1
|
Chen X, Mi J, Huang H, Wang J, Wu Y, Wu X, Zhang S. Ghrelin and ghrelin receptor (GHSR) in Chinese alligator, alligator sinensis: Molecular characterization, tissue distribution and mRNA expression changes during the active and hibernating periods. Gen Comp Endocrinol 2022; 327:114097. [PMID: 35853503 DOI: 10.1016/j.ygcen.2022.114097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 07/02/2022] [Accepted: 07/13/2022] [Indexed: 11/20/2022]
Abstract
The Chinese alligator (Alligator sinensis) is a freshwater crocodilian endemic to China. So far, the endocrine regulation of feeding and growth in Chinese alligator is poorly understood. In this study, the molecular structure and tissue expression profiles of ghrelin and its receptor GHSR in the Chinese alligator were characterized for the first time. The full-length cDNA of ghrelin was 1770 bp, including a 37 bp 5 '-UTR (untranslated region), a 435 bp ORF (open reading frame) and a 1298 bp 3 '-UTR. The ORF encodes a ghrelin precursor, which consists of 145 amino acid residues, including a signal peptide with 52 amino acid residues at the N-terminus, a mature peptide with 28 amino acid residues, and a possibly obestain at the C-terminus. The full-length cDNA of GHSR was 3961 bp, including a 5'-UTR of 375-bp, an ORF of 1059-bp and a 3' -UTR of 2527-bp. The ORF encodes a protein of 352 amino acid residues containing seven transmembrane domains, with multiple N glycosylation modification sites and conserved cysteine residue sites. The active core "GSSF" of Chinese alligator ghrelin was identical to that of mammals and birds, and the ghrelin binding site of GHSR was similar to that of mammals. The amino acid sequences of both ghrelin and GHSR share high identity with American alligator (Alligator mississippiensis) and birds. Ghrelin was highly expressed in cerebrum, mesencephalon, hypothalamus and multiple peripheral tissues, including lung, stomach and intestine, suggesting that it could play functions in paracrine and/or autocrine manners in addition to endocrine manner. GHSR expression level was higher in hypothalamus, epencephalon and medulla oblongata, and moderate in multiple peripheral tissues including lung, kindey, stomach and oviduct, implicating that ghrelin/GHSR system may participate in the regulation of energy balance, food intake, water and mineral balance, gastrointestinal motility, gastric acid secretion and reproduction. During hibernation, the expression of ghrelin and GHSR in the brain was significantly increased, while ghrelin was significantly decreased in heart, liver, lung, stomach, pancreas and ovary, and GHSR was significantly decreased in heart, liver, spleen, lung, kindey, stomach, ovary and oviduct. These temporal changes in ghrelin and GHSR expression could facilitate the physiological adaption to the hibernation of Chinese alligator. Our study could provide basic data for further studies on the regulation of feeding, physiological metabolism and reproduction of Chinese alligator, which could also be useful for the improvement of artificial breeding of this endangered species.
Collapse
Affiliation(s)
- Xianxian Chen
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Jicong Mi
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Hongbin Huang
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Jing Wang
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Yu Wu
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xiaobing Wu
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Shengzhou Zhang
- Key Laboratory for Conservation and Use of Important Biological Resources of Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
| |
Collapse
|
2
|
Montalbano G, Levanti M, Abbate F, Laurà R, Cavallaro M, Guerrera MC, Germanà A. Expression of ghrelin and leptin in the chemosensory system of adult zebrafish. Ann Anat 2020; 229:151460. [PMID: 31978567 DOI: 10.1016/j.aanat.2020.151460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/10/2019] [Accepted: 01/06/2020] [Indexed: 11/19/2022]
Abstract
Numerous data show that the chemosensory system seems to be modulated by changes in the circulating levels of different molecules such as ghrelin, orexin, leptin, NPY, CCK. The chemosensory system of the zebrafish is represented by the taste buds (skin, oral and oropharyngeal), the olfactory rosette and the solitary chemosensorial cells (SCCs). The purpose of our study was to analyze the distribution of two peripheral hormones such as ghrelin and leptin in the chemosensory organs of the zebrafish. Our results demonstrated the presence of immunoreaction for all antibodies used in the zebrafish chemosensory organs even if with different distribution. In particular, IR was observed for ghrelin in the olfactory rosette while IR for leptin was found in the olfactory rosette, in the skin and oropharyngeal taste buds and in the gills. Both these hormones were detected in the intestine, used as a control.
