Ultrastructure study of vitellogenesis of experimentally recovered Fasciola gigantica

Abstract

The ultrastructure of experimentally recovered Fasciola gigantica shows that vitelline cells are grouped in vitelline follicles. Vitelline cells developed through a series of developmental stages. At stage I of vitelline cell development, the nucleo-cytoplasmic ratio is high and the cytoplasm has many elongated mitochondria. In the stage II, the cisternae of endoplasmic reticulum is appeared, the formation of shell protein globules is started and the cell increases in size, while the nucleo-cytoplasmic ratio decreases. At the final stage of development, stage III, the prominent structure is the domination of shell protein globules as the vitelline cell is fully matured and ready to deliver its shell protein globules to the fertilized eggs. This study is the first to show the fine structure of vitelline cells of F. gigantica recovered from experimentally infected mice. The present work opens the way for more studies on experimentally recovered digenean worms and also exploring strategies for fighting the diseases caused by these worms.