Ziber balığında (Epinephelus costae) 17 α-metiltestosteron Kullanılarak Erkekleşmenin Öne Çekilmesi

Öz Bu çalışmada 17α-metiltestosteron (MT)'un protogenus hermafrodit Ziber (Epinephelus costae) türünde cinsiyet dönüşümü üzerine olan etkileri araştırılmıştır. Ziber bireylerine 5 mg/kg/ay (MT5) ve 10 mg/kg/ay (MT10) 17α- metiltestosteron olacak şekilde her 15 günde bir toplam 5 kez implant yapılmıştır. Her bir uygulama için beşer balık kullanılmıştır. Sekizinci haftadaki implantın ardından MT10 grubunda bulunan 2 bireyde ölüm gerçekleşmiştir. Ölen bu balıklar disekte edilmiş, oositlerin dejenerasyona uğradığı ve sperm kanallarının belirginleştiği gözlenmiştir. Son implantın ardından (10. hafta) MT5 grubundaki bir bireyde gonadlarda fenotipik erkekleşmenin gerçekleştiği belirlenmiştir. Histolojik kesitlerde bir adet histozoik parazit olan Philometra lateolabricis'in (Nematoda: Philometridae) varlığı gözlenmiştir. Cinsiyet değişimi sağlanmaya çalışılan bireylerde gametlerin normal gelişim gösterememesinin sebebinin bu parazitin olabileceği varsayılabilir.

Induction of sex-reversed males using 17 α-methlytestosterone in the gold blotch grouper (Epinephelus costae)

In this study, the effects of 17α-methyltestosterone (MT) for induction of sex reversal in protogynous hermafrodit goldblotch grouper (Epinephelus costae) was investigated. Goldblotch grouper were implanted with 5 mg (MT5) and 10 mg (MT10) 17α-methyltestosterone kg-1 month-1 body month weight five times with 15 days intervals. Five fish were implanted for each treatment. After week 8 post-implantation, 2 fish died in MT10 group. These two fish were dissected and MT10 oocytes were degenerated, and sperm channels of these two fish were observed. After last implantation (week 10 post-implantation), only one fish in MT5 treatment induced advanced stages of spermatogenesis. A philometrid nematode, Philometra lateolabracis (Nematoda: Philometridae) was observed in fish in MT5 treatment. It was assumed that this parasitic nematod inhibits the normal development of the gamates in sex reversed females.

Kaynakça

Bruslé S., Debas L., Fourcault B. ve Fuchs J. 1992. Ultrastructural study of sex inversion in a protogynous hermaphrodite Epinephelus micro- don Teleostei Serranidae Reprod., Nutr., Dev., 32: 393-406.

Bruslé, S., Debas L. ve Cauty C. 1989. Morphological and cytological aspects of sex inversion in a protogynous hermaphrodite, Epinephelus microdon (Teleostei, Serranidae) Advances In Tropical Aquaculture, Tahiti, French Polynesia Actes Colloq. IFREMER, Tahiti, French Polynesia.

Chao, T. M. ve Chow, M. 1990. Effect of methyltestosterone on gonadal development of Epinephelus tauvina (Forskal). Singapore J Prim Ind 18: 1-14.

Fang, Y.Q., Lin, Q. M., Qi, X. ve Hong, G. Y. 1992. Effects of 17a methyltestosterone on sex reversal in Epinephelus akaara. J Fish China 16: 172-174.

Froese, R. ve Pauly, D. 2015. "FishBase. World Wide Web electronic publication.". www.fishbase.org. (Erişim Tarihi: 10.04.2015).

Genc, E. 2002. The endoparasites and histopathologies found in some commercial teleosts in the Bay of Iskenderun. PhD Thesis, Department of Fisheries, Institute of Natural and Applied Sciences, Adana, Turkey. University of Cukurova. Genç, E. 2011. Diseases in wild and cultured fish in Turkey. in: Aquaculture in the Middle East and North Africa- Status and Research Needs, (Azad, I.S. and S. Al-Ablani, Eds.), Nova Science Publications, N.Y., USA. (Chapter 4). URL: https://www.novapublishers.com /catalog/pro- duct_info.php?products _id = 22355 (Erişim Tarihi: 05.03.2015)

Genç, E., Genc, M. A., Genc, E., Cengizler, I. ve Can, M. F. 2005. Seasonal Variation and Pathology Associated with Helminthes Infecting Two Serranids (Teleostei) of Iskenderun Bay (North- East Mediterranean Sea), Turkey. Turkish Journal of Fisheries and Aquatic Sciences (TrJFAS), 5: 29-33.