Collapse
Affiliation(s)
- G Montalbano
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| | - M Levanti
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy.
| | - F Abbate
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| | - R Laurà
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| | - M Cavallaro
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| | - M C Guerrera
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| | - A Germanà
- Department of Veterinary Science, University of Messina, Neuromorphology Lab, Italy
| |
Collapse
|
3
|
Lo Cascio P, Calabrò C, Bertuccio C, Iaria C, Marino F, Denaro MG. Immunohistochemical Characterization of PepT1 and Ghrelin in Gastrointestinal Tract of Zebrafish: Effects of Spirulina Vegetarian Diet on the Neuroendocrine System Cells After Alimentary Stress. Front Physiol 2018; 9:614. [PMID: 29881359 PMCID: PMC5976732 DOI: 10.3389/fphys.2018.00614] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/07/2018] [Indexed: 12/28/2022] Open
Abstract
Gastrointestinal function in vertebrates is influenced by stressors, such as fasting and refeeding, different types of diet and hormonal factors. The aim of this paper was to analyze the effect of a Spirulina (Arthrospira platensis) diet, a microalga known for its nutraceutical properties, on the gastrointestinal tract of zebrafish (Danio rerio) regarding expression of oligopeptide transporter 1 (PepT1) and ghrelin (GHR). Food deprivation and refeeding was investigated to elucidate expression of PepT1 and GHR at a gastrointestinal level and the zebrafish compensatory mechanism. PepT1 is responsible for absorbing di- and tripeptides through a brush border membrane of intestinal mucosa. GHR is a brain-gut peptide in fish and mammals, stimulating growth hormone secretion and regulating appetite. Samples were taken after 2 and 5 days of specimen fasting, and 2 and 5 days of refeeding with Sera Spirulina tabs, in which the major constituent is Spirulina sp. (50.2% protein). Morphological and immunohistochemical analysis of PepT1 and GHR were carried out. Control specimen intestinal tract showed normal morphology of the digestive tract. Fasting caused fold structural changes and intestinal lumen constriction. Immunohistochemical analysis showed a PepT1 level reduction after fasting and an increase after refeeding, reaching very high levels after 5 days, compared to controls. GHR levels increased after food deprivation and gradually decreased after refeeding. Increased expression of PepT1 in refeeding fish suggests a compensatory physiological mechanism, as does the increase in GHR levels in fasting fish followed by a reduction after refeeding. A compensatory mechanism may be induced by fasting and refeeding and by a higher protein Spirulina diet. The microalga, for its nutraceutical properties, is an excellent candidate for animal breeding and human diet.
Collapse
Affiliation(s)
- Patrizia Lo Cascio
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| | - Concetta Calabrò
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| | - Clara Bertuccio
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| | - Carmelo Iaria
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| | - Fabio Marino
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| | - Maria G Denaro
- Department of Chemical, Biological, Pharmacological and Environmental Sciences, University of Messina, Messina, Italy
| |
Collapse
|
4
|
Song Y, Zhao C, Liang XF, He S, Tian C, Cheng X, Yuan X, Lv L, Guo W, Xue M, Tao YX. Effects of fasting, temperature, and photoperiod on preproghrelin mRNA expression in Chinese perch. FISH PHYSIOLOGY AND BIOCHEMISTRY 2017; 43:803-812. [PMID: 28321526 DOI: 10.1007/s10695-016-0335-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 12/18/2016] [Indexed: 06/06/2023]
Abstract
Preproghrelin, a gut/brain peptide, plays an important role in the regulation of food intake and energy homeostasis in teleost and mammals. In the present study, we obtained the full-length preproghrelin cDNA in Chinese perch. The preproghrelin messenger RNA (mRNA) tissue expression showed that level was much higher in stomach and pituitary than in other tissues. The fasting study showed, after gastric emptying (3-6 h), short-term fasting (6-12 h) increased preproghrelin expression in the stomach. While in the pituitary, fasting reduced preproghrelin expression at 1, 3, 12, and 48 h, presenting state fluctuation of self-adjustment. The temperature study showed that the mRNA expression of preproghrelin was the highest in the brain at 26 °C and highest in the stomach at 32 °C, respectively, with different optimum temperature in these two tissues, reflecting spatiotemporal differences of regulation by central nervous system and peripheral organs. The photoperiod study showed that normal light (11 h of lightness and 13 h of darkness) led to highest preproghrelin expression, both in the brain and in the stomach, than continuous light or continuous dark, proving food intake is adapted to natural photoperiod or normal light in this study. These results all indicated that tissue-specific preproghrelin expression of Chinese perch could be significantly affected by environmental factors. Short-term fasting of 6 h after gastric emptying, 26 °C, and normal light led to higher preproghrelin expression, which indicated potential appetite increase in Chinese perch.
