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Bandara KA, Politis SN, Sørensen SR, Benini E, Tomkiewicz J, Vadstein O. Effect of Food Amounts on Larval Performance, Bacteriome and Molecular Immunologic Development during First-Feeding Culture of European Eel. Microorganisms 2024; 12:355. [PMID: 38399759 PMCID: PMC10892360 DOI: 10.3390/microorganisms12020355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Production of European eel offspring has become a reality, but liquid diets during larval culture hold new challenges. This study focused on increasing food amounts without compromising well-being or healthy larvae-bacteria interactions. First-feeding larvae were fed two food amounts (Low = 0.5 mL food/L water vs. High = 1.5 mL food/L water) until 30 days post-hatch (dph). Results indicated that ~75% of larvae ingested the diet in both treatments, but upregulation of a stress/repair-related gene (hsp90) on 25 and 30 dph indicated nutritional inadequacy. Larvae fed a High amount of food were 3.68% bigger, while larvae in the Low-food group showed 45.2% lower gut fullness and upregulated expression of the gene encoding the "hunger hormone" ghrelin (ghrl), indicating signs of starvation. The High-food group larvae exhibited a healthier bacteriome with a higher abundance of potentially beneficial orders (Lactobacillales and Bacillales), whereas the Low-food group showed more potentially harmful orders (Vibrionales, Rhodobacterales, and Alteromonadales). While survival was initially lower in the High-food group, both treatments had comparable survival by the end of the experiment. In conclusion, feeding European eel larvae with High food amounts seemed beneficial, supported by increased gut fullness, reduced ghrl expression (no starvation), enhanced growth, and the presence of a healthier bacteriome.
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Affiliation(s)
- Kasun Anuruddha Bandara
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Sebastian Nikitas Politis
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Sune Riis Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Elisa Benini
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (K.A.B.); (S.R.S.); (E.B.); (J.T.)
| | - Olav Vadstein
- Department of Biotechnology and Food Science, NTNU—Norwegian University of Science and Technology, 7491 Trondheim, Norway
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2
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Bandara KA, Benini E, Politis SN, Conceição LEC, Santos A, Sørensen SR, Tomkiewicz J, Vadstein O. Exploring bacterial community composition and immune gene expression of European eel larvae (Anguilla anguilla) in relation to first-feeding diets. PLoS One 2023; 18:e0288734. [PMID: 37498931 PMCID: PMC10373994 DOI: 10.1371/journal.pone.0288734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023] Open
Abstract
European eel (Anguilla anguilla) is a commercially important species for fisheries and aquaculture in Europe and the attempt to close the lifecycle in captivity is still at pioneering stage. The first feeding stage of this species is characterized by a critical period between 20 to 24 days post hatch (dph), which is associated with mortalities, indicating the point of no return. We hypothesized that this critical period might also be associated with larvae-bacterial interactions and the larval immune status. To test this, bacterial community composition and expression of immune and stress-related genes of hatchery-produced larvae were explored from the end of endogenous feeding (9 dph) until 28 dph, in response to three experimental first-feeding diets (Diet 1, Diet 2 and Diet 3). Changes in the water bacterial community composition were also followed. Results revealed that the larval stress/repair mechanism was activated during this critical period, marked by an upregulated expression of the hsp90 gene, independent of the diet fed. At the same time, a shift towards a potentially detrimental larval bacterial community was observed in all dietary groups. Here, a significant reduction in evenness of the larval bacterial community was observed, and several amplicon sequence variants belonging to potentially harmful bacterial genera were more abundant. This indicates that detrimental larvae-bacteria interactions were likely involved in the mortality observed. Beyond the critical period, the highest survival was registered for larvae fed Diet 3. Interestingly, genes encoding for pathogen recognition receptor TLR18 and complement component C1QC were upregulated in this group, potentially indicating a higher immunocompetency that facilitated a more successful handling of the harmful bacteria that dominated the bacterial community of larvae on 22 dph, ultimately leading to better survival, compared to the other two groups.
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Affiliation(s)
- Kasun A Bandara
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
- Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Elisa Benini
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Sebastian N Politis
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | | | - André Santos
- SPAROS Lda, Área Empresarial de Marim, Lote C, Olhão, Portugal
| | - Sune Riis Sørensen
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Jonna Tomkiewicz
- Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark
| | - Olav Vadstein
- Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
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3
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Chen J, Cai B, Tian C, Jiang D, Shi H, Huang Y, Zhu C, Li G, Deng S. RNA Sequencing (RNA-Seq) Analysis Reveals Liver Lipid Metabolism Divergent Adaptive Response to Low- and High-Salinity Stress in Spotted Scat ( Scatophagus argus). Animals (Basel) 2023; 13:ani13091503. [PMID: 37174540 PMCID: PMC10177406 DOI: 10.3390/ani13091503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Spotted scat (Scatophagus argus) can tolerate a wide range of salinity fluctuations. It is a good model for studying environmental salinity adaptation. Lipid metabolism plays an important role in salinity adaptation in fish. To elucidate the mechanism of lipid metabolism in the osmoregulation, the liver transcriptome was analyzed after 22 d culture with a salinity of 5 ppt (Low-salinity group: LS), 25 ppt (Control group: Ctrl), and 35 ppt (High-salinity group: HS) water by using RNA sequencing (RNA-seq) in spotted scat. RNA-seq analysis showed that 1276 and 2768 differentially expressed genes (DEGs) were identified in the LS vs. Ctrl and HS vs. Ctrl, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the pathways of steroid hormone biosynthesis, steroid biosynthesis, glycerophospholipid metabolism, glycerolipid metabolism, and lipid metabolism were significantly enriched in the LS vs. Ctrl. The genes of steroid biosynthesis (sqle, dhcr7, and cyp51a1), steroid hormone biosynthesis (ugt2a1, ugt2a2, ugt2b20, and ugt2b31), and glycerophospholipid metabolism (cept1, pla2g4a, and ptdss2) were significantly down-regulated in the LS vs. Ctrl. The pathways related to lipid metabolisms, such as fatty acid metabolism, fatty acid biosynthesis, peroxisome proliferator-activated receptor (PPAR) signaling pathway, adipocytokine signaling pathway, fatty acid degradation, and unsaturated fatty acid biosynthesis, were significantly enriched in the HS vs. Ctrl. The genes of unsaturated fatty acid biosynthesis (scd1, hacd3, fads2, pecr, and elovl1) and adipocytokine signaling pathway (g6pc1, socs1, socs3, adipor2, pck1, and pparα) were significantly up-regulated in the HS vs. Ctrl. These results suggest that the difference in liver lipid metabolism is important to adapt to low- and high-salinity stress in spotted scat, which clarifies the molecular regulatory mechanisms of salinity adaptation in euryhaline fish.
