Document Type : Research Paper
Authors
1
Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2
Assistant Professor of Fisheries Department, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
3
Associate Professor of Fisheries Department Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
4
3. Associate Professor of Fisheries Department Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
5
1. Associate Professor of Fisheries Department Ahvaz Branch, Islamic Azad University, Ahvaz, Iran 2. Aquaculture Research Center, Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
10.22124/japb.2024.27317.1537
Abstract
The study of reproductive activity control mechanisms in fishes, which makes it possible to regulate sexual periods, is of particular importance and is increasingly directed towards assisted reproduction technologies. In this study, 90 breeding female fish with an average weight of 3±0.41 kg were used and the effect of two doses of pituitary gland extract (3 and 5 mg/kg fish body weight) in two stages of injection (the first stage at zero time and the second stage 12 hours later), on spawning performance (gonadosomatic index, percentage of fertilization, hatching and survival), the level of sex steroids, the expression of genes related to steroidogenesis and tissue follicle growth (ZP2, Cyp191a1 and SF-1) and the histological changes of the ovary of female Rohu fish (Labeo rohita) were investigated. This study showed that the highest spawning success was observed with a pituitary dose of 5 mg/kg, and the incubation period of the female decreased with increasing dose. In addition, the fertility of this treatment was significantly higher than other groups. Treatment with pituitary gland extract in both doses caused a significant increase in gonadosomatic index, percentage of fertilization, hatching and survival of larvae compared to the control and sham groups. At 12 hours after injection, pituitary treatments showed a significant increase in the levels of steroid hormones and the expression of Zp2, Cyp191a1 and SF-1 genes in the ovarian tissue compared to the control and control treatments. Microscopic examinations of general and specific staining and micrometry of ovarian tissue follicles showed a steroidogenic change in the presence of asynchronous ovaries in the studied fish species, in which oocyte maturation was induced by injection of pituitary gland extract, especially a dose of 5 mg/kg of it, it accelerates. As a result, the findings show that Rohu females did not ovulate without hormone injection, while broods treated with pituitary gland extract did ovulate and the extract of the pituitary gland has synergistic effects on brain and ovarian activity and hormonal factors due to its ability to induce spawning, and because of these reasons, it increases the fertility and survival of the larvae of the studied species.
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