COMPARATIVE HISTOLOGICAL AND HISTOMORPHOM ETRICAL STUDIES OF THE TIBIAL DIAPHYSEAL GROWTH IN 2 TURKEY STRAINS BETWEEN THE 3RD AND THE 12TH WEEKS OF AGE

The comparative cortical growth of the tibiotarsus was studied in 2 tu rkey strains, one light, one heavy, between 3 and 12 weeks or age, usi ng histological and histomorphometrical methods. The growth in thickne ss started earlier and was much faster and larger in the heavier turke y strain. The early ovoid shape of the cortex of the heavier strain an d the difference between the thickness of the narrow and the thick cor tical faces seemed to be related to the action of strong mechanical st rains. Nevertheless the diaphyseal cortical ratio remained not signifi cantly different in the 2 strains from the age or 3 weeks. The light s train exhibited during all the studied periods indicated a more variab le mineral apposition rate and earlier and more extensive bone remodel ling phenomena. Most of the growth in thickness parameters were signif icantly higher in the heavier strain when turkeys of the 2 strains wer e compared at an equivalent weight.