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Affiliation(s)
- Jieqing Chen
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
| | - Bosheng Cai
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
| | - Changxu Tian
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
| | - Dongneng Jiang
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
| | - Hongjuan Shi
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
| | - Yang Huang
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
| | - Chunhua Zhu
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
| | - Guangli Li
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
| | - Siping Deng
- Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Zhanjiang 524088, China
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Chen F, Wang Y, He J, Chen L, Xue G, Zhao Y, Peng Y, Smith C, Zhang J, Chen J, Xie P. Molecular Mechanisms of Spawning Habits for the Adaptive Radiation of Endemic East Asian Cyprinid Fishes. Research (Wash D C) 2022; 2022:9827986. [PMID: 36204246 PMCID: PMC9513835 DOI: 10.34133/2022/9827986] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/15/2022] [Indexed: 11/06/2022] Open
Abstract
Despite the widespread recognition of adaptive radiation as a driver of speciation, the mechanisms by which natural selection generates new species are incompletely understood. The evolutionary radiation of endemic East Asian cyprinids has been proposed as evolving through a change in spawning habits, involving a transition from semibuoyant eggs to adhesive eggs in response to crosslinked river-lake system formation. Here, we investigated the molecular mechanisms that underpin this radiation, associated with egg hydration and adhesiveness. We demonstrated that semibuoyant eggs enhance hydration by increasing the degradation of yolk protein and accumulation of Ca2+ and Mg2+ ions, while adhesive eggs improve adhesiveness and hardness of the egg envelope by producing an adhesive layer and a unique 4th layer to the egg envelope. Based on multiomics analyses and verification tests, we showed that during the process of adaptive radiation, adhesive eggs downregulated the “vitellogenin degradation pathway,” “zinc metalloprotease pathway,” and “ubiquitin-proteasome pathway” and the pathways of Ca2+ and Mg2+ active transport to reduce their hydration. At the same time, adhesive eggs upregulated the crosslinks of microfilament-associated proteins and adhesive-related proteins, the hardening-related proteins of the egg envelope, and the biosynthesis of glycosaminoglycan in the ovary to generate adhesiveness. These findings illustrate the novel molecular mechanisms associated with hydration and adhesiveness of freshwater fish eggs and identify critical molecular mechanisms involved in the adaptive radiation of endemic East Asian cyprinids. We propose that these key egg attributes may function as “magic traits” in this adaptive radiation.
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Affiliation(s)
- Feng Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yeke Wang
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun He
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Liang Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Ge Xue
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Zhao
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanghui Peng
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Carl Smith
- Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Jia Zhang
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Ping Xie
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- Institute of Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environment, Yunnan University, Kunming 650500, China
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5
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Sganga DE, Dahlke FT, Sørensen SR, Butts IAE, Tomkiewicz J, Mazurais D, Servili A, Bertolini F, Politis SN. CO2 induced seawater acidification impacts survival and development of European eel embryos. PLoS One 2022; 17:e0267228. [PMID: 35436318 PMCID: PMC9015118 DOI: 10.1371/journal.pone.0267228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 04/04/2022] [Indexed: 11/18/2022] Open
Abstract
Fish embryos may be vulnerable to seawater acidification resulting from anthropogenic carbon dioxide (CO2) emissions or from excessive biological CO2 production in aquaculture systems. This study investigated CO2 effects on embryos of the European eel (Anguilla anguilla), a catadromous fish that is considered at risk from climate change and that is targeted for hatchery production to sustain aquaculture of the species. Eel embryos were reared in three independent recirculation systems with different pH/CO2 levels representing “control” (pH 8.1, 300 μatm CO2), end-of-century climate change (“intermediate”, pH 7.6, 900 μatm CO2) and “extreme” aquaculture conditions (pH 7.1, 3000 μatm CO2). Sensitivity analyses were conducted at 4, 24, and 48 hours post-fertilization (hpf) by focusing on development, survival, and expression of genes related to acute stress response (crhr1, crfr2), stress/repair response (hsp70, hsp90), water and solute transport (aqp1, aqp3), acid-base regulation (nkcc1a, ncc, car15), and inhibitory neurotransmission (GABAAα6b, Gabra1). Results revealed that embryos developing at intermediate pH showed similar survival rates to the control, but egg swelling was impaired, resulting in a reduction in egg size with decreasing pH. Embryos exposed to extreme pH had 0.6-fold decrease in survival at 24 hpf and a 0.3-fold change at 48 compared to the control. These observed effects of acidification were not reflected by changes in expression of any of the here studied genes. On the contrary, differential expression was observed along embryonic development independent of treatment, indicating that the underlying regulating systems are under development and that embryos are limited in their ability to regulate molecular responses to acidification. In conclusion, exposure to predicted end-of-century ocean pCO2 conditions may affect normal development of this species in nature during sensitive early life history stages with limited physiological response capacities, while extreme acidification will negatively influence embryonic survival and development under hatchery conditions.
