Spawning induction in Sterlet sturgeon (Acipenser ruthenus) with recombinant GnRH: Analysis of hormone profiles and spawning indices

• Published in: Aquaculture 2021-02, Vol.533, p.736108, Article 736108
• Main Authors: Mohammadzadeh, Sedigheh, Yeganeh, Sakineh, Moradian, Fatemeh, Milla, Sylvain, Falahatkar, Bahram
• Format: Article
• Language: English
• Subjects: Acipenser ruthenus; Life Sciences; Ovulation; Recombinant GnRH; Reproductive Biology; Sex steroids; Sexual reproduction; Spawning
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2020.736108

In the present study, the biological function of recombinant gonadotropin-releasing hormone associate peptide (rGnRH) was tested for the induction of ovulation and spawning in Sterlet sturgeon (Acipenser ruthenus) broodstock. For this purpose, Sterlet sturgeon broodstock were divided into four treatments and treated with following preparing procedure: 0.9% NaCl (C); 2.5 μg kg body weight−1 (BW) LHRH-A2 (luteinizing hormone-releasing hormone-A2, L2.5); 2.5 μg kg BW−1 rGnRH (rGn2.5); 10 μg kg BW−1 rGnRH (rGn10). The capability of the rGnRH for eliciting biological response was studied in vivo by evaluating the changes of 17β estradiol (E2), progesterone (P) and testosterone (T) and by its ability for inducing final maturation. Blood samples were collected at the time of first injection, 10 h after the first injection and at ovulation time. The L2.5 or rGn10 treatments led to significantly lower E2 concentration 10 h after the first injection and at ovulation time compared to the baseline measures. E2 levels increased in the rGn2.5 treatment 10 h after the first injection and by ovulation time compared to the time of first injection. T levels were significantly increased in the L2.5 or rGn10 treatments 10 h after the first injection compared to the time of first injection and it further decreased at ovulation time. No significant differences were found in C and rGn2.5 treatments between the different sampling times. P secretion was significantly higher in the rGn10 or L2.5 treatments compared to C and rGn2.5 treatments 10 h after the first injection and at ovulation time. No significant difference was found in P secretion in the C and rGn2.5 treatments at different sampling times. The results showed that the rGnRH at the highest dose (10 μg kg BW−1) was more efficient than the other treatments in the induction of spawning and this dose caused P secretion and spawning in vivo. Our results present the possibility of using rGnRH in artificial reproduction of sturgeons and it can be introduced as a specific homologue to treat reproductive disorders in fish. •rGnRH had a positive effect in final maturation in Sterlet sturgeon.•rGnRH at the dose of 10 μg kg body weight−1 was efficient in spawning induction.•rGnRH can stimulate the secretion of sex-steroids in vivo.•rGnRH can be used as a specific homologue to treat reproductive disorders in fish.