Collapse
Affiliation(s)
- Yi Song
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Cheng Zhao
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Xu-Fang Liang
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China.
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China.
| | - Shan He
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Changxu Tian
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Xiaoyan Cheng
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Xiaochen Yuan
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Liyuan Lv
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Wenjie Guo
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovation 8 Center of Hubei Province, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan, 430070, China
| | - Min Xue
- National Aquafeed Safety Assessment Station, Feed Research Institute, the Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849, USA
| |
Collapse
|
5
|
Volkoff H. The Neuroendocrine Regulation of Food Intake in Fish: A Review of Current Knowledge. Front Neurosci 2016; 10:540. [PMID: 27965528 PMCID: PMC5126056 DOI: 10.3389/fnins.2016.00540] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/07/2016] [Indexed: 12/14/2022] Open
Abstract
Fish are the most diversified group of vertebrates and, although progress has been made in the past years, only relatively few fish species have been examined to date, with regards to the endocrine regulation of feeding in fish. In fish, as in mammals, feeding behavior is ultimately regulated by central effectors within feeding centers of the brain, which receive and process information from endocrine signals from both brain and peripheral tissues. Although basic endocrine mechanisms regulating feeding appear to be conserved among vertebrates, major physiological differences between fish and mammals and the diversity of fish, in particular in regard to feeding habits, digestive tract anatomy and physiology, suggest the existence of fish- and species-specific regulating mechanisms. This review provides an overview of hormones known to regulate food intake in fish, emphasizing on major hormones and the main fish groups studied to date.
Collapse
Affiliation(s)
- Helene Volkoff
- Departments of Biology and Biochemistry, Memorial University of NewfoundlandSt. John's, NL, Canada
| |
Collapse
|
6
|
Volkoff H. Cloning, tissue distribution and effects of fasting on mRNA expression levels of leptin and ghrelin in red-bellied piranha (Pygocentrus nattereri). Gen Comp Endocrinol 2015; 217-218:20-7. [PMID: 25980684 DOI: 10.1016/j.ygcen.2015.05.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 04/11/2015] [Accepted: 05/07/2015] [Indexed: 12/26/2022]
Abstract
cDNAs encoding the appetite regulating peptides leptin and ghrelin were isolated in red-bellied piranha (Characiforme, Serrasalmidae) and their mRNA tissue and brain distributions examined. When compared to other fish, the sequences obtained for all peptides were most similar to that of other Characiforme fish and Siluriformes. All peptides were widely expressed within the brain and in several peripheral tissues, including gastrointestinal tract. In order to better understand the role of these peptides in the regulation of feeding of red-bellied piranha, the mRNA expression levels of leptin and ghrelin were examined in both brain and intestine, in fed and 7-day fasted fish. No significant differences in expression were seen in whole brain for either peptide. Within the intestine, there was a decrease in leptin mRNA expression and an increase in ghrelin mRNA expression in fasted fish, compared to fed fish. The results suggest that leptin and ghrelin might play a major role in the regulation of feeding and energy homeostasis of red-bellied piranha and this role might be more prominent in the intestine than in the brain.
Collapse
Affiliation(s)
- Hélène Volkoff
- Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
| |
Collapse
|
7
|
Volkoff H. Cloning and tissue distribution of appetite-regulating peptides in pirapitinga (Piaractus brachypomus
). J Anim Physiol Anim Nutr (Berl) 2015; 99:987-1001. [DOI: 10.1111/jpn.12318] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 02/25/2015] [Indexed: 12/16/2022]
Affiliation(s)
- H. Volkoff
- Departments of Biology and Biochemistry; Memorial University of Newfoundland; St. John's NL Canada
| |
Collapse
|
8
|
Zhou C, Zhang X, Liu T, Wei R, Yuan D, Wang T, Lin F, Wu H, Chen F, Yang S, Chen D, Wang Y, Li Z. Schizothorax davidi ghrelin: cDNA cloning, tissue distribution and indication for its stimulatory character in food intake. Gene 2013; 534:72-7. [PMID: 24129070 DOI: 10.1016/j.gene.2013.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/25/2013] [Accepted: 10/07/2013] [Indexed: 01/31/2023]
Abstract
Ghrelin is a gut/brain hormone with a unique acyl modification and various biological functions in fish and mammals. The objectives of this project were to identify ghrelin gene organization, study tissue specific ghrelin mRNA expression and investigate the short- (0, 0.5, 1.5, 3, 6, 9, 12h post-fasting) and long- (1, 3, 5, 7 days) term fasting as well as refeeding after a 7 day fasting induced changes in the expression of ghrelin mRNA in Schizothorax davidi. Our reverse transcription polymerase chain reaction analysis confirmed the predicted ghrelin sequence available in the GenBank and identified ghrelin mRNA expression in several tissues including the gut, liver, brain, heart, spleen, head kidney, gill and muscle. Quantitative PCR studies indicated that the expression level of ghrelin mRNA presented ascendant trend in short-term fasting group compared to the fed group, but it did not reach the significant level on statistics, while there is a significant increase in ghrelin mRNA expression in the gut of Schizothorax davidi fasted for 3, 5 and 7 days when compared to the expression in ad libitum fed fish. Refeeding after a 7 day fasting caused a significant and dramatic decrease in ghrelin mRNA expression in the gut of Schizothorax davidi. An increase in the expression of ghrelin mRNA during fasting, and its decrease following refeeding suggests an orexigenic role for ghrelin in Schizothorax davidi. Overall, our results provide evidence for a highly conserved structure and biological actions of ghrelin during evolution.