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Affiliation(s)
- Daniela E. Sganga
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
- * E-mail:
| | | | - Sune R. Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
- Billund Aquaculture, Billund, Denmark
| | - Ian A. E. Butts
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - David Mazurais
- CNRS, IRD, LEMAR, Ifremer, Université de Brest, Plouzané, France
| | - Arianna Servili
- CNRS, IRD, LEMAR, Ifremer, Université de Brest, Plouzané, France
| | - Francesca Bertolini
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Sebastian N. Politis
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
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Syropoulou E, Benini E, Sørensen SR, Butts IAE, Tomkiewicz J, Politis SN. Early and abrupt salinity reduction impacts European eel larval culture. FISH PHYSIOLOGY AND BIOCHEMISTRY 2022; 48:355-366. [PMID: 35156136 DOI: 10.1007/s10695-022-01056-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Reducing water salinity towards iso-osmotic conditions is a common practice applied in euryhaline fish farming to limit osmoregulation costs and enhance growth. In this respect, the present study investigated the timing of salinity reduction in an abrupt manner during European eel (Anguilla anguilla) larval culture by examining associated impacts on morphological and molecular levels. Larvae from 3 different parental combinations (families) were reared at constant 36 psu for 6 days (control) or subjected to a direct reduction to 18 psu on 1, 2, or 3 days post-hatch. Overall, salinity reduction enhanced growth and survival, resulting from more efficient energy resource utilization. In the control group, expression of growth-related igf2 remained constant, demonstrating a steady growth progression, while igf1 expression increased over time only for the salinity reduced treatments, potentially qualifying as a useful biomarker for growth performance. Even though each parental combination seems to have a different capacity to cope with salinity alterations, as observed by family-driven water-transport-related aquaporin (aqp1, aqp3) gene expression, it could be inferred that the abrupt salinity change is generally not stressful, based on non-upregulated heat shock proteins (hsp70, hsp90). However, the applied salinity reduction (irrespective of timing) induced the development of pericardial edema. As such, we conclude that despite the positive effect of salinity reduction on early growth and survival, the long-term benefit for eel larval culture lies in establishing a protocol for salinity reduction, at a precise developmental time point, without causing pericardial malformations.
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Affiliation(s)
- E Syropoulou
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
- Aquaculture and Fisheries Group, Wageningen University & Research, Wageningen, Netherlands
| | - E Benini
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - S R Sørensen
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
- Billund Aquaculture A/S, Billund, Denmark
| | - I A E Butts
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, USA
| | - J Tomkiewicz
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - S N Politis
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark.
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Benini E, Politis SN, Nielsen A, Sørensen SR, Tomkiewicz J, Engrola S. Type of hormonal treatment administered to induce vitellogenesis in European eel influences biochemical composition of eggs and yolk-sac larvae. FISH PHYSIOLOGY AND BIOCHEMISTRY 2022; 48:185-200. [PMID: 35044583 PMCID: PMC8844165 DOI: 10.1007/s10695-021-01042-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
Egg biochemical composition is among the main factors affecting offspring quality and survival during the yolk-sac stage, when larvae depend exclusively on yolk nutrients. These nutrients are primarily embedded in the developing oocytes during vitellogenesis. In aquaculture, assisted reproduction procedures may be applied enabling gamete production. For the European eel (Anguilla anguilla), reproductive treatment involves administration of pituitary extracts from carp (CPE) or salmon (SPE) to induce and sustain vitellogenesis. In the present study, we compared the influence of CPE and SPE treatments on offspring quality and composition as well as nutrient utilization during the yolk-sac stage. Thus, dry weight, proximal composition (total lipid, total protein), free amino acids, and fatty acids were assessed in eggs and larvae throughout the yolk-sac stage, where body and oil-droplet area were measured to estimate growth rate, oil-droplet utilization, and oil-droplet utilization efficiency. The results showed that CPE females spawned eggs with higher lipid and free amino acid contents. However, SPE females produced more buoyant eggs with higher fertilization rate as well as larger larvae with more energy reserves (estimated as oil-droplet area). Overall, general patterns of nutrient utilization were detected, such as the amount of total lipid and monounsaturated fatty acids decreasing from the egg stage and throughout the yolk-sac larval stage. On the contrary, essential fatty acids and free amino acids were retained. Notably, towards the end of the yolk-sac stage, the proximal composition and biometry of surviving larvae, from both treatments, were similar.
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Affiliation(s)
- E Benini
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark.
| | - S N Politis
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - A Nielsen
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - S R Sørensen
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - J Tomkiewicz
- Technical University of Denmark, National Institute of Aquatic Resources, Kgs. Lyngby, Denmark
| | - S Engrola
- Centre of Marine Sciences, Universidade Do Algarve, Faro, Portugal
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8
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Chen F, Smith C, Wang Y, He J, Xia W, Xue G, Chen J, Xie P. The Evolution of Alternative Buoyancy Mechanisms in Freshwater Fish Eggs. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.736718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Alternative reproductive tactics (ARTs) are behavioural, morphological, and physiological traits associated with alternative reproductive phenotypes within a population or species. ARTs are widespread in nature, and are a particular feature of teleost fishes. However, few studies have examined egg buoyancy mechanisms in the context of the evolution of ARTs in freshwater fishes. In marine fishes, egg buoyancy is achieved chiefly through hydration. While the buoyancy of freshwater fish eggs has been suggested to be determined primarily through the presence of oil droplets, the majority (60%) of freshwater pelagic eggs do not possess an oil droplet. We applied a physical model of buoyancy to understand the contributions of oil droplets and hydration to the buoyancy of pelagic freshwater fish eggs. We further used phylogenetic regression to estimate the effect of the relative size of the perivitelline space, habitat and parental care on the occurrence of oil droplets, while controlling for non-independence among species due to phylogenetic relatedness. Our analysis demonstrates that the probability of oil droplets in freshwater pelagic eggs exhibits a significant negative relationship with the size of perivitelline space, which may reflect a trade-off relating to energy allocation in contrasting habitats. We also demonstrate a positive association between the probability of oil droplets and the provision of parental care and occupancy of lentic habitats. These findings indicates the evolution of contrasting buoyancy mechanisms as novel ARTs in freshwater fishes. A theoretical model in combination with empirical analysis indicate the evolution of novel ARTs in freshwater fishes as adaptive responses to flow conditions.
