Retracted: Gonad histology and serum 11‐KT profile during the annual reproductive cycle in sterlet sturgeon adult males, Acipenser ruthenus

Abstract

The aim of this study was to assess monthly testicular development in the cultured breeding stock of sterlet, Acipenser ruthenus, using histological and serum sex steroid changes. Testicular development in the adult male was examined monthly and showed four distinct phases including resting, pre-spawning, spawning and post-spawning. Also, seasonal changes of the testes were described according to its variations in gonadosomatic index (GSI) during different phases of testicular development. Using histology, we identified continuous spermatogenesis and asynchronous gonad development pattern in the testes of male sterlet, which shows that regulation of annual gonadal cycle is influenced by season. Results also showed variation in the GSI value and number of spermatogenic cells according to each season during annual cycle of gonad, as the highest value of GSI was recorded during spawning phase (spring; March-May). Hormonal profiles of 11-ketotestosterone (11-KT) showed peak, which indicated a seasonal pattern of gonadal development. The 11-KT concentration increased considerably during the spermatogenesis (pre-spawning phase) and remained quite high throughout the pre-spermiation period. In the final phase of testicular development (spawning phase), the 11-KT markedly dropped. This study undertook an examination of complete reproductive development in cultured sterlet sturgeon to provide a valuable guide for the future sterlet studies, and allows comparison of reproductive development between sturgeon species.

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

“…The latter compartment, or interlobular tissue, was composed of connective tissue containing Leydig cells, myoid cells, macrophages, fibroblasts, collagen fibers, blood vessels and nerve fibers. The developmental stage of the mature testes examined corresponded to the pre‐spawning phase of A. ruthenus (Golpour et al, ) and to the same phase, identified as the reproductive stage IV, in S. platorynchus (Wildhaber et al, ).…”

“…Species of Acipenseridae are considered differentiated gonochorists, but hermaphroditism has been reported in one wild individual of the white sturgeon, Acipenser transmontanus Richardson, 1836 (Acipenseriformes: Acipenseridae) (Chapman, Van Eenennaam, & Doroshov, ), in farmed and artificially reproduced sterlet sturgeon, A. ruthenus Linnaeus, 1758 (Acipenseriformes: Acipenseridae) (Williot et al, ) and in wild individuals of the shovelnose sturgeon, Scaphirhynchus platorynchus (Rafinesque, 1820) (Acipenseriformes: Acipenseridae) captured in polluted waters (Harshbarger, Coffey, & Young, ). Intersexuality, a condition in which the male gonad contains oogonia or oocytes and the female gonad contains spermatogonia and spermatocytes, has been reported in wild Atlantic sturgeon, A. oxyrhinchus Mitchill, 1815 (Acipenseriformes: Acipenseridae) (Van Eenennaam & Doroshov, ) and also in farmed Siberian sturgeon, A. baerii Brandt, 1869 (Acipenseriformes: Acipenseridae) (Rzepkowska, Ostaszewska, Gibala, & Roszko, ), Russian sturgeon, A. gueldenstaedtii Brandt & Ratzeburg, 1833 (Acipenseriformes: Acipenseridae) (Jackson et al, ; Rzepkowska et al, ) and A. ruthenus (Golpour et al, ). In sturgeons, gonad sex differentiation requires between 3 and 15 months from birth according to species, geography, and environmental conditions (Akhundov & Fedorov, ; Alavi, Rodina, Gela, & Lihart, ).…”

Using machine learning algorithms to analyse the scute structure and sex identification of sterlet Acipenser ruthenus (Acipenseridae)

“…However, sturgeons have no reliable external sexual characteristics, as previously described (Chebanov & Galich, ; Fopp‐Bayat, ). Currently, to determine sex, hormonal (Du et al, ; Mosyagina & Zelennikov, ; Wheeler, Novak, Wippelhauser, & Sulikowski, ), biochemical (Barulin, ; Yarmohammadi et al, ), histological methods (Golpour et al, ) and biopsy, laparoscopy (Falahatkar & Poursaeid, ; Webb, Eenennaam, Crossman, & Chapman, ), endoscopy (Munhofen, Jiménez, Peterson, Camus, Jiménez, Peterson, Camus, & Divers, ) are used. Above methods have difficulties with mass application in aquaculture and can have a high error (the first two methods) or can traumatize fish (the last four methods).…”

Elimination of primordial germ cells in sturgeon embryos by ultraviolet irradiation†

“…It can be used only in warmwater fish species (such as tilapia), where the proliferation of spermatogonia is initiated by increasing the temperature. However, in sturgeons the spermatogonia proliferation begins when the temperature decreases (in autumn) [10], thus making busulfan unsuitable for use on sturgeons. Furthermore, busulfan treatment is known to cause side effects in fish, and the efficiency of GSCs removal is not always perfect [11–13].…”