Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory
As for other teleosts, the level of primary oocyte production ultimately determines the number of eggs shed by Atlantic cod Gadus morhua, but so far these minute cells have been little studied, probably due to methodological challenges. We established a quantitative “grid method” based on simple ooc...
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American Fisheries Society
2011
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ftbioone:10.1080/19425120.2011.555714 2024-06-02T08:03:07+00:00 Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory Olav S. Kjesbu Anders Thorsen Merete Fonn Olav S. Kjesbu Anders Thorsen Merete Fonn world 2011-01-01 text/HTML https://doi.org/10.1080/19425120.2011.555714 en eng American Fisheries Society doi:10.1080/19425120.2011.555714 All rights reserved. https://doi.org/10.1080/19425120.2011.555714 Text 2011 ftbioone https://doi.org/10.1080/19425120.2011.555714 2024-05-07T00:51:43Z As for other teleosts, the level of primary oocyte production ultimately determines the number of eggs shed by Atlantic cod Gadus morhua, but so far these minute cells have been little studied, probably due to methodological challenges. We established a quantitative “grid method” based on simple oocyte packing density (OPD) theory, accurate input data on ovary volume, oocyte-stage-specific ovarian volume fractions (from hits on grid-overlaid sections), and individual oocyte volumes (from diameter measurements of transections). The histological OPD results were successfully validated by automated measurements in whole mounts. The analyzed material originated from cultured Atlantic cod held in tanks for 19 months through the first maturity cycle and part of the second maturity cycle. Prior to sexual maturity, none of the fish showed the so-called circumnuclear ring (CNR; rich in RNA and organelles) in the cytoplasm of their primary oocytes, but this ring (phases 4a, 4b, and 4c) quickly appeared later on around the time of the autumnal equinox, followed by production of cortical alveolar oocytes (CAOs), early vitellogenic oocytes (EVOs), and late vitellogenic oocytes (LVOs). A very similar pattern was observed in the second maturity cycle. Thus, it is concluded that an autumnal night longer than 12 h generally triggers oocyte growth in Atlantic cod. A few immature individuals became arrested at the early CNR phase (phase 4a); hence, the use of CNR presence as a maturity marker should be treated with some caution. The maximum OPD was 250,000 oocytes/g of ovary for phase 4a; 100,000 oocytes/g for combined phases 4b and 4c; 100,000 oocytes/g for CAOs; 50,000 oocytes/g for EVOs; and 25,000 oocytes/g for LVOs. The relative somatic fecundity showed a dome-shaped curve with oocyte development (from CAO to LVO). Production of CAOs appeared at a fresh oocyte diameter of 180 µm, which is significantly below the commonly accepted threshold value of 250 µm for developing Atlantic cod oocytes. Text atlantic cod Gadus morhua BioOne Online Journals Marine and Coastal Fisheries 3 1 92 105 |
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English |
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As for other teleosts, the level of primary oocyte production ultimately determines the number of eggs shed by Atlantic cod Gadus morhua, but so far these minute cells have been little studied, probably due to methodological challenges. We established a quantitative “grid method” based on simple oocyte packing density (OPD) theory, accurate input data on ovary volume, oocyte-stage-specific ovarian volume fractions (from hits on grid-overlaid sections), and individual oocyte volumes (from diameter measurements of transections). The histological OPD results were successfully validated by automated measurements in whole mounts. The analyzed material originated from cultured Atlantic cod held in tanks for 19 months through the first maturity cycle and part of the second maturity cycle. Prior to sexual maturity, none of the fish showed the so-called circumnuclear ring (CNR; rich in RNA and organelles) in the cytoplasm of their primary oocytes, but this ring (phases 4a, 4b, and 4c) quickly appeared later on around the time of the autumnal equinox, followed by production of cortical alveolar oocytes (CAOs), early vitellogenic oocytes (EVOs), and late vitellogenic oocytes (LVOs). A very similar pattern was observed in the second maturity cycle. Thus, it is concluded that an autumnal night longer than 12 h generally triggers oocyte growth in Atlantic cod. A few immature individuals became arrested at the early CNR phase (phase 4a); hence, the use of CNR presence as a maturity marker should be treated with some caution. The maximum OPD was 250,000 oocytes/g of ovary for phase 4a; 100,000 oocytes/g for combined phases 4b and 4c; 100,000 oocytes/g for CAOs; 50,000 oocytes/g for EVOs; and 25,000 oocytes/g for LVOs. The relative somatic fecundity showed a dome-shaped curve with oocyte development (from CAO to LVO). Production of CAOs appeared at a fresh oocyte diameter of 180 µm, which is significantly below the commonly accepted threshold value of 250 µm for developing Atlantic cod oocytes. |
author2 |
Olav S. Kjesbu Anders Thorsen Merete Fonn |
format |
Text |
author |
Olav S. Kjesbu Anders Thorsen Merete Fonn |
spellingShingle |
Olav S. Kjesbu Anders Thorsen Merete Fonn Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
author_facet |
Olav S. Kjesbu Anders Thorsen Merete Fonn |
author_sort |
Olav S. Kjesbu |
title |
Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
title_short |
Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
title_full |
Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
title_fullStr |
Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
title_full_unstemmed |
Quantification of Primary and Secondary Oocyte Production in Atlantic Cod by Simple Oocyte Packing Density Theory |
title_sort |
quantification of primary and secondary oocyte production in atlantic cod by simple oocyte packing density theory |
publisher |
American Fisheries Society |
publishDate |
2011 |
url |
https://doi.org/10.1080/19425120.2011.555714 |
op_coverage |
world |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_source |
https://doi.org/10.1080/19425120.2011.555714 |
op_relation |
doi:10.1080/19425120.2011.555714 |
op_rights |
All rights reserved. |
op_doi |
https://doi.org/10.1080/19425120.2011.555714 |
container_title |
Marine and Coastal Fisheries |
container_volume |
3 |
container_issue |
1 |
container_start_page |
92 |
op_container_end_page |
105 |
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1800747594265133056 |