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Kottmann JS, Tveiten H, Miest JJ, Tomkiewicz J. Sex steroid dynamics and mRNA transcript profiles of growth- and development-related genes during embryogenesis following induced follicular maturation in European eel. Gen Comp Endocrinol 2021; 311:113854. [PMID: 34265345 DOI: 10.1016/j.ygcen.2021.113854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 12/24/2022]
Abstract
Hormones and mRNA transcripts of maternal origin deposited in the egg may affect early embryonic development in oviparous species. These hormones include steroids, such as estradiol-17β (E2), testosterone (T), 11-ketotestosterone (11-kt), 17α,20ß-dihydroxy-4-pregnen-3-one (DHP), and cortisol, which also play an important role in fish reproduction. In European eel, Anguilla anguilla, which does not reproduce naturally in captivity, vitellogenesis in female broodstock is commonly induced by administration of salmon or carp pituitary extract (PE) as an exogenous source of gonadotropins, while follicular maturation is stimulated by a priming dose of PE followed by provision of DHP as a maturation inducing hormone. In this regard, the main purpose of the present study was to evaluate effects of induced follicular maturation on reproductive success in European eel, focusing on maternal transfer and dynamics of steroids and mRNA transcripts of growth- and development-related genes throughout embryogenesis. The results showed that maternal blood plasma concentrations of E2, T and DHP were reflected in the unfertilized eggs. Moreover, a negative relationship between concentrations of E2 and DHP in eggs and embryos and quality parameters measured as fertilization success, cleavage abnormalities, embryonic survival, and hatch success was found. Concomitant mRNA transcript abundance analysis including genes involved in stress response (hsp70, hsp90), somatotropic axis (gh, igf1, igf2a, igf2b), lipid (cpt1a, cpt1b, pigf5) and thyroid metabolism (dio1, dio2, dio3, thrαb, thrβa, thrβb) varied among unfertilized egg batches. For the majority of genes, mRNA abundance increased during the maternal-to-zygotic transition in connection to activation of the transcription of the embryos own genome. mRNA abundance of dio1, cpt1a and cpt1b throughout embryogenesis was related to embryonic developmental competence. Notably, mRNA abundance of dio3 was positively associated with E2 concentrations, while the mRNA abundance of thrαb was negatively related to T concentrations in the unfertilized eggs, which may suggest an interaction between the thyroid and steroid hormone systems. Altogether, maternal plasma concentrations of E2 and DHP were reflected in the eggs, with high concentrations of these steroids in the eggs being negatively associated with embryonic developmental competence. Additionally, high transcript levels of two of the investigated genes (dio1, cpt1b) were positively associated with embryonic developmental competence. This study reveals maternal transfer of steroids and mRNA transcripts to the eggs, which may be significant contributors to the variability in embryonic survival observed in European eel captive reproduction.
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Affiliation(s)
- Johanna S Kottmann
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | - Helge Tveiten
- UiT Arctic University of Norway, 9019 Tromsø, Norway
| | - Joanna J Miest
- School of Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, United Kingdom
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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10
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Piñosa LAG, Amar MJA, Capaque TPV, Laureta LV, Pedroso FL, Rendaje DC, Cadangin JF, Maquirang JRH, Mero FFC. Effects of sperm to egg ratio, stocking density, delay of gamete contact, temperature and salinity on fertilisation success and D-larvae production of green mussel, Perna viridis. MOLLUSCAN RESEARCH 2020. [DOI: 10.1080/13235818.2020.1836715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Lily Anne G. Piñosa
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Mary Jane A. Amar
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Thereze Pauline V. Capaque
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Liberato V. Laureta
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Fiona L. Pedroso
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
- Mindanao State University – Naawan, Naawan, Philippines
| | - Donna C. Rendaje
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Josel F. Cadangin
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
| | - Jean Rose H. Maquirang
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
- College of Fisheries and Marine Sciences, Aklan State University – New Washington, New Washington, Philippines
| | - Fedelia Flor C. Mero
- Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Iloilo, Philippines
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11
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Chang YLK, Dall’Olmo G, Schabetsberger R. Tracking the marine migration routes of South Pacific silver eels. MARINE ECOLOGY PROGRESS SERIES 2020; 646:1-12. [PMID: 33364670 PMCID: PMC7116496 DOI: 10.3354/meps13398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Three catadromous Pacific eels (2 Anguilla marmorata, 1 A. megastoma) from the Archipelago of Vanuatu were tagged with pop-up satellite archival transmitters and their migration tracks towards their presumed spawning area approximately 870 km northeast of the point of release were reconstructed in order to evaluate their movements in relation to oceanographic conditions. We used the timing of diel vertical migrations to derive the eels' positions. Two A. marmorata exhibited steep-angled turns resulting in a zig-zag migration path along the east-west axis, while one A. megastoma took a relatively straight course towards the presumed spawning area. They migrated with a speed over ground of 21-23 km day-1. In this region, the eastward flow of the South Equatorial Counter Current (SECC, ∼ 5-10°S) separates the westward flowing South Equatorial Current (SEC; ∼0-5°S and 10-18°S) into two branches. During shallower nighttime migration depths around 150 m eels crossed a variable flow field through the southern branch of the westward SEC with westward propagating mesoscale eddies and the eastward SECC, but stayed south of the stronger northern branch of SEC possibly increasing retention time of larvae within this area. The eels headed towards a tongue of high-salinity Subtropical Underwater (STUW) that may have provided cues for orientation. The eels did not move beyond a salinity front of 35.9-36.0 at a depth of 100-200 m, which may have provided cues for orientation towards the spawning area. These 3 tracks may represent the movements of mature silver eels all the way to where they spawn.