Genç, E., Genc, M. A. ve Aktaş, M. 2012. Long-Term Observation on Philometra lateolabracis (Nematoda) Infections in Ovaries of Goldblotch Grouper (Epinephelus costae Steindachner, 1878), Iskenderun Bay, Northeast Mediterranean Sea. Aqua 2012, Prague, Czech Republic Sep. 1- 5, 2012 (#645). https://www.was.org/WasMee- tings/meetings/ShowAbstract.aspx?Id=26511.

Genç, E. ve Keskin, E. 2013. Philometra lateolabracis Steindachner, 1878 (Nematoda: Philometridae) in Epinephelus costae (Osteichthyes, Serra- nidae): First Molecular Identification of the Histozoic Parasite from Iskenderun Bay, Northeast Mediterranean Sea. Aqua 2012, Prague, Czech Republic Sep. 1-5, 2012 (#695). https://www.was.org/WasMeetings/meetings/Sh owAbstract.aspx?Id=26561.

Johnson, A. K. ve Thomas, P. 1995. Seasonal changes in gonadal histology and sex steroid hormone levels in the protogynous hermaphrodite, Epinephelus morio. Proceedings of the Fifth International Symposium on the Reproductive Physiology of Fish, The University Of Texas At Austin, Fish Symposium 95, Austin, TX (USA), p. 234.

Johnson, A. K., Thomas, P., Wilson Jr. ve R. R. 1998. Seasonal cycles of gonadal development and plasma sex steroid levels in Epinephelus morio, a protogynous grouper in the eastern Gulf of Mexico. J. Fish Biol. 52: 502-518.

Lee, S. T., Lam, T. J. ve Tan, C. H. 2000. Corticosteroid biosynthesis in vitro by testes of the grouper (Epinephelus coioides) after 17alpha-methyltes- tosterone-induced sex inversion. J Exp. Zool 287: 453-457.

Lee, S. T. L., Kime, D. E., Chao, T. M., Lim, H. S., Chou, R., Lam, T. J. ve Tan, C. H. 1995. In vitro meta- bolism of testosterone by gonads of the grouper (Epinephelus tauvina) before and after sex inversion with 17-alphamethyltestosterone. Gen. Comp. Endocrinol. 99: 41-49.

Lee, Y. D. 1995. Sexual phenomenon of protogynous serranid fish. Exploit. Mar. Resour., 143-150.

Li, G. L., Liu, X. C. ve Lin, H. R. 2006. Effects of 17a- methyltestosterone on sex reversal in red-spotted grouper, Epinephelus akaara. J Fish China 30: 145-150.

Mackie, M. 2000. Reproductive biology of the halfmoon grouper, Epinephelus rivulatus, at Ningaloo Reef, Western Australia. Environ. Biol. Fishes 57: 363- 376.

Mandich, A.M.G.M.A. 1998. In vitro steroid secretion by ovarian follicles of the grouper Epinephelus marginatus. Trends in Comparative Endoc- rinology and Neurobiology: From Molecular to Integrative Biology, The New York Academy of Sciences, 15 May 1998. Ann. N. Y. Acad. Sci. 839: 586-588.

Moravec, F. ve Genc, E. 2004. Redescription of Three Philometra spp. (Nematoda: Philometridae) from the Gonads of Marine Perciform Fishes of Iskenderun Bay (North-East Mediterranean), Turkey. Acta Prasitologica., 49 (1): 31-40.

Peatpisut, T. ve Bart, A. N. 2010. Cryopreservation of sperm from natural and sex-reversed orange- spotted grouper (Epinephelus coioides). Aqua- culture Research 42: 22-30.

Ricker, W. E. 1958. Handbook of computations for biological statistics of fish populatins. Fish. Res. Board Can. Bull. 199-300p.

Tanaka, H., Hirose, K., Nogami, K., Hattori, K. ve Ishibashi, N. 1990a. Sexual maturation and sex reversal in red spotted grouper, Epinephelus akaara. Bull. Natl. Res. Inst. Aquacult. 17: 1-15.

Tanaka, H., Hirose, K., Nogami, K. Y., Hattori, K. ve Ishibashi, N. 1990b. Sexual maturation and sex reversal in red spotted grouper Epinephelus akaara. Bull. Natl. Res. Inst. Aquacult. 17: 1-16.

Tan-Fermin, J. D. 1992. Withdrawal of exogenous 17- alpha methyl-testosterone causes reversal of sex- inversed male grouper Epinephelus suillus (Bloch and Schneider). Philipp. Sci. 29: 33-39.

Tan-Fermin, J. D., Garcia, L.M.B. ve Castillo Jr. A. R. 1994. Induction of sex inversion in juvenile grouper, Epinephelus suillus, (Valenciennes) by injections of 17 alpha-methyltestosterone. Jpn. J. Ichthyol. 40: 413-420.

Kaynak Göster