Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua)
Thesis (Ph.D.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references (leaves 159-183) Atlantic cod, Gadus morhua, is an important commercial fisheries species in many North Atlantic countries. Due to the recent decline in cod populations worldwide, Atlantic cod has...
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2009
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Online Access: | http://collections.mun.ca/cdm/ref/collection/theses4/id/48271 |
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ftmemorialunivdc:oai:collections.mun.ca:theses4/48271 |
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Open Polar |
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Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
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ftmemorialunivdc |
language |
English |
topic |
Altantic cod--Development--Endocrine aspects Atlantic cod--Food Atlantic cod--Growth |
spellingShingle |
Altantic cod--Development--Endocrine aspects Atlantic cod--Food Atlantic cod--Growth Xu, Meiyu. Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
topic_facet |
Altantic cod--Development--Endocrine aspects Atlantic cod--Food Atlantic cod--Growth |
description |
Thesis (Ph.D.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references (leaves 159-183) Atlantic cod, Gadus morhua, is an important commercial fisheries species in many North Atlantic countries. Due to the recent decline in cod populations worldwide, Atlantic cod has become an emerging species in aquaculture in Canada, in particular New Brunswick, and Newfoundland and Labrador. The well-developed resistance to long-term starvation also makes cod a good model for the study of growth- and appetite-related hormones under both short-and long-term nutritional changes. The endocrinal regulation of food intake and energy homeostasis involves a two-way communication of hormones existing in central nervous system and several peripheral organs. I aimed to identify and characterizing genes coding for two growth-related factors (PACAP and SS), as well as one central (OX) and two peripheral (ghrelin and GRP) appetite-related factors in Atlantic cod. Multiple alignments and phylogenetic analyses show that the amino acid sequences all 5 peptides appear relatively conserved among fish, at least among teleosts. The typical expression patterns reflect their functional regions and are highly similar to those of other teleosts reported so far, with high forebrain expression levels for brain peptides and high stomach expression levels for gut peptides. For all the peptides in the present study, an early appearance in development probably indicates a crucial role in development. The apparent differences of expression for PPSS 1, OX and NPY before and after first larval feeding suggest that growth and appetite in fish are already under strict endocrine regulation at very early stages of life. The different expression patterns displayed by PPSS 1 and PRP/PACAP during fasting and re-feeding indicate that they might have distinct functions in the regulation of feeding and metabolism of Atlantic cod. OX and NPY both display periprandial changes and appear to be more affected by re-feeding than a long fasting period, while an increase in CART expression was induced during long-term food deprivation. Ghrelin displayed periprandial changes in expression but was not affected by fasting, while GRP did not display periprandial changes but was affected by food ration. One month exposure to different photoperiods did not affect food intake, body length or growth condition factors in juvenile cod. No overall orexigenic or anorexigenic tendency is shown in juvenile cod, though hypothalamic expressions of both NPY, an appetite stimulator, and CART, a feeding inhibitor, increase in cod exposed to complete darkness compared to fish in constant light. QPCR showed no significant effects of photoperiod on the expression levels of gut ghrelin and GRP. In general, the interaction displayed in Atlantic cod between brain and gut peptites with appetite and nutritional status may help further understanding of the endocrinal control of appetite and the effects of environmental factors, such as photoperiods, in teleosts. |
author2 |
Memorial University of Newfoundland. Dept. of Biology |
format |
Thesis |
author |
Xu, Meiyu. |
author_facet |
Xu, Meiyu. |
author_sort |
Xu, Meiyu. |
title |
Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
title_short |
Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
title_full |
Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
title_fullStr |
Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
title_full_unstemmed |
Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) |
title_sort |
endocrine regulation of appetite and growth in atlantic cod (gadus morhua) |
publishDate |
2009 |
url |
http://collections.mun.ca/cdm/ref/collection/theses4/id/48271 |
geographic |
Newfoundland Canada |
geographic_facet |
Newfoundland Canada |
genre |
atlantic cod Gadus morhua Newfoundland studies North Atlantic University of Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland studies North Atlantic University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (23.09 MB) -- http://collections.mun.ca/PDFs/theses/Xu_Meiyu.pdf a3241927 http://collections.mun.ca/cdm/ref/collection/theses4/id/48271 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766357333466677248 |
spelling |
ftmemorialunivdc:oai:collections.mun.ca:theses4/48271 2023-05-15T15:26:51+02:00 Endocrine regulation of appetite and growth in Atlantic cod (Gadus morhua) Xu, Meiyu. Memorial University of Newfoundland. Dept. of Biology 2009 xi, 183 leaves : ill. Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses4/id/48271 Eng eng Electronic Theses and Dissertations (23.09 MB) -- http://collections.mun.ca/PDFs/theses/Xu_Meiyu.pdf a3241927 http://collections.mun.ca/cdm/ref/collection/theses4/id/48271 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Altantic cod--Development--Endocrine aspects Atlantic cod--Food Atlantic cod--Growth Text Electronic thesis or dissertation 2009 ftmemorialunivdc 2015-08-06T19:21:57Z Thesis (Ph.D.)--Memorial University of Newfoundland, 2009. Biology Includes bibliographical references (leaves 159-183) Atlantic cod, Gadus morhua, is an important commercial fisheries species in many North Atlantic countries. Due to the recent decline in cod populations worldwide, Atlantic cod has become an emerging species in aquaculture in Canada, in particular New Brunswick, and Newfoundland and Labrador. The well-developed resistance to long-term starvation also makes cod a good model for the study of growth- and appetite-related hormones under both short-and long-term nutritional changes. The endocrinal regulation of food intake and energy homeostasis involves a two-way communication of hormones existing in central nervous system and several peripheral organs. I aimed to identify and characterizing genes coding for two growth-related factors (PACAP and SS), as well as one central (OX) and two peripheral (ghrelin and GRP) appetite-related factors in Atlantic cod. Multiple alignments and phylogenetic analyses show that the amino acid sequences all 5 peptides appear relatively conserved among fish, at least among teleosts. The typical expression patterns reflect their functional regions and are highly similar to those of other teleosts reported so far, with high forebrain expression levels for brain peptides and high stomach expression levels for gut peptides. For all the peptides in the present study, an early appearance in development probably indicates a crucial role in development. The apparent differences of expression for PPSS 1, OX and NPY before and after first larval feeding suggest that growth and appetite in fish are already under strict endocrine regulation at very early stages of life. The different expression patterns displayed by PPSS 1 and PRP/PACAP during fasting and re-feeding indicate that they might have distinct functions in the regulation of feeding and metabolism of Atlantic cod. OX and NPY both display periprandial changes and appear to be more affected by re-feeding than a long fasting period, while an increase in CART expression was induced during long-term food deprivation. Ghrelin displayed periprandial changes in expression but was not affected by fasting, while GRP did not display periprandial changes but was affected by food ration. One month exposure to different photoperiods did not affect food intake, body length or growth condition factors in juvenile cod. No overall orexigenic or anorexigenic tendency is shown in juvenile cod, though hypothalamic expressions of both NPY, an appetite stimulator, and CART, a feeding inhibitor, increase in cod exposed to complete darkness compared to fish in constant light. QPCR showed no significant effects of photoperiod on the expression levels of gut ghrelin and GRP. In general, the interaction displayed in Atlantic cod between brain and gut peptites with appetite and nutritional status may help further understanding of the endocrinal control of appetite and the effects of environmental factors, such as photoperiods, in teleosts. Thesis atlantic cod Gadus morhua Newfoundland studies North Atlantic University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) Newfoundland Canada |