1
|
Lai KP, Boncan DAT, Qin X, Chan TF, Tse WKF. Roles and occurrences of microbiota in the osmoregulatory organs, gills and gut, in marine medaka upon hypotonic stress. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 52:101285. [PMID: 39002350 DOI: 10.1016/j.cbd.2024.101285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/15/2024]
Abstract
Gills and gut are the two primary osmoregulatory organs in fish. Recently, studies have expanded beyond the osmoregulatory mechanisms of these organs to explore the microbiota communities inhabiting them. It is now known that microbial communities in both organs shift in response to osmotic stress. However, there are limited studies identifying the major contributors and co-occurrence among these microbiota in both organs under seawater and freshwater transfer conditions. The current data mining report performed a bioinformatics analysis on two previous published datasets from our group, aiming to provide insights into host-bacteria relationships under osmotic stress. We divided the samples into four groups: control seawater gills (LSW); control seawater gut (TSW); freshwater transfer gills (LFW); and freshwater transfer gut (TFW). Our results showed that LSW had higher diversities, richness, and evenness compared to TSW. However, both the LFW and LSW did not show any significant differences after the freshwater transfer experiment. We further applied co-occurrence network analysis and, for the first time, reported on the interactions of taxa shaping the community structure in these two organs. Moreover, we identified enriched ectoine biosynthesis in seawater samples, suggesting its potential role in seawater environments. Increased mRNA expression levels of Na+/K+-atpase, and cftr, were observed in gills after 6 h of ectoine treatment. These findings provide a foundation for future studies on host-bacteria interactions under osmotic stress.
Collapse
Affiliation(s)
- Keng Po Lai
- Key Laboratory of Environmental Pollution and Integrative Omics, Education Department of Guangxi Zhuang Autonomous Region, Guilin Medical University, China; Department of Chemistry, City University of Hong Kong, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Delbert Almerick T Boncan
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Xian Qin
- Department of Chemistry, City University of Hong Kong, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China
| | - Ting Fung Chan
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - William Ka Fai Tse
- Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
| |
Collapse
|
2
|
Marrero M, Monroig Ó, Pérez JA, Betancor MB, Galindo A, Bolaños A, Acosta NG, Rodríguez C. Dietary LC-PUFA and environmental salinity modulate the fatty acid biosynthesis capacity of the euryhaline teleost thicklip grey mullet (Chelon labrosus). Comp Biochem Physiol B Biochem Mol Biol 2024; 269:110865. [PMID: 37230375 DOI: 10.1016/j.cbpb.2023.110865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 05/27/2023]
Abstract
The capacity to biosynthesise long-chain (≥C20) polyunsaturated fatty acids (LC-PUFA) depends upon the complement and function of key enzymes commonly known as fatty acyl desaturases and elongases. The presence of a Δ5/Δ6 desaturase enabling the biosynthesis of docosahexaenoic acid (22:6n-3, DHA) through the "Sprecher pathway" has been reported in Chelon labrosus. Research in other teleosts have demonstrated that LC-PUFA biosynthesis can be modulated by diet and ambient salinity. The present study aimed to assess the combined effects of partial dietary replacement of fish oil (FO) by vegetable oil (VO) and reduced ambient salinity (35 ppt vs 20 ppt) on the fatty acid composition of muscle, enterocytes and hepatocytes of C. labrosus juveniles. Moreover, the enzymatic activity over radiolabelled [1-14C] 18:3n-3 (α-linolenic acid, ALA) and [1-14C] 20:5n-3 (eicosapentaenoic acid, EPA) to biosynthesise n-3 LC-PUFA in hepatocytes and enterocytes, and the gene regulation of the C. labrosus fatty acid desaturase-2 (fads2) and elongation of very long chain fatty acids protein 5 (elovl5) in liver and intestine was also investigated. Recovery of radiolabelled products including stearidonic acid (18:4n-3, SDA), 20:5n-3, tetracosahexaenoic acid (24:6n-3, THA) and 22:6n-3 in all treatments except FO35-fish, provided compelling evidence that a complete pathway enabling the biosynthesis of EPA and DHA from ALA is present and active in C. labrosus. Low salinity conditions upregulated fads2 in hepatocytes and elovl5 in both cell types, regardless of dietary composition. Interestingly, FO20-fish showed the highest amount of n-3 LC-PUFA in muscle, while no differences in VO-fish reared at both salinities were found. These results demonstrate a compensatory capacity of C. labrosus to biosynthesise n-3 LC-PUFA under reduced dietary supply, and emphasise the potential of low salinity conditions to stimulate this pathway in euryhaline fish.
