[doi: 10.5505/2017ichc.PP-153]Structural and ultrastructural description of the ovarian wall in astacid crayfish, {Astacus leptodactylus}Ana Maria Petrescu1, Lucia Moldovan2, Otilia Zarnescu32Department of Cellular and Molecular Biology, National Institute of Research and Development for Biological Sciences, Bucharest, Romania 3Laboratory of Histology and Developmental Biology, Faculty of Biology, University of Bucharest, Bucharest, Romania Astacid crayfish reproductive cycle represents a current topic related to the basis of astaciculture. Astacid crayfishes have one reproductive cycle per year. The general structure of the ovary has a sac shape with three lobes, two anterior and one posterior, located dorsally to the hepatopancreas, common to all crayfish species. The ovarian wall is an important structure given the species characteristics, external fertilization and development. The purpose of this study is to identify significant correlations between structure and thickness of the ovarian wall during the reproductive cycle. Several crayfish females were collected monthly from related localities in the southern part of Romania, tributaries of the Danube, ponds and as well the Danube River. The whole body and ovarian weight were obtained. The samples were fixed in Bouin solution and 6 µm histological sections were obtained. The general structure of the ovary was described using the hematoxylin-eosin-alcian blue staining (pH 2.5) and light microscopy. For transmission electron microscopy small fragments of ovary were fixed in glutaraldehyde, stained with uranyl acetate and lead citrate. Ovarian wall thickness was assessed for each reproductive period, from three sections and from 3 random points. During the reproductive cycle we have identified four distinct stages: immature, maturing, mature and spent. Its continuous structure with the oviduct ensures the cohesion of the three lobes and the expulsion to the oviduct of the mature egg and further to the gonopores. The micrometric measurements revealed that the thickness of the ovarian wall decreased in a significant manner from the spent stage to the mature stage (P<0.0001). This structure, which is part of the somatic compartment of the ovary, includes two layers of spindle-shaped smooth-like muscle cells: an inner circular one and an outer longitudinal one, more rich in acidic mucopolyssacharides, haemocytes (abundancy variable with the reproductive stages), blood vessels and hemal sinuses. The ovarian wall is more thick close to the oviduct. The present study underlines the importance of the ovarian wall during each stage of oogenesis and oviposition and it completes previous studies on crayfishes and lobsters. |