Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar)
Liver samples of two groups of juvenile Atlantic salmon (Salmo salar) were collected fall through spring and examined by light and transmission electron microscopy. One group of fish was maintained under simulated natural photoperiod (SNP), the other under an 8 month advanced, phase‐shifted photoper...
Published in: | Journal of Experimental Zoology |
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1991
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Online Access: | https://digitalcommons.uri.edu/favs_facpubs/143 https://doi.org/10.1002/jez.1402600202 |
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ftunivrhodeislan:oai:digitalcommons.uri.edu:favs_facpubs-1144 2023-07-30T04:02:24+02:00 Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) Robertson, John C. Bradley, Terence M. 1991-01-01T08:00:00Z https://digitalcommons.uri.edu/favs_facpubs/143 https://doi.org/10.1002/jez.1402600202 unknown DigitalCommons@URI https://digitalcommons.uri.edu/favs_facpubs/143 doi:10.1002/jez.1402600202 https://doi.org/10.1002/jez.1402600202 Fisheries, Animal and Veterinary Sciences Faculty Publications text 1991 ftunivrhodeislan https://doi.org/10.1002/jez.1402600202 2023-07-17T18:49:40Z Liver samples of two groups of juvenile Atlantic salmon (Salmo salar) were collected fall through spring and examined by light and transmission electron microscopy. One group of fish was maintained under simulated natural photoperiod (SNP), the other under an 8 month advanced, phase‐shifted photoperiod (8MA). As indicated by changes in branchial Na+/K+ATPase activity, salinity tolerance, and morphological characteristics, fish in the SNP group underwent parr‐smolt transformation in the spring. Smoltification‐associated changes in ultrastructure were observed in liver parenchymal cells only. Hepatocytes of SNP smolts were smaller with markedly decreased glycogen content as compared to cells of SNP parr. An increase in mitochondrial size and a decrease in numbers of mitochondria per hepatocyte were also seen during smoltification. In smolt hepatocytes, the nucleus and mitochondria occupied a greater percent of the cell volume than in parr liver parenchymal cells. Rough and smooth endoplasmic reticulum, dense bodies, and Golgi profiles also appeared to occupy more of the cell volume of smaller hepatocytes seen during smoltification. No smoltification‐associated changes were seen in hepatocyte nuclear size, chromatin state, or nucleolar frequency. During the fall, Atlantic salmon in the 8MA group underwent some morphological and osmoregulatory changes associated with smoltification. Hepatic fine structure of these fish in the fall resembled that seen in SNP smolts. In spring, 8MA fish exhibited no indications of smoltification, and hepatocyte ultrastructure of these fish was similar to that of SNP parr. Biological implications of observations are discussed, particularly in light of other investigations concerning the liver and smoltification. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company Text Atlantic salmon Salmo salar University of Rhode Island: DigitalCommons@URI Journal of Experimental Zoology 260 2 135 148 |
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University of Rhode Island: DigitalCommons@URI |
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ftunivrhodeislan |
language |
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description |
Liver samples of two groups of juvenile Atlantic salmon (Salmo salar) were collected fall through spring and examined by light and transmission electron microscopy. One group of fish was maintained under simulated natural photoperiod (SNP), the other under an 8 month advanced, phase‐shifted photoperiod (8MA). As indicated by changes in branchial Na+/K+ATPase activity, salinity tolerance, and morphological characteristics, fish in the SNP group underwent parr‐smolt transformation in the spring. Smoltification‐associated changes in ultrastructure were observed in liver parenchymal cells only. Hepatocytes of SNP smolts were smaller with markedly decreased glycogen content as compared to cells of SNP parr. An increase in mitochondrial size and a decrease in numbers of mitochondria per hepatocyte were also seen during smoltification. In smolt hepatocytes, the nucleus and mitochondria occupied a greater percent of the cell volume than in parr liver parenchymal cells. Rough and smooth endoplasmic reticulum, dense bodies, and Golgi profiles also appeared to occupy more of the cell volume of smaller hepatocytes seen during smoltification. No smoltification‐associated changes were seen in hepatocyte nuclear size, chromatin state, or nucleolar frequency. During the fall, Atlantic salmon in the 8MA group underwent some morphological and osmoregulatory changes associated with smoltification. Hepatic fine structure of these fish in the fall resembled that seen in SNP smolts. In spring, 8MA fish exhibited no indications of smoltification, and hepatocyte ultrastructure of these fish was similar to that of SNP parr. Biological implications of observations are discussed, particularly in light of other investigations concerning the liver and smoltification. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company |
format |
Text |
author |
Robertson, John C. Bradley, Terence M. |
spellingShingle |
Robertson, John C. Bradley, Terence M. Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
author_facet |
Robertson, John C. Bradley, Terence M. |
author_sort |
Robertson, John C. |
title |
Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
title_short |
Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
title_full |
Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
title_fullStr |
Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
title_full_unstemmed |
Hepatic ulstrastructure changes associated with the parr‐smolt transformation of Atlantic salmon (Salmo salar) |
title_sort |
hepatic ulstrastructure changes associated with the parr‐smolt transformation of atlantic salmon (salmo salar) |
publisher |
DigitalCommons@URI |
publishDate |
1991 |
url |
https://digitalcommons.uri.edu/favs_facpubs/143 https://doi.org/10.1002/jez.1402600202 |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_source |
Fisheries, Animal and Veterinary Sciences Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/favs_facpubs/143 doi:10.1002/jez.1402600202 https://doi.org/10.1002/jez.1402600202 |
op_doi |
https://doi.org/10.1002/jez.1402600202 |
container_title |
Journal of Experimental Zoology |
container_volume |
260 |
container_issue |
2 |
container_start_page |
135 |
op_container_end_page |
148 |
_version_ |
1772813185980563456 |