title: In vivo induction of human chorionic gonadotropin by osmotic pump advances sexual maturation during pre-spawning phase in adult catfish.
abstract: Gonadal maturation is a critical event wherein gonads, under the influence of several hormones and factors, undergo cyclic morphological and physiological changes to produce functional gametes during the spawning phase. However, artificial induction can be effectively used to advance the maturation of gonad vis-à-vis spawning like behavior in seasonal breeders during the off-breeding season. In the present study, osmotic pumps loaded with 5000IU of human chorionic gonadotropin (hCG) or saline as control were implanted intraperitoneally for 21days during the pre-spawning phase (May-June) in catfish Clarias batrachus and C. gariepinus. Significant increase in gonado-somatic index and sperm motility, and in the levels of certain sex steroids were observed in the hCG treated catfish when compared to control while estradiol-17β (E2) was low. Histological analysis in hCG treated testis revealed densely packed sperm and/or spermatids inside the lumen wherein the control testis displayed normal characteristics of the pre-spawning phase. In females, histological analysis showed a significant increase in post-vitellogenic full-grown immature follicles as seen in the spawning phase. In accordance with this, the steroid hormone profile correlated well with steroidogenic shift from E2to 17α,20β-DP indicating oocyte maturation. However, in the control ovaries of C. batrachus, perinucleolar and pre-vitellogenic oocytes were seen to be predominant. In addition, when compared with the control, the hCG treated group displayed a significant increase in the transcripts of several genes associated with gonadal growth. Taken together, artificial induction by slow release of hCG is an effective strategy to advance sexual maturation in catfish in a programmed manner.
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, Telangana, India.
authors.forename: Raju
authors.initials: R
authors.lastname: Murugananthkumar
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, Telangana, India.
authors.forename: Yarikipati
authors.initials: Y
authors.lastname: Prathibha
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, Telangana, India. Electronic address: bsksl@uohyd.ernet.in.
authors.forename: Balasubramanian
authors.initials: B
authors.lastname: Senthilkumaran
authors.affiliation: Department of Animal Biology, School of Life Sciences, University of Hyderabad, P.O. Central University, Hyderabad 500046, Telangana, India.
authors.forename: Anbazhagan
authors.initials: A
authors.lastname: Rajakumar
authors.affiliation: Department of Marine Biology and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kagawa
mesh_terms: D000818:Animals; D002397:Catfishes / Q000097:blood / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D012739:Gonadal Steroid Hormones / Q000097:blood / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D009866:Oogenesis / Q000187:drug effects; D009995:Osmosis; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D012741:Sexual Maturation / Q000187:drug effects*; D012965:Sodium Chloride / Q000494:pharmacology; D013081:Sperm Motility / Q000187:drug effects; D013737:Testis / Q000187:drug effects / Q000378:metabolism; D013739:Testosterone / Q000097:blood; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D006063:Chorionic Gonadotropin; D012739:Gonadal Steroid Hormones; D014157:Transcription Factors; D013739:Testosterone; D012965:Sodium Chloride; D004958:Estradiol
keywords: Final oocyte maturation; Osmotic pump; Pre-spawning; Spermatogenesis; Steroidogenesis; hCG induction