Collapse
Affiliation(s)
- Manuel Marrero
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain.
| | - Óscar Monroig
- Instituto de Acuicultura Torre de la Sal (IATS), CSIC, 12595 Ribera de Cabanes, Castellón, Spain
| | - José A Pérez
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain
| | - Mónica B Betancor
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Ana Galindo
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain
| | - Ana Bolaños
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain
| | - N Guadalupe Acosta
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain
| | - Covadonga Rodríguez
- Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, 38206 La Laguna, Spain
| |
Collapse
|
3
|
Barany A, Fuentes J, Valderrama V, Broz-Ruiz A, Martínez-Rodríguez G, Mancera JM. Oral cortisol and dexamethasone intake: Differential physiology and transcriptional responses in the marine juvenile Sparus aurata. Gen Comp Endocrinol 2023; 344:114371. [PMID: 37640145 DOI: 10.1016/j.ygcen.2023.114371] [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: 01/20/2023] [Revised: 07/12/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
This study approached the long-term oral administration of cortisol (F) and dexamethasone (DEX), two synthetic glucocorticoids, compared to a control group (CT) in the juveniles of a marine teleost, the gilthead seabream (Sparus aurata). Physiologically, DEX treatment impaired growth, which appears to be linked to carbohydrate allocation in muscle and liver, hepatic triglycerides depletion, and reduced hematocrit. Hypophyseal gh mRNA expression was 2-fold higher in DEX than in CT or F groups. Similarly, hypothalamic trh and hypophyseal pomcb followed this pattern. Plasma cortisol levels were significantly lower in DEX than in CT, while F presented intermediate levels. In the posterior intestine, measured short circuit-current (Isc) was more anion absorptive in CT and F compared to the DEX group, whereas Isc remained unaffected in the anterior intestine. The derived transepithelial electric resistance (TEER) significantly differed between intestinal regions in the DEX group. These results provide new insights to understand better potential targeted biomarkers indicative of the differential glucocorticoid or mineralocorticoid-receptors activation in fish.
Collapse
Affiliation(s)
- A Barany
- Department of Biology, Morrill Science Center, University of Massachusetts, 01003 Amherst, MA, USA; Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, E-11510 Puerto Real, Cádiz, Spain.
| | - J Fuentes
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
| | - V Valderrama
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, E-11510 Puerto Real, Cádiz, Spain
| | - A Broz-Ruiz
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, E-11510 Puerto Real, Cádiz, Spain
| | - G Martínez-Rodríguez
- Instituto de Ciencias Marinas de Andalucía, Spanish National Research Council (ICMAN-CSIC), E-11510 Puerto Real, Cádiz, Spain
| | - J M Mancera
- Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, E-11510 Puerto Real, Cádiz, Spain
| |
Collapse
|
4
|
Acute Stress in Lesser-Spotted Catshark (Scyliorhinus canicula Linnaeus, 1758) Promotes Amino Acid Catabolism and Osmoregulatory Imbalances. Animals (Basel) 2022; 12:ani12091192. [PMID: 35565621 PMCID: PMC9105869 DOI: 10.3390/ani12091192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/27/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Simple Summary In catsharks (Scyliorhinus canicula), air exposure induces amino acid catabolism altogether with osmoregulatory imbalances. This study describes a novel NHE isoform being expressed in gills that may be involved in ammonium excretion. Abstract Acute-stress situations in vertebrates induce a series of physiological responses to cope with the event. While common secondary stress responses include increased catabolism and osmoregulatory imbalances, specific processes depend on the taxa. In this sense, these processes are still largely unknown in ancient vertebrates such as marine elasmobranchs. Thus, we challenged the lesser spotted catshark (Scyliorhinus canicula) to 18 min of air exposure, and monitored their recovery after 0, 5, and 24 h. This study describes amino acid turnover in the liver, white muscle, gills, and rectal gland, and plasma parameters related to energy metabolism and osmoregulatory imbalances. Catsharks rely on white muscle amino acid catabolism to face the energy demand imposed by the stressor, producing NH4+. While some plasma ions (K+, Cl− and Ca2+) increased in concentration after 18 min of air exposure, returning to basal values after 5 h of recovery, Na+ increased after just 5 h of recovery, coinciding with a decrease in plasma NH4+. These changes were accompanied by increased activity of a branchial amiloride-sensitive ATPase. Therefore, we hypothesize that this enzyme may be a Na+/H+ exchanger (NHE) related to NH4+ excretion. The action of an omeprazole-sensitive ATPase, putatively associated to a H+/K+-ATPase (HKA), is also affected by these allostatic processes. Some complementary experiments were carried out to delve a little deeper into the possible branchial enzymes sensitive to amiloride, including in vivo and ex vivo approaches, and partial sequencing of a nhe1 in the gills. This study describes the possible presence of an HKA enzyme in the rectal gland, as well as a NHE in the gills, highlighting the importance of understanding the relationship between acute stress and osmoregulation in elasmobranchs.
