Morphology and fine structure of the Russian sturgeon, Acipenser gueldenstaedtii (Acipenseridae, Chondrostei) spermatozoa

Abstract

Summary Spermatozoa morphology and fine structure were studied in the Russian sturgeon, Acipenser gueldenstaedtii (Acipenseridae, Chondrostei) spermatozoon using scanning and transmission electron microscopy. The spermatozoon is composed of an elongated head (length: 6.84 ± 0.04 μm) with an acrosome (1.18 ± 0.01 μm length and 1.05 ± 0.01 μm width), a cylindrical midpiece (length: 1.64 ± 0.03 μm) and a flagellum (length: 49.42 ± 0.37 μm). Eleven to 12 postero‐lateral projections (length: 0.65 ± 0.02 μm) were observed at the posterior edge of the acrosome. Three endonuclear canals was observed from the acrosome to the implantation fossa. In the midpiece, 4–6 mitochondria were observed as well as (i) a proximal centriole close to the implantation fossa and (ii) a distal centriole at the base of the axoneme. The flagellum consisted of nine peripheral microtubules and a central pair surrounded by the plasma membrane, which was extended while developing a pair of lateral fins along it. Inter‐individual differences in morphological dimensions of spermatozoa were detected. Principal component analysis performed on morphological parameters revealed 74.08% of the variance for the first three components. The acrosome width, midpiece length and posterior width of midpiece were correlated with component 1, flagellar length and total length with component 2, and head length, anterior width of head, posterior width of head and anterior width of midpiece with component 3. Inter‐species comparisons in Acipenseridae showed differences in morphological dimensions of spermatozoa. In this context, acrosome, head and midpiece dimensions in the Russian sturgeon were similar to those of Shortnose sturgeon, white sturgeon and Persian sturgeon. Length of the flagellum and total length of spermatozoon in the Russian sturgeon showed similarity to those of Lake sturgeon and Persian sturgeon.

Comparative testicular structure and spermatogenesis in bony fishes

“…The acrosome is absent in the spermatozoa of most bony fishes, but it is found in the sturgeons (Acipenseridae, Chondrostei) as Acipenser persicus 27 and Acipenser gueldenstaedtii. 28 The structure and size of spermatozoa vary considerably in complexity among teleost species. Fish spermatozoa are classified according to the external or internal mode of fertilization into 2 forms, aquasperm and introsperm, respectively.…”

Effects of dietary lipid sources on growth performance, lipid metabolism and antioxidant status of juvenile Russian sturgeonAcipenser gueldenstaedtii

“…; Hatef et al . ). The aim of this study was to investigate the impact of lipid source on growth performance, lipid metabolism and antioxidant status in juvenile Russian sturgeon in an attempt to identify the appropriate dietary lipid source for diet formulation in sturgeon aquaculture.…”

“…However, the bottleneck for the development of sturgeon aquaculture is the poor understanding on the nutritional requirement for grow-out (Kynard et al 2002;Hurvitz et al 2007;Memis ß et al 2009). Particularly, the knowledge on lipid requirement of juvenile Russian sturgeon is limited (Birstein et al 2000;Hurvitz et al 2007;Balev et al 2011;Hatef et al 2012). The aim of this study was to investigate the impact of lipid source on growth performance, lipid metabolism and antioxidant status in juvenile Russian sturgeon in an attempt to identify the appropriate dietary lipid source for diet formulation in sturgeon aquaculture.…”

Ultrastructural investigations on spermatogenesis and spermatozoan morphology in the endangered Adriatic sturgeon, Acipenser naccarii (Chondrostei, Acipenseriformes)

“…The total length of the spermatozoan head (i.e., the length of acrosome with nucleus and midpiece; 9.30 ± 0.88 µm) is comparable to that of A. fulvescens (DiLauro et al, ), A. gueldenstaedtii (Hatef et al, 2012) and A. brevirostrum (DiLauro et al, ), amounting 9.10, 9.66, and 9.71 µm, respectively. Interspecific variations of spermatozoan size within the order Acipenseriformes are considered of phylogenetic relevance and could also be related to morphological structure of eggs (Debus, Winkler, & Billard, ; DiLauro et al, ; Hatef et al, , ). The length and width of the acrosome in A. naccarii are similar to those of A. stellatus (Ginsburg, 1977), A. baerii (Pšenička et al, ), A. gueldenstaedtii (Hatef et al, 2012), H. huso (Linhartova et al, ), and S. albus (DiLauro et al, 2001).…”