Comparative effects of human chorionic gonadotropin (hCG) and Ovaprim™ (sGnRHa + domperidone) on the reproductive characteristics of wild-caught male Longspine scraper, Capoeta trutta (Heckel, 1843)

• Ovaprim™ treatment effectively stimulated steroidogenesis and spermiation in male C. trutta.
• Hormonal treatments altered seminal plasma compositions in male C. trutta.
• hCG treatment exert very weak effect on spermiation induction in male C. trutta.

The effectiveness of two different hormonal treatments or a saline control on sperm characteristics, plasma sex steroids and testes histology of male Longspine scraper, Capoeta trutta (Heckel, 1843) collected from the wild and maintained in captivity were tested. Fish injected with Ovaprim™ had significantly increased gonadosomatic index (GSI) and sperm volume, but had decreased spermatozoa concentration and spermatocrit compared with control. Fish injected with hCG had significantly decreased motility duration of their sperm, as well as decreased spermatozoa concentration and spermatocrit. Both treatments increased seminal plasma pH compared with control, while decreases in osmolality of seminal plasma occurred only in Ovaprim™-treated fish.Hormonal treatments altered the seminal plasma sodium (Na+), calcium (Ca2 +), magnesium (Mg2 +), glucose, phosphorus, urea, creatinine, alanine aminotransferase (ALT), and alkaline phosphatase (ALP) concentrations. However, neither treatment affected the seminal plasma potassium (K+), chloride (Cl−), uric acid, total protein, cholesterol, triglycerides, and aspartate aminotransferase (AST) concentrations.The concentration of 17,20β-dihydroxy-4-pregnen-3-one (DHP) in the plasma was significantly enhanced by Ovaprim™ treatment, but not by hCG. On the other hand, plasma testosterone (T) was significantly elevated by both treatments.Histological examination of the testes revealed stimulation of testicular maturation following treatment with Ovaprim™, with lobules observed that were filled exclusively with a large number of spermatozoa (spz). In summary, hormonal treatments stimulated steroidogenesis and spermiation in male C. trutta, with highest efficiency of the Ovaprim™ treatment. Therefore, it can be concluded that like many other cyprinids, dopamine inhibitory action was operating in C. trutta, thus requiring anti-dopaminergic and hormonal treatments to overcome this in order to maximize steroidogenesis and induction of spermiation.Statement of relevanceThe research I present in this paper is novel, as:
• The effectiveness of exogenous hormones on male C. trutta reproduction under controlled conditions;
• The effect of hormonal treatment on a wide range of seminal plasma compositions in C. trutta;
• Valuable information which will assist commercial facilities in organizing and, spermiation success in this new aquaculture species.