Collapse
|
5
|
Takei Y, Ando M, Wong MKS, Tsukada T. Molecular mechanisms underlying guanylin-induced transcellular Cl - secretion into the intestinal lumen of seawater-acclimated eels. Gen Comp Endocrinol 2022; 318:113986. [PMID: 35114197 DOI: 10.1016/j.ygcen.2022.113986] [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: 07/07/2021] [Revised: 12/20/2021] [Accepted: 01/27/2022] [Indexed: 11/19/2022]
Abstract
Guanylin (GN) stimulates Cl- secretion into the intestinal lumen of seawater-acclimated eels, but the molecular mechanisms of transepithelial Cl- transport are still unknown. In Ussing chamber experiments, we confirmed that mucosal application of eel GN reversed intestinal serosa-negative potential difference, indicating Cl- secretion. Serosal application of DNDS or mucosal application of DPC inhibited the GN effect, but serosal application of bumetanide had no effect. Removal of HCO3- from the serosal fluid also inhibited the GN effect. In intestinal sac experiments, mucosal GN stimulated luminal secretion of both Cl- and Na+, which was blocked by serosal DNDS. These results suggest that Cl- is taken up at the serosal side by DNDS-sensitive anion exchanger (AE) coupled with Na+-HCO3- cotransporter (NBC) but not by Na+-K+-2Cl- cotransporter 1 (NKCC1), and Cl- is secreted by unknown DPC-sensitive Cl- channel (ClC) at the mucosal side. The transcriptomic analysis combined with qPCR showed low expression of NKCC1 gene and no upregulation of the gene after seawater transfer, while high expression of ClC2 gene and upregulation after seawater transfer. In addition, SO42- transporters (apical Slc26a3/6 and basolateral Slc26a1) are also candidates for transcellular Cl- secretion in exchange of luminal SO42. Na+ secretion could occur through a paracellular route, as Na+-leaky claudin15 was highly expressed and upregulated after seawater transfer. High local Na+ concentration in the lateral interspace produced by Na+/K+-ATPase (NKA) coupled with K+ channels (Kir5.1b) seems to facilitate the paracellular transport. In situ hybridization confirmed the expression of the candidate genes in the epithelial enterocytes. Together with our previous results, we suggest that GN stimulates basolateral NBCela/AE2 and apical ClC2 to increase transcellular Cl- secretion in seawater eel intestine, which differs from the involvement of apical CFTR and basolateral NKCC1 as suggested in mammals and other teleosts.
