A comparative study on biological aspect of sperm in sterlet and Siberian sturgeon

sperm morphology, biochemistry and physiology were compared between siberian sturgeon Acipenser baerii and sterlet A. ruthenus in the present study. We observed wide morphological variations between spermatozoa of the two species. the average length of the spermatozoon head was 7.01 and 5.14 μm in A. baerii and A. ruthenus, respectively. Significant differences were observed in terms of Na+, k+ and clconcentrations in the seminal plasma as well sperm velocity. key words. sperm Morphology Physiology sterlet siberian sturgeon. Cybium 2008, 32(2) suppl.: 179-180. (1) University of south bohemia, Research institute of Fish culture and Hydrobiology, 389 25 vodnany, czech Republic. [psenicka@ vurh.jcu.cz] (2) UMR 7009 cnRs, UPMc, 06 230 villefranche-sur-Mer cedex, France. 3 centre of biology, institute of Parasitology, academy of sciences of the czech Republic, 370 05 ceske budejovice, czech Republic. Introduction sperm morphology, biochemistry and physiology were compared between siberian sturgeon A. baerii and sterlet A. ruthenus in the present study. Methods spermatozoa morphology was studied using scanning (seM) and transmission electron microscopy (teM) (Psenicka et al., 2007). osmolality, sperm density, pH, ionic composition of seminal plasma and sperm motility were measured (linhart et al., 2003). results and discussion sperm-cells possessed a head with an acrosome, a midpiece and a flagellum compacted of an axoneme (9 + 2) and a fin (Fig. 1A). The average diameters of Siberian sturgeon and sterlet spermatozoa are shown in table i. ten posterolateral projections in siberian sturgeon (600 nm length) and nine to ten in sterlet (550 nm length) were derived from the acrosome. the nucleus contained three endonuclear canals leading from the acrosome to the basal nuclear fossa region. There were three to six mitochondria, centriolar complex compacted of three peripheral microtubules in the midpiece. There was an extracellular cytoplasm canal separating the midpiece and the flagellum (Fig. 1B). Mean values of sperm density, seminal plasma pH, osmolality, along with calcium, sodium, potassium and chloride ion concentration are shown in table II. Significant differences were in sodium, potassium and chloride concentrations and sperm velocity, but not in motility (tab. iii). conclusion The present study revealed large interor intra-specific differences in terms of morphology, which is valuable taxonomically. in addition, the observed biochemical and physiological differences should be considered for development of artificial reproduction. Figure 1. sperm head of siberian sturgeon (A) (scale bar = 1 μm) and sterlet (b) (scale bar = 2 μm), with arrows pointing to the origin and the end of the fins along the flagellum. acrosome (a), nucleus (N), midpiece (MP), cytoplasmatic canal (CC), flagellum (F), nuclear fossa (NF), proximal centriole (PC), posterolateral projections (PP). Acknowledgements. The present study was supported financially by Usb RiFcH no. MsM6007665809 and GacR no. 524/06/0817. references Psenicka M., alavi s.M.H., Rodina M., Gela d., nebesaRova J. & o. linHaRt, 2007. Morphology and ultrastructure of siberian sturgeon, Acipenser baerii, spermatozoa using scanning and transmission electron microscopy. Biol. Cell., 99: 103-115. linHaRt o., MiMs s.d., GoMelskY b., Hiott a.e., sHelton W.l., cosson J., Rodina M., Gela d. & J. bastl, 2003. Ionic and osmolality of paddlefish (Polyodon spathula, acipenseriformes) seminal fluid with motility parameters. Aquacult. Int., 11: 357-368. Sterlet and Siberian sturgeon sperm Psenicka et al. 180 Cybium 2008, 32(2) suppl. table i. Morphological comparisons of sperm cells in sturgeon species (μm). al: acrosome length, aW: acrosome width, nl: nuclear length, nW: nucleus width (a-anterior, P-posterior), Ml: Midpiece length, MW: Midpiece width (a-anterior, P-posterior), Fl: Flagellum length. table ii. sperm density (109 spz ml-1), osmolality (mosmol kg-1) and ionic composition (mM) of the seminal plasma. table iii. comparison of sperm velocity (μm s-1) and motility (%) between siberian sturgeon and sterlet.