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Affiliation(s)
- Yu-Lin K. Chang
- Application Laboratory, Japan Agency of Marine-Earth Science and Technology, Yokohama, Japan
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12
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Kottmann JS, Jørgensen MGP, Bertolini F, Loh A, Tomkiewicz J. Differential impacts of carp and salmon pituitary extracts on induced oogenesis, egg quality, molecular ontogeny and embryonic developmental competence in European eel. PLoS One 2020; 15:e0235617. [PMID: 32634160 PMCID: PMC7340298 DOI: 10.1371/journal.pone.0235617] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 06/19/2020] [Indexed: 12/26/2022] Open
Abstract
Low egg quality and embryonic survival are critical challenges in aquaculture, where assisted reproduction procedures and other factors may impact egg quality. This includes European eel (Anguilla anguilla), where pituitary extract from carp (CPE) or salmon (SPE) is applied to override a dopaminergic inhibition of the neuroendocrine system, preventing gonadotropin secretion and gonadal development. The present study used either CPE or SPE to induce vitellogenesis in female European eel and compared impacts on egg quality and offspring developmental competence with emphasis on the maternal-to-zygotic transition (MZT). Females treated with SPE produced significantly higher proportions of floating eggs with fewer cleavage abnormalities and higher embryonic survival. These findings related successful embryogenesis to higher abundance of mRNA transcripts of genes involved in cell adhesion, activation of MZT, and immune response (dcbld1, epcam, oct4, igm) throughout embryonic development. The abundance of mRNA transcripts of cldnd, foxr1, cea, ccna1, ccnb1, ccnb2, zar1, oct4, and npm2 was relatively stable during the first eight hours, followed by a drop during MZT and low levels thereafter, indicating transfer and subsequent clearance of maternal mRNA. mRNA abundance of zar1, epcam, and dicer1 was associated with cleavage abnormalities, while mRNA abundance of zar1, sox2, foxr1, cldnd, phb2, neurod4, and neurog1 (before MZT) was associated with subsequent embryonic survival. In a second pattern, low initial mRNA abundance with an increase during MZT and higher levels persisting thereafter indicating the activation of zygotic transcription. mRNA abundance of ccna1, npm2, oct4, neurod4, and neurog1 during later embryonic development was associated with hatch success. A deviating pattern was observed for dcbld1, which mRNA levels followed the maternal-effect gene pattern but only for embryos from SPE treated females. Together, the differences in offspring production and performance reported in this study show that PE composition impacts egg quality and embryogenesis and in particular, the transition from initial maternal transcripts to zygotic transcription.
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Affiliation(s)
- Johanna S. Kottmann
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Francesca Bertolini
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Adrian Loh
- School of Science, University of Greenwich, Chatham Maritime, Kent, United Kingdom
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, Kgs. Lyngby, Denmark
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13
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Romney ALT, Yanagitsuru YR, Mundy PC, Fangue NA, Hung TC, Brander SM, Connon RE. Developmental Staging and Salinity Tolerance in Embryos of the Delta Smelt, Hypomesus transpacificus. AQUACULTURE (AMSTERDAM, NETHERLANDS) 2019; 511:634191. [PMID: 32831418 PMCID: PMC7442155 DOI: 10.1016/j.aquaculture.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Delta smelt (Hypomesus transpacificus) is a critically endangered species endemic to the San Francisco Bay Delta (SFBD). Important for the conservation of this species is understanding the physiological and ecological impacts contributing to their population decline, and current studies lack information on embryonic development. Changes in patterns of salinity across the SFBD may be a particularly important environmental stressor contributing to the recruitment and survival of the species. Throughout their ontogeny, delta smelt may exhibit unique requirements and tolerances to environmental conditions including salinity. Here, we describe 22 stages of embryonic development of H. transpacificus that characterize early differentiation from the fertilized egg until hatching, allowing the identification of critical morphological features unique to this species. Additionally, we investigated aspects of physiological tolerance to environmental salinity during development. Embryos survived incubation at salinity treatments between 0.4 and 20 ppt, yet had lower hatch success at higher salinities. Prior to hatching, embryos exposed to higher salinities had increased osmolalities and reduced fractions of yolk implying that the elevated external salinity altered the physiology of the embryo and the environment internal to the chorion. Lastly, egg activation and fertilization appear to also be impacted by salinity. Altogether, we suggest that any potential tolerance to salinity during embryogenesis, a common feature in euryhaline teleost species, impacts life cycle transitions into, and out of, embryonic development. Results from this investigation should improve conservation and management practices of this species and further expand our understanding of the intimate relationship between an embryo and its environment.
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Affiliation(s)
- Amie L. T. Romney
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, CA 95616, USA
| | - Yuzo R. Yanagitsuru
- Department of Wildlife Conservation and Fish Biology, University of California, Davis, CA 95616, USA
| | - Paige C. Mundy
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, CA 95616, USA
| | - Nann A. Fangue
- Department of Wildlife Conservation and Fish Biology, University of California, Davis, CA 95616, USA
| | - Tien-Chieh Hung
- Fish Conservation Culture Laboratory, Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA
| | - Susanne M. Brander
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA
| | - Richard E. Connon
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, CA 95616, USA
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14
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15
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Gao Q, Yue Y, Min M, Peng S, Shi Z, Wang J, Zhang T. Time-series transcriptomic analysis of the kelp grouper Epinephelus moara in response to low salinity stress. Anim Cells Syst (Seoul) 2018; 22:234-242. [PMID: 30460103 PMCID: PMC6138362 DOI: 10.1080/19768354.2018.1487335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/27/2018] [Accepted: 05/21/2018] [Indexed: 11/25/2022] Open
Abstract
The Kelp grouper Epinephelus moara is one of the most widely consumed and economically important marine fish in China. The species can tolerate a wide range of salinity, but genomic resources are not available, and the molecular mechanisms underlying adaptation to salinity at the transcriptomic level remain largely unclear. In this study, the transcriptomic responses of the liver of E. moara under low salinity were investigated using the Illumina digital gene expression system. After de novo assembly, 499,356 transcripts were generated and contributed 445,068 unigenes. A total of 14, 19, 33 and 3101 genes were differentially expressed following exposure to low salinity stress for 2, 6, 24 and 48 h, respectively. Only two genes were differentially expressed in all groups. Four genes related to metabolism and ambient salinity adaption were randomly selected to validate the differentially expressed genes (DEGs) by real-time PCR. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to analyse the functional significance of DEGs, including those responding to salinity through diverse biological processes, cellular components, molecular functions, and pathways associated with metabolic and osmotic responses. This work provides new insight into the response to salinity challenges in E. moara, and the findings expand our knowledge of the molecular basis of metabolic regulation mechanisms in this species. Additionally, the transcriptional data provide a valuable resource for future molecular and genetic studies on E. moara.