Collapse
Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
| | - Masaaki Ando
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Marty K S Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Takehiro Tsukada
- Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Chiba 274-8510, Japan
| |
Collapse
|
6
|
Barany A, Oliva M, Gregório SF, Martínez-Rodríguez G, Mancera JM, Fuentes J. Dysregulation of Intestinal Physiology by Aflatoxicosis in the Gilthead Seabream ( Sparus aurata). Front Physiol 2022; 12:741192. [PMID: 34987413 PMCID: PMC8722709 DOI: 10.3389/fphys.2021.741192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/22/2021] [Indexed: 12/11/2022] Open
Abstract
Aflatoxin B1 (AFB1) is a mycotoxin often present in food. This study aimed to understand the physiological effects of AFB1 on the seabream (Sparus aurata) gastrointestinal system. In a first in vitro approach, we investigated ion transport using the short-circuit current (Isc) technique in Ussing chambers in the anterior intestine (AI). Application of apical/luminal AFB1 concentrations of 8 and 16 μM to healthy tissues was without effect on tissue transepithelial electrical resistance (TER), and apparent tissue permeability (Papp) was measured using fluorescein FITC (4 kD). However, it resulted in dose-related effects on Isc. In a second approach, seabream juveniles fed with different AFB1 concentrations (1 and 2 mg AFB1 kg−1 fish feed) for 85 days showed significantly reduced gill Na+/K+-ATPase (NKA) and H+-ATPase (HA) activities in the posterior intestine (PI). Moreover, dietary AFB1 modified Isc in the AI and PI, significantly affecting TER in the AI. To understand this effect on TER, we analyzed the expression of nine claudins and three occludins as markers of intestinal architecture and permeability using qPCR. Around 80% of the genes presented significantly different relative mRNA expression between AI and PI and had concomitant sensitivity to dietary AFB1. Based on the results of our in vitro, in vivo, and molecular approaches, we conclude that the effects of dietary AFB1 in the gastrointestinal system are at the base of the previously reported growth impairment caused by AFB1 in fish.
Collapse
Affiliation(s)
- Andre Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Cádiz, Spain
| | - Milagrosa Oliva
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Cádiz, Spain
| | - Silvia Filipa Gregório
- Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| | - Gonzalo Martínez-Rodríguez
- Instituto de Ciencias Marinas de Andalucía, Consejo Superior de Investigaciones Científicas (ICMAN-CSIC), Cádiz, Spain
| | - Juan Miguel Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Cádiz, Spain
| | - Juan Fuentes
- Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, Faro, Portugal
| |
Collapse
|
7
|
Barany A, Shaughnessy CA, Pelis RM, Fuentes J, Mancera JM, McCormick SD. Tissue and salinity specific Na +/Cl - cotransporter (NCC) orthologues involved in the adaptive osmoregulation of sea lamprey (Petromyzon marinus). Sci Rep 2021; 11:22698. [PMID: 34811419 PMCID: PMC8608846 DOI: 10.1038/s41598-021-02125-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/29/2021] [Indexed: 12/12/2022] Open
Abstract
Two orthologues of the gene encoding the Na+-Cl− cotransporter (NCC), termed ncca and nccb, were found in the sea lamprey genome. No gene encoding the Na+-K+-2Cl− cotransporter 2 (nkcc2) was identified. In a phylogenetic comparison among other vertebrate NCC and NKCC sequences, the sea lamprey NCCs occupied basal positions within the NCC clades. In freshwater, ncca mRNA was found only in the gill and nccb only in the intestine, whereas both were found in the kidney. Intestinal nccb mRNA levels increased during late metamorphosis coincident with salinity tolerance. Acclimation to seawater increased nccb mRNA levels in the intestine and kidney. Electrophysiological analysis of intestinal tissue ex vivo showed this tissue was anion absorptive. After seawater acclimation, the proximal intestine became less anion absorptive, whereas the distal intestine remained unchanged. Luminal application of indapamide (an NCC inhibitor) resulted in 73% and 30% inhibition of short-circuit current (Isc) in the proximal and distal intestine, respectively. Luminal application of bumetanide (an NKCC inhibitor) did not affect intestinal Isc. Indapamide also inhibited intestinal water absorption. Our results indicate that NCCb is likely the key ion cotransport protein for ion uptake by the lamprey intestine that facilitates water absorption in seawater. As such, the preparatory increases in intestinal nccb mRNA levels during metamorphosis of sea lamprey are likely critical to development of whole animal salinity tolerance.
Collapse
Affiliation(s)
- A Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar (CEI-MAR), University of Cádiz, Puerto Real, 11519, Cádiz, Spain. .,Centre of Marine Sciences (CCMar), University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal. .,Conte Anadromous Fish Research Laboratory, Eastern Ecological Science Center, U.S. Geological Survey, Turners Falls, MA, 01376, USA.
