Thyroxin Levels In Early Developmental Stages Of Coho Salmon Oncorhynchus Kisutch
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Thyroid Hormones in Relation to Early Development and Triiodothyronine (T3) Treatment of Coho Salmon (Oncorhynchus Kisutch) Eggs at Water Hardening
Author | : Elizabeth Ella Mooney |
Publisher | : |
Total Pages | : 184 |
Release | : 1991 |
Genre | : Coho salmon |
ISBN | : |
Physiological Changes Associated with the Diadromous Migration of Salmonids
Author | : Helga Rachel Høgåsen |
Publisher | : NRC Research Press |
Total Pages | : 142 |
Release | : 1998 |
Genre | : Nature |
ISBN | : 9780660176376 |
This volume presents and discusses present knowledge concerning the diadromous migration of salmonids. It groups elements ranging from ecology to cell biology, to provide the reader background knowledge for critical understanding of published literature and for design of experiments.
Hormonal and Osmoregulatory Aspects of Smoltification in Coho Salmon, Oncorhynchus Kisutch
Author | : Jennifer Lee Specker |
Publisher | : |
Total Pages | : 210 |
Release | : 1980 |
Genre | : Coho salmon |
ISBN | : |
Coho salmon smolts (Oncorhynchus kisutch) were transported at low and high densities. (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted directly to seawater, half of the fish in each treatment were transported to tanks containing seawater and half to tanks containing freshwater. Plasma corticosteroids and glucose were elevated at unloading in all groups. Corticosteroids were still above the resting levels 24 h later, whereas glucose had returned to basal levels at this time. Potential smoltification indicators such as plasma thyroxin concentration and gill Na-K-ATPase activity were not affected by transportation. Increased corticosteroids were correlated to increased mortality in transported salmon compared to acclimated control fish when subjected to a bioassay of stress severe confinement. It is concluded that transportation induced stress in the fish regardless of hauling regimen, that increased corticosteroids may have potential as indicators of reduced performance capacity, that the greatest stress occurred during loading and the first few hours en route, and that transported coho salmon smolts seem to be equally fit for entry into freshwater or seawater. Hormones of the hypothalamic-pituitary system probably mediate the environmental changes and endogenous rhythms that regulate the timing and physiological alterations of smoltification. Because thyroid hyperactivity is a major endocrine component of smoltification, yearling coho salmon were injected with mammalian prolactin (PRL) and thyrotropin (TSH) to determine their effect on plasma thyroxin concentrations. The response of plasma thyroxin to TSH is similar from January through May in coho salmon, suggesting that the thyroid does not change in sensitivity to TSH. A dose of 0.04 to 0.07 I.U. TSH is the minimum dose sufficient to significantly increase plasma thyroxin concentration. PRL (1 to 9 I.U.) depressed plasma thyroxin levels in coho salmon parr, smolts, and post-smolts. Increased plasma thyroxin and gill Na-K-ATPase levels tentatively are considered indicative of smoltification, migratory readiness, and hence, seawater adaptability. In an experiment to consider a methodology which could be implemented at a culture facility to enhance the survival of ocean-going smolts and perhaps mitigate losses due to stunting, an abnormality of smoltification, coho salmon parr were maintained for 3 wk in water supplemented with sodium or calcium salts. Prolonged residence in sodium - supplemented freshwater increased plasma thyroxin levels and tended to elevate gill Na-K-ATPase activity. In contrast, acute exposure (24 h) to 75% seawater halved plasma thyroxin levels in coho salmon parr. Gradual acclimation to increased ambient salinity may accelerate changes in, or enhance, plasma thyroxin levels and gill Na-K-ATPase activity, and thus potentially improve the growth and survival of outmigrating smolts and reduce losses due to stunting. Plasma corticosteroid levels were determined during smoltification and in response to mammalian PRL and TSH. The interrenal tissue, which synthesizes corticosteroids, becomes hyperactive during smoltification. Exogenous PRL and TSH have no effect on plasma corticosteroid levels at any time during smoltification. Plasma corticosteroid levels increase eight-fold between early April and late May in coho salmon, concurrent with increasing gill Na-K-ATPase and seaward migration. Generally, plasma levels of thyroxin and corticosteroids are related inversely. Thyroxin levels are maximum in early April, with the onset of silvering, and corticosteroids are at minimal concentrations at this time. Thereafter, thyroxin levels decline and corticosteroids increase.
Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea
Author | : American Fisheries Society |
Publisher | : |
Total Pages | : 192 |
Release | : 1998 |
Genre | : Medical |
ISBN | : |
Hormones and Reproduction of Vertebrates, Volume 1
Author | : David Norris |
Publisher | : Academic Press |
Total Pages | : 297 |
Release | : 2011-05-04 |
Genre | : Technology & Engineering |
ISBN | : 0080962297 |
This series of volumes represents a comprehensive and integrated treatment of reproduction in vertebrates from fishes of all sorts through mammals. It is designed to provide a readable, coordinated description of reproductive basics in each group of vertebrates as well as an introduction to the latest trends in reproductive research and our understanding of reproductive events. Whereas each chapter and each volume is intended to stand alone as a review of that topic or vertebrate group, respectively, the volumes are prepared so as to provide a thorough topical treatment across the vertebrates. Terminology has been standardized across the volumes to reduce confusion where multiple names exist in the literature, and a comprehensive glossary of these terms and their alternative names is provided. A complete, essential and up to date reference for research scientists working on vertebrate hormones and reproduction - and on animlals as models in human reproductive research Covers the endocrinology, neuroendocrinology, physiology, behaviour and anatomy of vertebrate reproduction Structured coverage of the major themes for all five vertebrate groups allows a consistent treatment for all Special chapters elaborate on features specific to individual vertebrate groups and to comparative aspects, similarities and differences between them
Environmental Toxicology and Risk Assessment
Author | : Diane Susan Henshel |
Publisher | : ASTM International |
Total Pages | : 500 |
Release | : 1999 |
Genre | : Biochemical markers |
ISBN | : 0803126182 |
The Endocrinology of Growth, Development, and Metabolism in Vertebrates
Author | : Martin Schreibman |
Publisher | : Academic Press |
Total Pages | : 620 |
Release | : 2012-12-02 |
Genre | : Science |
ISBN | : 0323144403 |
The Endocrinology of Growth, Development, and Metabolism in Vertebrates provides an overview of vertebrate endocrinology. This book aims to strengthen the bridge between medical and comparative endocrinologists by addressing the benefits that they can derive from this association. Organized into five parts encompassing 24 chapters, this volume starts with a discussion on the structure and biological function of growth hormone (GH) and prolactin (PRL) family. This book then explains the extrinsic, genetic, and humoral factors that influence animal growth, particularly in poikilotherms. This text also elaborates the environmental conditions that affect the growth of poikilotherms, including food availability, temperature, and photoperiod. Other chapters discuss how somatotropin affects the growth development in homeotherms, such as livestock species. The reader is also introduced to the metabolic actions of GH, which can be described in terms of short-lived insulin-like effects. Endocrinologists, molecular endocrinologists, biologists, molecular biologists, biochemists, researchers, and physicians will find this book extremely useful.