, France
^c  INRA, Station de Recherches Avicoles, 37380 Nouzilly, France

Abstract
In farm animals (bovine, ovine, swine, rabbit and poultry), muscle fibre characteristics play a key role in meat quality. The present review summarises the knowledge on muscle fibre characteristics and ontogenesis in these species. Myofibre ontogenesis begins very early during embryonic life, with the appearance of two or three successive waves of myoblasts which constitute the origin of the different types of muscle fibres. In small animals (rodents and poultry), a primary and a secondary generation of fibres arise respectively during the embryonic and foetal stages of development. In the largest species (bovines, sheep, pigs) a third generation arises in the late foetal or early postnatal period. Following these two or three waves of myogenesis, the total number of fibres is fixed. This occurs during foetal life (bovines, ovines, pigs and poultry) or during the first postnatal month in rabbits. Contractile and metabolic differentiation proceed by steps in parallel to myogenesis and are partially linked to each other. In bovines and ovines, the main events occur during foetal life, whereas they occur soon after birth in the pig, poultry and rabbit, but some plasticity remains later in life in all species. This comparative survey shows that the cellular processes of differentiation are comparable between species, while their timing is usually species specific.

Key words: myogenesis / myofibre / myosin / species

Correspondence and reprints: Brigitte Picard
    e-mail: picard@clermont.inra.fr

© INRA, EDP Sciences 2002