The severe decrease in natural sturgeon stocks has led to intensified efforts toward the development of sturgeon aquaculture and the application of reproductive biotechnologies to ensure sustainable production. In cultured male Acipenser ruthenus (sterlet), spermiation must be hormonally induced to obtain high-quality semen; however, reducing hormonal dosages while maintaining or improving sperm quality remains a major challenge. In this study, we investigated the effects of reduced doses of carp pituitary extract (CPE) and luteinizing hormone-releasing hormone agonist (LH-RH) combined with Apilarnil supplementation on spermiation and semen quality in A. ruthenus. Semen volume, pH, sperm concentration, total sperm output, total motility, and spermatozoa velocity were evaluated. Administering a reduced CPE dose (1.1 mg·kg⁻¹) combined with 1 g of Apilarnil significantly increased semen volume, sperm concentration, and total sperm output, as well as improved sperm kinematic parameters (total motility and velocity) compared with the conventional hormonal protocol. Furthermore, treatments using 50% of the standard LH-RH dose supplemented with 1 g or 2 g of Apilarnil resulted in significantly higher sperm motility and velocity than observed in the control group. These results demonstrate that Apilarnil supplementation allows for a substantial reduction in exogenous hormonal doses while enhancing spermiation efficiency and semen quality in sterlet, supporting the spermiation-induction protocol for sturgeon aquaculture.

The present study investigates the role of royal jelly as a natural endocrine modulator of serum estradiol levels in juvenile sterlets (Acipenser ruthenus), a species of major interest for sustainable aquaculture. The experiment was conducted over a period of 85 days under controlled recirculating system conditions, using four dietary treatments (n = 30 fish per group): a control group and three groups supplemented with 1%, 3%, and 5% royal jelly. Serum estradiol concentrations were determined by high-performance liquid chromatography (HPLC), while biometric assessment included the determination of total length (L), standard length (Sl), maximum body height (H), body circumference (C), and body mass (BM). Royal jelly supplementation significantly increased serum estradiol levels in a dose-dependent manner (p < 0.05), with the highest values recorded in the 5% group compared to the control. The proportion of individuals with non-detectable estradiol levels decreased progressively with increasing supplementation level. Biometric analysis revealed moderate effects on growth parameters, with no statistically significant differences among groups for most traits (p > 0.05), except for maximum body height, which showed a significant overall effect (ANOVA, p = 0.0089). Principal Component Analysis (PCA) highlighted the relative independence between endocrine variability and growth dynamics. Overall, the findings support the potential of royal jelly as a natural endocrine modulator of serum estradiol, representing a promising and environmentally friendly alternative to synthetic hormonal substances used in aquaculture. This approach may contribute to the development of innovative nutritional strategies for endocrine control and the optimization of biological performance in sturgeons, in accordance with the principles of sustainable aquaculture.

The present study investigates the efficacy of propolis as a natural therapeutic agent in the wound healing process following minimally invasive surgical sex determination in sterlet sturgeon (Acipenser ruthenus) specimens. The experiment was conducted under controlled conditions using 40 specimens randomly allocated into four experimental groups (n = 10 per group): one control group and three groups treated topically with different propolis formulations (propolis tincture, Larix propolis cream, and CETA propolis cream). The progression of the healing process was evaluated using a clinical erythema scoring system at successive time points over a one-month period. The results indicated a reduction in erythema in the treated groups compared to the control group, suggesting potential anti-inflammatory and wound-healing-related effects of propolis. Among the tested treatments, the CETA propolis cream showed the most favorable descriptive healing trend. The findings suggest that propolis may represent a promising natural approach for the management of postoperative lesions in sturgeons, although further studies are needed to confirm these results and to elucidate the underlying mechanisms. However, further histological, microbiological, and compositional analyses are required to confirm these preliminary observations and clarify the underlying mechanisms.