Collapse
Affiliation(s)
- Chaowei Zhou
- Department of aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, Ya'an, China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
FENG KE, ZHANG GUIRONG, WEI KAIJIAN, XIONG BANGXI. Molecular Cloning, Tissue Distribution, and Ontogenetic Expression of Ghrelin and Regulation of Expression by Fasting and Refeeding in the Grass Carp (Ctenopharyngodon idellus). ACTA ACUST UNITED AC 2013; 319:202-12. [DOI: 10.1002/jez.1784] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 12/13/2012] [Accepted: 12/27/2012] [Indexed: 11/07/2022]
Affiliation(s)
- KE FENG
- Key Laboratory of Freshwater Animal Breeding; Ministry of Agriculture of China, College of Fisheries, Huazhong Agricultural University; Wuhan, P.R.; China
| | - GUI-RONG ZHANG
- Key Laboratory of Freshwater Animal Breeding; Ministry of Agriculture of China, College of Fisheries, Huazhong Agricultural University; Wuhan, P.R.; China
| | - KAI-JIAN WEI
- Key Laboratory of Freshwater Animal Breeding; Ministry of Agriculture of China, College of Fisheries, Huazhong Agricultural University; Wuhan, P.R.; China
| | - BANG-XI XIONG
- Key Laboratory of Freshwater Animal Breeding; Ministry of Agriculture of China, College of Fisheries, Huazhong Agricultural University; Wuhan, P.R.; China
| |
Collapse
|
10
|
Miandare HK, Farahmand H, Akbarzadeh A, Ramezanpour S, Kaiya H, Miyazato M, Rytkönen KT, Nikinmaa M. Developmental transcription of genes putatively associated with growth in two sturgeon species of different growth rate. Gen Comp Endocrinol 2013; 182:41-7. [PMID: 23229003 DOI: 10.1016/j.ygcen.2012.11.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/13/2012] [Accepted: 11/13/2012] [Indexed: 12/22/2022]
Abstract
In the present study, we surveyed developmental changes in the transcription of growth hormone (gh), insulin-like growth factor-I (igf-I), ghrelin (ghrl) and vascular endothelial growth factor (vegf) genes in the largest freshwater fish, European sturgeon (Beluga, Huso huso) and compared the same parameters to that of its phylogenically close moderate-sized species, Persian sturgeon (Acipenser persicus). The transcripts of gh, igf-I, ghrl and vegf were detected at all developmental time-points of Persian sturgeon and Beluga from embryos to juvenile fish. Changes in normalized gh, igf-I, ghrl and vegf transcription by using the geometric average of genes encoding ribosomal protein L6 (RPL6) and elongation factor (EF1A) over the time of development of Persian sturgeon and Beluga were statistically significant (P<0.05). Our results showed that the mRNA expression levels of both igf-I and ghrl were low during early larval development and then increased significantly to the late larval time-points when larvae started exogenous feeding. In both Beluga and Persian sturgeon, after a low mRNA expression during the embryonic stage, the transcript levels of vegf displayed an increasing trend during yolk-sac fry, consistent with organogenesis. The vegf level remained constantly high in the time of exogenous feeding. The highest detection of gh transcripts coincided with the end of the embryonic stage (hatching time) in Persian sturgeon and 3 days-post-hatching (dph) in Beluga. In Persian sturgeon, the gh transcript started to decrease to the rest of the developmental time-points, whereas in Beluga gh transcript had a marked second increase from the time of exogenous feeding (20-dph). This Beluga specific increase in gh transcription may be associated with the marked growth rate and extraordinary size of this fish species.
Collapse
Affiliation(s)
- Hamed Kolangi Miandare
- Department of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan 49138-15739, Iran.
| | | | | | | | | | | | | | | |
Collapse
|