Lysozyme Turnover during the Development of Chicken Oocyte

Lysozyme, the major oocyte enzyme was studied using the lysoplate assay, the turbidimetric assay, SDS-PAGE assay and native gel electrophoresis coupled with activity gel overlay system. Using the lysoplate assay, lysozyme activity was shown to exist in all developmental stages of oocytes although to various degrees. Both eggwhite and yolk, had lysozyme activity. Using the less sensitive quantitative turbidimetric lytic assay, lysozyme activity started to appear in the yolk fractions collected from the caudal region of the infundibulum. For the egg white, lysozyme activity started to appear in samples collected from the anterior portion of the magnum. It increased sharply when the ovum was found in the posterior portion of the magnum. Using the SDS-PAGE, a lysozyme band was not detectable in all the follicular stages of oogenesis. A very faint band of lysozyme was detected in all the yolk fractions collected from the different segments of the oviduct. For the egg white lysozyme started to appear in the fractions collected from the anterior portion of the magnum; this continued in all fractions until egg maturation. In native gel electrophoresis, coupled with the activity gel overlay, a distinct lysozyme activity band appeared in all fractions including egg yolk and egg white collected during the process of oogenesis .To our knowledge, this is the first report of the existence of lysozyme in both egg white and yolk, in all the developmental stages of the oocyte