Morphological Study of The Skeletal Development in Duck Embryo (Anas platyrhynchos domesticus)

Abstract

The present study is one of the recent researches in the experimental embryology of avian specie have Investigated skeleton development of the indigenous Iraqi duck embryos. Data on the normal stages of skeleton chondrogenesis and osteogenesis and growth of all skeletal bony elements of the embryo in the duck are essential parameters to interpret and elucidate the data acquired on these studies. Fifty fertilized eggs of local breed ducks were collected from Kirkuk city villages, were incubated. As a mean of an egg daily used to prepare embryo every 24 hours from 7th through 28th day (last day) of incubation. After fixation of the embryos in absolute ethyl alcohol, they stained in a double staining of Alcian Blue and Alizarin Red stains for identification of both chondrofication of cartilage and ossification of bone elements respectively .The skeleton of macerated embryos were observed under stereoscopic microscope, giving special attention to the timing of both chondrofication and ossification of all bones. The onset of appearance of the primary ossification centre of each bone was chased serially. On 11thday of incubation the primary ossification centre observed firstly in the mid-diaphysis of the femur, tibia and fibula of the leg in addition to ossifying of the supraangular, quadratojugal of the skull followed by serial onset of ossification of other skeletal elements of the embryos.
The bones of the skull were determined to show the latest chondrofication and ossification. All elements of the hyoid apparatus were remained cartilaginous during hatching except the ceratobrancheal. Whereas the vertebral column showed chondrofication earlier than that of ribs and sternum, which ossified later. On the other hand chondrofication of all vertebral column elements were happened at the same time, and they ossified progressing from the cervical through the caudal region.
The bones of the leg showed chondrofication and ossification earlier than that of the wing. This phenomena seems to be normal because of the natural feature of the duck lets which attends to swimming after hatching