| | - C A Shaughnessy
- Conte Anadromous Fish Research Laboratory, Eastern Ecological Science Center, U.S. Geological Survey, Turners Falls, MA, 01376, USA.,Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - R M Pelis
- Department of Pharmaceutical Sciences, Binghamton University, State University of New York, Johnson City, NY, 13790, USA
| | - J Fuentes
- Centre of Marine Sciences (CCMar), University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - J M Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar (CEI-MAR), University of Cádiz, Puerto Real, 11519, Cádiz, Spain
| | - S D McCormick
- Conte Anadromous Fish Research Laboratory, Eastern Ecological Science Center, U.S. Geological Survey, Turners Falls, MA, 01376, USA.,Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA
| |
Collapse
|
8
|
Barany A, Gilannejad N, Alameda-López M, Rodríguez-Velásquez L, Astola A, Martínez-Rodríguez G, Roo J, Muñoz JL, Mancera JM. Osmoregulatory Plasticity of Juvenile Greater Amberjack ( Seriola dumerili) to Environmental Salinity. Animals (Basel) 2021; 11:2607. [PMID: 34573573 PMCID: PMC8465821 DOI: 10.3390/ani11092607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/23/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
Osmotic costs in teleosts are highly variable, reaching up to 50% of energy expenditure in some. In several species, environmental salinities close to the isosmotic point (~15 psu) minimize energy demand for osmoregulation while enhancing growth. The present study aimed to characterize the physiological status related to osmoregulation in early juveniles of the greater amberjack, Seriola dumerili, acclimated to three salinities (15, 22, and 36 psu). Our results indicate that plasma metabolic substrates were enhanced at the lower salinities, whereas hepatic carbohydrate and energetic lipid substrates decreased. Moreover, osmoregulatory parameters, such as osmolality, muscle water content, gill and intestine Na+-K+-ATPase activities, suggested a great osmoregulatory capacity in this species. Remarkably, electrophysiological parameters, such as short-circuit current (Isc) and transepithelial electric resistance (TER), were enhanced significantly at the posterior intestine. Concomitantly, Isc and TER anterior-to-posterior intestine differences were intensified with increasing environmental salinity. Furthermore, the expression of several adeno-hypophyseal genes was assessed. Expression of prl showed an inverse linear relationship with increasing environmental salinity, while gh mRNA enhanced significantly in the 22 psu-acclimated groups. Overall, these results could explain the better growth observed in S. dumerili juveniles kept at salinities close to isosmotic rather than in seawater.
Collapse
Affiliation(s)
- Andre Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Puerto Real, E11510 Cádiz, Spain; (M.A.-L.); (L.R.-V.); (J.M.M.)
| | - Neda Gilannejad
- Instituto de Ciencias Marinas de Andalucía, Consejo Superior de Investigaciones Científicas (ICMAN-CSIC), Puerto Real, E11519 Cádiz, Spain; (N.G.); (G.M.-R.)
- NORCE Norwegian Research Centre AS, Uni Research Environment, Nygårdsgaten 112, E5008 Bergen, Norway
| | - María Alameda-López
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Puerto Real, E11510 Cádiz, Spain; (M.A.-L.); (L.R.-V.); (J.M.M.)
| | - Liliana Rodríguez-Velásquez
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Puerto Real, E11510 Cádiz, Spain; (M.A.-L.); (L.R.-V.); (J.M.M.)
| | - Antonio Astola
- Department of Biomedicine, Biotechnology, and Public Health, Faculty of Sciences, Campus de Excelencia Internacional del Mar (CEI-MAR), University of Cadiz, Puerto Real, E11510 Cádiz, Spain;
| | - Gonzalo Martínez-Rodríguez
- Instituto de Ciencias Marinas de Andalucía, Consejo Superior de Investigaciones Científicas (ICMAN-CSIC), Puerto Real, E11519 Cádiz, Spain; (N.G.); (G.M.-R.)
| | - Javier Roo
- Grupo de Investigación en Acuicultura (GIA), Instituto Universitario Ecoaqua, Universidad de Las Palmas de Gran Canaria, Crta. Taliarte s/n, E35214 Gran Canaria, Spain;
| | - Jose Luis Muñoz
- Department of Production, IFAPA Centro “El Toruño”, Junta de Andalucía, El Puerto de Santa María, E11500 Cádiz, Spain;
| | - Juan Miguel Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), University of Cádiz, Puerto Real, E11510 Cádiz, Spain; (M.A.-L.); (L.R.-V.); (J.M.M.)
