MODULATION OF GONADAL STEROIDS PRODUCTION BY TILAPIA PITUITARY EXTRACT: AN EVALUATION THROUGH IN-VITRO AND IN-VIVO STUDIES
Keywords:
Cichlids, Tilapia pituitary, Estradiol, VitellogeninAbstract
Objective: Endocrine regulation strategies are widely used for synchronization of fertility, but in some cichlids species, the treatments are not always effective. This study used tilapia (Oreochromis niloticus) as a model cichlid fish to evaluate homologous pituitary extract in-vitro and in-vivo bioassays.
Methods: In this study, guinea pig Leydig cells, tilapia follicular cells, and female tilapia were treated with tilapia pituitary extract (TP) to evaluate the ability of TP to modulate steroid production in-vitro and in-vivo. Sex steroid hormone quantification was performed using enzyme immunoassay (ELISA), and the relative vitellogenin (Vtg) level was measured using Western blot during the maturation cycle of female fish.
Results: Treatment with TP in-vitro significantly increased testosterone and estradiol (E2) levels in guinea pig Leydig cells and in tilapia follicular cells, respectively. In-vivo experiments showed a significant increase in plasma E2 and Vtg concentration in the TP-treated female. Interestingly, 40% oocyte maturation was observed in TP-treated adult female tilapia whereas, only 7% was observed in the control group. TP treatment is increased relative fecundity significantly, reaching a production of 15.7±5.8 oocytes/g of female.
Conclusion: The outcome of this study suggests that TP has a potential use in the control of cichlid fish reproduction and can be used as an alternative method for fish fry production.
Â
Downloads
References
Shelton WL. Regulated sex control in commercially important fishes-A physiological perspective, Israel. J Aquac Bamid 2006;58:351-65.
Carrillo M. La Reproducción de los peces: aspectos básicos y sus aplicaciones en acuicultura.1ra Ed. Madrid: Fundación Observatorio Español para la Acuicultura; 2009.
Bonnet E, Fostier A, Bobe J. Microarray-based analysis of fish egg quality after natural or controlled ovulation. BMC Genomics 2007;8:55-63.
Levavi Sivan B, Borged J, Mañanos E, Gómez A, Lareyre J. Perspectives on fish gonadotropins and their receptors. Gen Comp Endocrinol 2010;165:412-37.
Levavi Sivan B, Biran J, Fireman E. Sex steroids are involved in the regulation of gonadotropin-releasing hormone and dopamine D2 receptors in female tilapia pituitary. Biol Reprod 2006;75:642-50.
Valladares L, Ronco A, Pino A. RNA synthesis in the Leydig cells during sexual maturation in the rat: Effect of the LH. J Endocrinol 1986;110:551-6.
Aizen J, Kasuto H, Matan G, Zakay H, Levavi Sivan B. Tilapia follicle-stimulating hormone (FSH): immunochemistry, stimulation by the gonadotropin-releasing hormone, and effect of biologically active recombinant FSH on steroid secretion. Biol Reprod 2007;76:692–700.
Ko H, Park W, Kim D, Kobayashi M, Sohn Y. Biological activities of recombinant Manchurian trout FSH and LH: their receptor specificity, steroidogenic and vitellogenic potencies. J Mol Endocrinol 2007;38:99-111.
Kazeto Y, Kohara M, Miura T, Miura Ch, Yamaguchi S, Trant J, et al. Japanese eel follicle-stimulating hormone (FSH) and luteinizing hormone (LH): Production of biologically active recombinant fish and LH by drosophila S2 cells and their differential actions on the reproductive biology. Biol Reprod 2008;79:938-46.
Shi GQ, Shao J, Jiang GB, Wang QX, Lu YQ, Liu JF, et al. Membrane chromatographic method for the rapid purification of vitellogenin from fish plasma. J Chromatogr B 2003;785:361-8.
Swart JC, Pool EJ. The development and validation of a quantitative ELISA for in vivo and in-vitro synthesized vitellogenin from Mossambicus tilapia (Oreochromis mossambicus). J Immunoassay Immunochem 2009;30:208-23.
Kagawa H, Fujie N, Imaizumi H, Masuda Y, Oda K, Adachi J, et al. Using osmotic pumps to deliver hormones to induce sexual maturation of female Japanese eels, Anguilla Japónica. Aquaculture 2013;388-391:30-4.
Ridha MT, Cruz EM. Effect of light intensity and photoperiod on the Nile tilapia Oreochromis niloticus (L.) seed production. Aquac Res 2000;31:609-17.
El-Sayed A-FM, Kawanna M. Effects of photoperiod on growth and spawning efficiency of Nile tilapia (Oreochromis niloticus L.) broodstock in a recycling system. Aquac Res 2007;38:1242-7.
Nagahama Y, Yamashita M. Regulation of oocyte maturation in fish. Dev Growth Differ 2008;50:195-19.