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Affiliation(s)
- Quanxin Gao
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, People's Republic of China
| | - Yanfeng Yue
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, People's Republic of China
| | - Minghua Min
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, People's Republic of China
| | - Shiming Peng
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, People's Republic of China
| | - Zhaohong Shi
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai, People's Republic of China
| | - Jinbo Wang
- Ningbo Institute of Technology, Zhejiang University, Ningbo, People's Republic of China
| | - Tao Zhang
- Aquatic Technology Promoting Station of Meijiang District, Meizhou, People's Republic of China
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16
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Politis SN, Sørensen SR, Mazurais D, Servili A, Zambonino-Infante JL, Miest JJ, Clemmesen CM, Tomkiewicz J, Butts IAE. Molecular Ontogeny of First-Feeding European Eel Larvae. Front Physiol 2018; 9:1477. [PMID: 30459634 PMCID: PMC6232945 DOI: 10.3389/fphys.2018.01477] [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: 03/20/2018] [Accepted: 09/28/2018] [Indexed: 12/28/2022] Open
Abstract
Digestive system functionality of fish larvae relies on the onset of genetically pre-programmed and extrinsically influenced digestive functions. This study explored how algal supplementation (green-water) until 14 days post hatch (dph) and the ingestion of food [enriched rotifer (Brachionus plicatilis) paste] from 15 dph onward affects molecular maturation and functionality of European eel larval ingestion and digestion mechanisms. For this, we linked larval biometrics to expression of genes relating to appetite [ghrelin (ghrl), cholecystokinin (cck)], food intake [proopiomelanocortin (pomc)], digestion [trypsin (try), triglyceride lipase (tgl), amylase (amyl)], energy metabolism [ATP synthase F0 subunit 6 (atp6), cytochrome-c-oxidase 1 (cox1)], growth [insulin-like growth factor (igf1)] and thyroid metabolism [thyroid hormone receptors (thrαA, thrβB)]. Additionally, we estimated larval nutritional status via nucleic acid analysis during transition from endogenous and throughout the exogenous feeding stage. Results showed increased expression of ghrl and cck on 12 dph, marking the beginning of the first-feeding window, but no benefit of larviculture in green-water was observed. Moreover, expression of genes relating to protein (try) and lipid (tgl) hydrolysis revealed essential digestive processes occurring from 14 to 20 dph. On 16 dph, a molecular response to initiation of exogenous feeding was observed in the expression patterns of pomc, atp6, cox1, igf1, thrαA and thrβB. Additionally, we detected increased DNA contents, which coincided with increased RNA contents and greater body area, reflecting growth in feeding compared to non-feeding larvae. Thus, the here applied nutritional regime facilitated a short-term benefit, where feeding larvae were able to sustain growth and better condition than their non-feeding conspecifics. However, RNA:DNA ratios decreased from 12 dph onward, indicating a generally low larval nutritional condition, probably leading to the point-of-no-return and subsequent irreversible mortality due to unsuccessful utilization of exogenous feeding. In conclusion, this study molecularly identified the first-feeding window in European eel and revealed that exogenous feeding success occurs concurrently with the onset of a broad array of enzymes and hormones, which are known to regulate molecular processes in feeding physiology. This knowledge constitutes essential information to develop efficient larval feeding strategies and will hopefully provide a promising step toward sustainable aquaculture of European eel.
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Affiliation(s)
- Sebastian N Politis
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sune R Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark.,Billund Aquaculture Service A/S, Billund, Denmark
| | - David Mazurais
- Marine Environmental Science Laboratory UMR 6539, Institut Français de Recherche pour l'Exploitation de la Mer, Plouzané, France
| | - Arianna Servili
- Marine Environmental Science Laboratory UMR 6539, Institut Français de Recherche pour l'Exploitation de la Mer, Plouzané, France
| | - Jose-Luis Zambonino-Infante
- Marine Environmental Science Laboratory UMR 6539, Institut Français de Recherche pour l'Exploitation de la Mer, Plouzané, France
| | - Joanna J Miest
- GEOMAR - Helmholtz Centre for Ocean Research, Kiel, Germany.,Department of Life and Sports Sciences, University of Greenwich, Kent, United Kingdom
| | | | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Ian A E Butts
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark.,School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL, United States
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17
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Benini E, Politis SN, Kottmann JS, Butts IAE, Sørensen SR, Tomkiewicz J. Effect of parental origin on early life history traits of European eel. Reprod Domest Anim 2018; 53:1149-1158. [PMID: 29938848 DOI: 10.1111/rda.13219] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/15/2018] [Accepted: 05/01/2018] [Indexed: 01/15/2023]
Abstract
Establishment of European eel (Anguilla anguilla) hatchery production will rely on selectively bred individuals that produce progeny with the best traits in successive generations. As such, this study used a quantitative genetic breeding design, between four females and nine males (four wild-caught and five cultured), to investigate the effect of paternal origin (wild-caught vs. cultured) and quantify the relative importance of parental effects, including genetic compatibility, on early life history (ELH) performance traits (i.e. fertilization success, embryonic survival at 32 hr post-fertilization, hatch success and larval deformities at 2 days post-hatch) of European eel. Wild-caught males had higher (56%) spermatocrit values than cultured males (45%), while fertilization success, embryonic survival, hatch success and larval deformities were not significantly impacted by paternal origin. This demonstrates that short-term domestication of male eels does not negatively affect offspring quality and enables the consideration of cultured male broodstock in future breeding programmes. Moreover, paternity significantly explained 9.5% of the variability in embryonic survival, providing further evidence that paternal effects need to be taken into consideration in assisted reproduction protocols. Furthermore, maternity significantly explained 54.8% of the variation for fertilization success, 61.7% for embryonic survival, 88.1% for hatching success and 62.8% for larval deformities, validating that maternity is a major factor influencing these "critical" ELH traits. At last, the parental interaction explained 12.8% of the variation for fertilization success, 8.3% for embryonic survival, 4.5% for hatch success and 20.5% for larval deformities. Thus, we conclude that eggs of one female can develop more successfully when crossed with a compatible male, highlighting the importance of mate choice for successful propagation of high-quality offspring. Together, this knowledge will improve early offspring performance, leading to future breeding programmes for this critically endangered and economically important species.
