Histological Studies on the Sex Differentiation in Rainbow Trout

Takashima, Fumio; Patiño, Reynaldo; Nomura, Masatoshi

doi:10.2331/suisan.46.1317

Cited by 55 publications

(44 citation statements)

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“…These results agree with those of previous studies on rainbow trout in which sexual differentiation occurred at about 600 degree-days post-fertilization (Van den Hurk and Slof, 19811, 2 months after fertilization (Takashima et al, 1980) or shortly after completion of yolk sac resorption (Padoa, 19391. The number of germ cells in the present study was found to be higher in rainbow trout ovaries than in indifferent gonads. This observation has also been reported in O. keta (Robertson, 1953) and Salmo trutta (Ashby, 1957 Hardisty (1967).…”

Section: Introductionsupporting

confidence: 83%

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri) during the first 10 post-hatching weeks

Lebrun¹,

Billard²,

Jalabert³

et al. 1982

Reprod. Nutr. Dévelop.

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Summary. The number of germ cells in fry gonads was determined from histological sections sampled periodically over a 10-week post-hatching period. Several The number of germ cells increased regularly from 47 ± 35 (SD) after hatching (PGC) to 166 ± 25 at 2 post-hatching weeks (G!). At 5 post-hatching weeks, two groups of fish could be distinguished by the number of their germ cells (G 2 ) -one group had less than 926 cells and the other more than 1 577 ― and by their gonadal morphology (filiform or with an enlarged anterior part due to germ cell concentration). At 6 post-hatching weeks, the ovary differentiated with organization of the ovarian lamellae and the appearance of oocytes in meiotic prophase (4 out of 10 trout). The gonads of the other fish stayed at the indifferent stage. The number of germ cells was significantly higher in female-type gonads (6 335 ± 3 558) than in indifferent gonads (1 696 + 467). The situation was the same at 8 to 10 weeks.Introduction.

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Section: Introductionsupporting

confidence: 83%

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri) during the first 10 post-hatching weeks

Lebrun¹,

Billard²,

Jalabert³

et al. 1982

Reprod. Nutr. Dévelop.

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“…Serial sections were cut to 5µm and stained with Azocarmine B and Hubbs II (Humason 1972). Cross-sections were compared to photomicrographs from the salmonid literature (Takashima et al 1980, van den Hurk and Slof 1981, Nakamura 1982, Sacobie and Benfey 2005, Chiasson and Benfey 2007 and from the gadoid literature (Morrison 1990, Rommens 1997 to determine when gonadal differentiation occurred. The terminology of Patiño and Takashima (1995) is used to describe the cellular stages of differentiation.…”

Section: Methodsmentioning

confidence: 99%

Gonadal differentiation in Atlantic cod, <I>Gadus morhua</I> L., and haddock, <I>Melanogrammus aeglefinus</I> (L.)

Chiasson¹,

Benfey²,

Martin-Robichaud³

2008

Acta Icth et Piscat

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. 2008. Gonadal differentiation in Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.). Acta Ichthyol. Piscat. 38 (2): 127-133.Background. The purpose of this study was to determine the timing of gonadal differentiation in two gadoids: Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.). This information is required to develop a practical protocol for the production of monosex populations of these species for aquaculture. Materials and Methods. Cultured larvae and juveniles were collected weekly, measured (total length; TL), prepared histologically and then examined microscopically for the presence of characteristic stages of gonadal differentiation. Results. In Atlantic cod, undifferentiated gonads were present by 18 mm TL, at 84 days post hatch (dph), and definitive germ cells by 19 mm TL (90 dph). Ovarian cavities were first observed at 27 mm TL (102 dph), and by 35 mm TL (112 dph) anatomical divergence into two types of gonads was clear. In haddock, undifferentiated gonads were observed at 21 mm TL (64 dph) and an ovarian cavity was evident at 29 mm TL (71 dph). Conclusion. Gonadal differentiation in Atlantic cod and haddock occurs at roughly the same size in both species (27 and 29 mm TL, respectively). For successful sex reversal, the administration of steroids should therefore begin at approximately 25 mm TL, shortly after weaning onto dry feed.

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“…These time points were chosen because they represent initial testicular differentiation from the undifferentiated gonad with the presence of spermatogonia (18008d; Takashima et al 1980) and an actively meiotic, mid-spermatogenetic time point with spermatocytes and spermatids predominating the gonad prior to final sexual maturation (67008d; Kusakabe et al 2006) in rainbow trout. Degree day exposure times were calculated from 161 and 587 (dpf) using the rearing temperatures in our experimental holding facilities with individual animal weights of w10 and 750 g respectively.…”

Section: Exposure Trials and Sample Collectionsmentioning

confidence: 99%

Reduced embryonic survival in rainbow trout resulting from paternal exposure to the environmental estrogen 17α-ethynylestradiol during late sexual maturation

Brown¹,

Schultz²,

Nagler³

2007

Reproduction

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Exposure of fishes to environmental estrogens is known to affect sexual development and spawning, but little information exists regarding effects on gametes. This study evaluated embryonic survival of offspring from male rainbow trout (Oncorhynchus mykiss) exposed to 17a-ethynylestradiol (EE 2 ) using an in vitro fertilization protocol. Males were exposed at either 1800 or 6700 degree days (8d) (i.e. 161 or 587 days post-fertilization (dpf)) to test for effects on testes linked to reproductive ontogeny. At 18008d, fish were beginning testicular differentiation and were exposed to 109 ng EE 2 /l for 21 days. At 67008d, fish have testes containing spermatocytes and spermatids and were exposed for 56 days to either 0.8, 8.3, or 65 ng EE 2 /l. Semen was collected at full sexual maturity in each group and used to fertilize eggs pooled from several non-exposed females. Significant decreases in embryonic survival were observed only with the 67008d exposure. In 0.8 and 8.3 ng EE 2 /l treatments, embryo survival was significantly reduced at 19 dpf when compared with the control. In contrast, an immediate decrease in embryonic survival at 0.5 dpf was observed in the 65 ng EE 2 /l treatment. Blood samples collected at spawning from 67008d exposed males revealed a significant decrease in 11-ketotestosterone and a significant increase in luteinizing hormone levels for the 65 ng EE 2 /l treatment when compared with the other treatment groups. Results indicate that sexually maturing male rainbow trout are susceptible to EE 2 exposure with these fish exhibiting two possible mechanisms of reduced embryonic survival through sperm varying dependant on EE 2 exposure concentrations experienced.

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Histological Studies on the Sex Differentiation in Rainbow Trout

Cited by 55 publications

References 0 publications

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri) during the first 10 post-hatching weeks

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri) during the first 10 post-hatching weeks

Gonadal differentiation in Atlantic cod, <I>Gadus morhua</I> L., and haddock, <I>Melanogrammus aeglefinus</I> (L.)

Reduced embryonic survival in rainbow trout resulting from paternal exposure to the environmental estrogen 17α-ethynylestradiol during late sexual maturation

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