OSSIFICATION AND GROWTH OF THE RIBS AND STERNUM IN PREHATCHING PERIOD OF THE HUBBERT STRAIN BROILER

Recent researches in experimental embryology of avian species have particularly investigated skeletal mutations, development of cultured embryos under artificial conditions, and teratogenic consequences of new drugs. Data on the normal skeletogenous stages are also essential parameters to interpret and elucidate the data acquired on these studies. Accordingly, a number of 10 embryos were prepared every 24 h from 10 to 20 days of incubation, to report the ossification and growth of the ribs and sternum of the Hubbert strain broiler (JV). The embryos fixed in 10% formaldehyde then 95% ethanol solutions were cleared and the skeletons of the embryos were stained in toto with Alcian blue&alizarin red for cartilage and ossified components, respectively. Observation of the skeletons photography were performed under a stereoscopic microscopy, paying particular attention to the timing of chondrification and ossification of the bones. The first occurrence of the ossification was observed in the ribs on the 11t h day of incubation. Those in the sternum were seen on the 15th day. We observed in this study that the uncinate processes of the ribs showed very early chondrification and ossification. The ossified components continued to develop until the 20t h day of incubation when the hatching took place.