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Affiliation(s)
| | - Sebastian N Politis
- National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen, Denmark
| | - Johanna S Kottmann
- National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen, Denmark
| | - Ian A E Butts
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, Alabama
| | - Sune R Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen, Denmark.,Billund Aquaculture Service, Billund, Denmark
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen, Denmark
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18
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Politis SN, Mazurais D, Servili A, Zambonino-Infante JL, Miest JJ, Tomkiewicz J, Butts IAE. Salinity reduction benefits European eel larvae: Insights at the morphological and molecular level. PLoS One 2018; 13:e0198294. [PMID: 29897966 PMCID: PMC5999099 DOI: 10.1371/journal.pone.0198294] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/16/2018] [Indexed: 11/23/2022] Open
Abstract
European eel (Anguilla anguilla) is a euryhaline species, that has adapted to cope with both, hyper- and hypo-osmotic environments. This study investigates the effect of salinity, from a morphological and molecular point of view on European eel larvae reared from 0 to 12 days post hatch (dph). Offspring reared in 36 practical salinity units (psu; control), were compared with larvae reared in six scenarios, where salinity was decreased on 0 or 3 dph and in rates of 1, 2 or 4 psu/day, towards iso-osmotic conditions. Results showed that several genes relating to osmoregulation (nkcc2α, nkcc2β, aqp1dup, aqpe), stress response (hsp70, hsp90), and thyroid metabolism (thrαA, thrαB, thrβB, dio1, dio2, dio3) were differentially expressed throughout larval development, while nkcc1α, nkcc2β, aqp3, aqp1dup, aqpe, hsp90, thrαA and dio3 showed lower expression in response to the salinity reduction. Moreover, larvae were able to keep energy metabolism related gene expression (atp6, cox1) at stable levels, irrespective of the salinity reduction. As such, when reducing salinity, an energy surplus associated to reduced osmoregulation demands and stress (lower nkcc, aqp and hsp expression), likely facilitated the observed increased survival, improved biometry and enhanced growth efficiency. Additionally, the salinity reduction decreased the amount of severe deformities such as spinal curvature and emaciation but also induced an edematous state of the larval heart, resulting in the most balanced mortality/deformity ratio when salinity was decreased on 3 dph and at 2 psu/day. However, the persistency of the pericardial edema and if or how it represents an obstacle in further larval development needs to be further clarified. In conclusion, this study clearly showed that salinity reduction regimes towards iso-osmotic conditions facilitated the European eel pre-leptocephalus development and revealed the existence of highly sensitive and regulated osmoregulation processes at such early life stage of this species.
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Affiliation(s)
- Sebastian N. Politis
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
- * E-mail:
| | - David Mazurais
- Ifremer, Marine Environmental Science Laboratory UMR 6539, Plouzané, France
| | - Arianna Servili
- Ifremer, Marine Environmental Science Laboratory UMR 6539, Plouzané, France
| | | | | | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
| | - Ian A. E. Butts
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
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19
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Müller T, Matsubara H, Kubara Y, Horváth Á, Kolics B, Taller J, Stéger V, Kovács B, Horváth L, Asturiano JF, Peñaranda DS, Urbányi B. Testing cryopreserved European eel sperm for hybridization (A. japonica × A. anguilla). Theriogenology 2018. [DOI: 10.1016/j.theriogenology.2018.02.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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20
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Politis SN, Mazurais D, Servili A, Zambonino-Infante JL, Miest JJ, Sørensen SR, Tomkiewicz J, Butts IAE. Temperature effects on gene expression and morphological development of European eel, Anguilla anguilla larvae. PLoS One 2017; 12:e0182726. [PMID: 28806748 PMCID: PMC5555698 DOI: 10.1371/journal.pone.0182726] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/24/2017] [Indexed: 12/02/2022] Open
Abstract
Temperature is important for optimization of rearing conditions in aquaculture, especially during the critical early life history stages of fish. Here, we experimentally investigated the impact of temperature (16, 18, 20, 22 and 24°C) on thermally induced phenotypic variability, from larval hatch to first-feeding, and the linked expression of targeted genes [heat shock proteins (hsp), growth hormone (gh) and insulin-like growth factors (igf)] associated to larval performance of European eel, Anguilla anguilla. Temperature effects on larval morphology and gene expression were investigated throughout early larval development (in real time from 0 to 18 days post hatch) and at specific developmental stages (hatch, jaw/teeth formation, and first-feeding). Results showed that hatch success, yolk utilization efficiency, survival, deformities, yolk utilization, and growth rates were all significantly affected by temperature. In real time, increasing temperature from 16 to 22°C accelerated larval development, while larval gene expression patterns (hsp70, hsp90, gh and igf-1) were delayed at cold temperatures (16°C) or accelerated at warm temperatures (20–22°C). All targeted genes (hsp70, hsp90, gh, igf-1, igf-2a, igf-2b) were differentially expressed during larval development. Moreover, expression of gh was highest at 16°C during the jaw/teeth formation, and the first-feeding developmental stages, while expression of hsp90 was highest at 22°C, suggesting thermal stress. Furthermore, 24°C was shown to be deleterious (resulting in 100% mortality), while 16°C and 22°C (~50 and 90% deformities respectively) represent the lower and upper thermal tolerance limits. In conclusion, the high survival, lowest incidence of deformities at hatch, high yolk utilization efficiency, high gh and low hsp expression, suggest 18°C as the optimal temperature for offspring of European eel. Furthermore, our results suggest that the still enigmatic early life history stages of European eel may inhabit the deeper layer of the Sargasso Sea and indicate vulnerability of this critically endangered species to increasing ocean temperature.
