Concentration of nuclei in chicken muscle fibre in relation to the intensity of growth.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt età la diffusion de documents scientifiques de niveau recherche, publiés ou non, ´ emanant desétablissements d'enseignement et de recherche français oú etrangers, des laboratoires publics ou privés. SUMMARY In chickens sharply differing in growth intensity, the nuclear concentration on a constant length segment of muscle fibre released by maceration has been investigated. At the same time DNA concentration in muscular tissue and the frequency of e H-thyxnidine labelled nuclei in the individual groups have been examined. The content of nuclear component converted to volume unit of the fibre decreased in the course of the investigated period. The lowest values of this nucleo-plasmatic ratio were found in chickens with the highest intensity of growth. The tendency of changes in DNA concentration of the muscle tissue are in approximate agreement with these observations. In the course of the investigated period a decline in the frequency of 3 H-thymidine labelled nuclei has been observed. Differences in the share of labelled nuclei positively corresponding to the intensity of growth in the individual groups appear only in 7-day old chickens. The hypothesis is suggested that during the period of low proliferation level there may exist local differences of incorporation frequency in the muscle.