title: Gonadogenesis and slow proliferation of germ cells in juveniles of cultured yellowfin tuna, Thunnus albacares.
abstract: To develop techniques for seedling production of yellowfin tuna, the behavior of primordial germ cells (PGCs) and gonadogenesis were examined at 1-30 days post hatching (dph) using morphometric analysis, histological examination, and in situ hybridization. Immediately after hatching, PGCs were located on the dorsal side of the posterior end of the rectum under the peritoneum of the larvae, and at 3 dph they came into contact with stromal cells. PGCs and stromal cells gradually moved forward from the anus prior to 5 dph. At 7-10 dph, germ cells were surrounded by stromal cells and the gonadal primordia were formed. In individuals collected at 12 dph, PGCs were detected by in situ hybridization using a vasa mRNA probe that is a germ-cell-specific detection marker. The proliferation of germ cells in the gonadal primordia began at 7-10 dph. We observed double the number of germ cells at 30 dph (22 ± 3.2 cells), compared to that at 1 dph (11 ± 2.1 cells). Therefore, based on our data and previous reports, the initial germ cell proliferation of yellowfin tuna is relatively slower than that of other fish species.
authors.affiliation: Laboratory for Aquatic Biology, Faculty of Agriculture, Kinki University, Japan. Electronic address: kobayasi@nara.kindai.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Fisheries Laboratory of Kinki University, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Honryo
authors.affiliation: Fisheries Laboratory of Kinki University, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Agawa
authors.affiliation: Fisheries Laboratory of Kinki University, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Sawada
authors.affiliation: Autoridad de los Recursos Acuáticos de Panamá (ARAP), Panama.
authors.forename: Ileana
authors.initials: I
authors.lastname: Tapia
authors.affiliation: Autoridad de los Recursos Acuáticos de Panamá (ARAP), Panama.
authors.forename: Karla A
authors.initials: KA
authors.lastname: Macìas
authors.affiliation: Autoridad de los Recursos Acuáticos de Panamá (ARAP), Panama.
authors.forename: Amado
authors.initials: A
authors.lastname: Cano
authors.affiliation: Inter American Tropical Tuna Commission (IATTC), Panama.
authors.forename: Vernon P
authors.initials: VP
authors.lastname: Scholey
authors.affiliation: Inter American Tropical Tuna Commission (IATTC), Panama.
authors.forename: Daniel
authors.initials: D
authors.lastname: Margulies
authors.affiliation: Laboratory for Aquatic Biology, Faculty of Agriculture, Kinki University, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yagishita
mesh_terms: D000818:Animals; D017756:Aquaculture; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D005260:Female; D017403:In Situ Hybridization / Q000662:veterinary; D008297:Male; D009866:Oogenesis; D010063:Ovum / Q000166:cytology* / Q000378:metabolism; D010176:Panama; D046468:Sexual Development; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism; D014413:Tuna / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism
chemical_list: D015415:Biomarkers
keywords: Gonadal primordium; Gonadogenesis; Primordial germ cell; Yellowfin tuna