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Affiliation(s)
- Sebastian N. Politis
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
- * E-mail:
| | - David Mazurais
- Ifremer, Marine Environmental Science Laboratory UMR 6539, Plouzané, France
| | - Arianna Servili
- Ifremer, Marine Environmental Science Laboratory UMR 6539, Plouzané, France
| | | | | | - Sune R. Sørensen
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
| | - Jonna Tomkiewicz
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
| | - Ian A. E. Butts
- National Institute of Aquatic Resources, Technical University of Denmark, DTU, Lyngby, Denmark
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21
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Kawakami T, Yamada Y, Tanaka S, Tsukamoto K. Prolongation of somitogenesis in two anguilliform species, the Japanese eel Anguilla japonica and pike eel Muraenesox cinereus, with refined descriptions of their early development. JOURNAL OF FISH BIOLOGY 2017; 90:1533-1547. [PMID: 28097653 DOI: 10.1111/jfb.13249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 11/13/2015] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
The embryonic development of the Japanese eel Anguilla japonica and pike eel Muraenesox cinereus was morphologically investigated with laboratory-reared specimens to clarify the characteristics of somitogenesis. In A. japonica, somites were first observed at 18 h post fertilization (hpf) when epiboly reached 90%. Somitogenesis progressed at a rate of 1·6 h-1 at mean ± s.d. 22·6 ± 0·7° C and completed at 107 hpf (3 days post hatching; dph) when total number of somites (ST) reached 114, which corresponds to the species' number of vertebrae (112-119). In M. cinereus, somites were first observed at 14 hpf when epiboly completed. Somitogenesis progressed at a rate of 1·9 h-1 at mean ± s.d. 24·4 ± 0·2° C and completed at 90 hpf (2 dph) with 149 ± 4 ST, which corresponds to the species' number of vertebrae (142-158). Both species hatched before somitogenesis was completed, at 37 hpf with 47 ST and 42 hpf with 82 ± 4 ST, respectively. The formation of other organs such as the heart, mouth and pectoral fin bud occurred during somitogenesis. Comparison with the development of zebrafish Danio rerio indicates a prolongation of somitogenesis in A. japonica and M. cinereus. Their somitogenesis rates, however, correspond well with that of D. rerio estimated at the same temperature and their developmental stages at hatching are almost equivalent to other fishes having similar yolk sizes. Therefore, the prolongation of somitogenesis in A. japonica and M. cinereus may be accounted for solely by the increased numbers of somites to be formed, not by a slow somitogenesis rate or an acceleration in organogenesis.
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Affiliation(s)
- T Kawakami
- Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
- Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Y Yamada
- IRAGO Institute, 377 Ehima-Shinden, Tahara, Aichi, 441-3605, Japan
| | - S Tanaka
- IRAGO Institute, 377 Ehima-Shinden, Tahara, Aichi, 441-3605, Japan
| | - K Tsukamoto
- Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
- College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa, 252-0880, Japan
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22
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Schabetsberger R, Miller MJ, Dall’Olmo G, Kaiser R, Økland F, Watanabe S, Aarestrup K, Tsukamoto K. The hydrographic features of anguillid spawning areas: potential signposts for migrating eels. MARINE ECOLOGY PROGRESS SERIES 2016; 554:141-155. [PMID: 33184524 PMCID: PMC7116345 DOI: 10.3354/meps11824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Catadromous anguillid eels (Genus Anguilla) migrate from their freshwater or estuarine habitats to marine spawning areas. Evidence from satellite tagging studies indicates that tropical and temperate eel species exhibit pronounced diel vertical migrations between 150 to 300 m nighttime depths to 600 to 800 m during the day. Collections of eggs and larvae of Japanese eels (A. japonica) show they may spawn at these upper nighttime migration depths. How anguillid eels navigate through the ocean and find their spawning areas remains unknown, so this study describes the salinity, temperature and geostrophic currents between 0 and 800 m depths within two confirmed and three hypothetical anguillid spawning areas during likely spawning seasons. Within all four ocean gyres many eels would encounter subducted 'Subtropical Underwater' during their nighttime ascents that could provide odor plumes as signposts. Four spawning areas are located near the western margins of where subducted water masses form cores of elevated salinities (~35.0 to 36.8) around 150 m depths, while one is found near the center of subduction. Low salinity surface waters and fronts are present in some of the areas above the high-salinity cores. Spawning may occur at temperatures between 16 to 24°C where the thermocline locally deepens. At spawning depths, weak westward currents (~0 to 0.1 m s-1) prevail, and eastward surface countercurrents are present. Anguillid eels possess acute sensory capabilities to detect these hydrographic features as potential signposts guiding them to where they spawn.
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Affiliation(s)
| | - Michael J. Miller
- College of Bioresource Sciences, Nihon University, Kanagawa 52-0880, Japan
| | | | - Roland Kaiser
- University of Salzburg, Department of Cell Biology, 5020 Salzburg, Austria
| | - Finn Økland
- The Norwegian Institute of Nature Research, 7047 Trondheim, Norway
| | - Shun Watanabe
- College of Bioresource Sciences, Nihon University, Kanagawa 52-0880, Japan
| | - Kim Aarestrup
- Technical University of Denmark, National Institute of Aquatic Resources,8600 Silkeborg, Denmark
| | - Katsumi Tsukamoto
- College of Bioresource Sciences, Nihon University, Kanagawa 52-0880, Japan
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23
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Asturiano JF, Sørensen SR, Pérez L, Lauesen P, Tomkiewicz J. First Production of Larvae Using Cryopreserved Sperm: Effects of Preservation Temperature and Cryopreservation on European Eel Sperm Fertilization Capacity. Reprod Domest Anim 2016; 51:485-91. [PMID: 27189043 DOI: 10.1111/rda.12706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 04/12/2016] [Indexed: 10/21/2022]
Abstract
Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols. Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few larvae ('cryolarvae') were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success.
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Affiliation(s)
- J F Asturiano
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Valencia, Spain
| | - S R Sørensen
- Technical University of Denmark, National Institute of Aquatic Resources, Charlottenlund, Denmark
| | - L Pérez
- Grupo de Acuicultura y Biodiversidad, Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, Valencia, Spain
| | - P Lauesen
- Billund Aquaculture Service A/S, Billund, Denmark
| | - J Tomkiewicz
- Technical University of Denmark, National Institute of Aquatic Resources, Charlottenlund, Denmark
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