| |
Collapse
|
9
|
Ruiz-Jarabo I, Gregório SF, Alves A, Mancera JM, Fuentes J. Ocean acidification compromises energy management in Sparus aurata (Pisces: Teleostei). Comp Biochem Physiol A Mol Integr Physiol 2021; 256:110911. [PMID: 33647459 DOI: 10.1016/j.cbpa.2021.110911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/18/2021] [Accepted: 01/18/2021] [Indexed: 11/19/2022]
Abstract
The effects of ocean acidification mediated by an increase in water pCO2 levels on marine organisms are currently under debate. Elevated CO2 concentrations in the seawater induce several physiological responses in teleost fish, including acid-base imbalances and osmoregulatory changes. However, the consequences of CO2 levels enhancement on energy metabolism are mostly unknown. Here we show that 5 weeks of exposure to hypercapnia (950 and 1800 μatm CO2) altered intermediary metabolism of gilthead seabream (Sparus aurata) compared to fish acclimated to current ocean values (440 μatm CO2). We found that seabream compromises its physiological acid-base balance with increasing water CO2 levels and the subsequent acidification. Intestinal regions (anterior, mid, and rectum) engaged in maintaining this balance are thus altered, as seen for Na+/K+-ATPase and the vacuolar-type H+-ATPase activities. Moreover, liver and muscle counteracted these effects by increasing catabolic routes e.g., glycogenolysis, glycolysis, amino acid turnover, and lipid catabolism, and plasma energy metabolites were altered. Our results demonstrate how a relatively short period of 5 weeks of water hypercapnia is likely to disrupt the acid-base balance, osmoregulatory capacity and intermediary metabolism in S. aurata. However, long-term studies are necessary to fully understand the consequences of ocean acidification on growth and other energy-demanding activities, such as reproduction.
Collapse
Affiliation(s)
- I Ruiz-Jarabo
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal; Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Cádiz, Spain; Department of Animal Physiology, Faculty of Biological Sciences, University Complutense, Madrid, Spain.
| | - S F Gregório
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal
| | - A Alves
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal
| | - J M Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Cádiz, Spain
| | - J Fuentes
- Centre of Marine Sciences (CCMar), University do Algarve, Campus de Gambelas, Faro, Portugal.
| |
Collapse
|
10
|
Lin G, Zheng M, Li S, Xie J, Fang W, Gao D, Huang J, Lu J. Response of gut microbiota and immune function to hypoosmotic stress in the yellowfin seabream (Acanthopagrus latus). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 745:140976. [PMID: 32736105 DOI: 10.1016/j.scitotenv.2020.140976] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/09/2020] [Accepted: 07/12/2020] [Indexed: 06/11/2023]
Abstract
Osmotic stress is associated with heightened immune functions and altered microbiota in the fish intestine. In this study, we explored the effects of hypoosmotic stress on the intestine of euryhaline yellowfin seabream (Acanthopagrus latus) after acute exposure to brackish water, low-saline water, and freshwater environments. The results showed that hypoosmotic stress reshaped the composition of the microbial community and altered the gene expression in the intestine. Probiotics Lactobacillus and Pseudomonas showed higher relative abundance in a brackish water environment, whereas pathogenic bacteria, including Vibrio and Aeromonas, were more abundant in the freshwater environment. At the transcriptional level, osmoregulation-related genes were identified as up/down regulated differentially expressed genes (DEGs) as well as a series of immune-related DEGs associated with pathogen recognition, antimicrobial ability, pro-inflammatory cytokines, cell apoptosis, and antioxidant defense. Physiological analysis showed that Na+ K+-ATPase activity was significantly inhibited by hypoosmotic stress in freshwater. Meanwhile, the intestinal antioxidant defense system of yellowfin seabream was challenged. Correlation network analysis demonstrated the close interactions among intestinal microbes, differentially expressed genes, and physiological parameters. This study provides the critical insights into the function of the intestine fish encountering hypoosmotic stress.
Collapse
Affiliation(s)
- Genmei Lin
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Min Zheng
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Shizhu Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Jingui Xie
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Wenyu Fang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Dong Gao
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Jing Huang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Jianguo Lu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China.
| |
Collapse
|
11
|
Barany A, Shaughnessy CA, Fuentes J, Mancera JM, McCormick SD. Osmoregulatory role of the intestine in the sea lamprey ( Petromyzon marinus). Am J Physiol Regul Integr Comp Physiol 2019; 318:R410-R417. [PMID: 31747320 DOI: 10.1152/ajpregu.00033.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Lampreys are the most basal vertebrates with an osmoregulatory strategy. Previous research has established that the salinity tolerance of sea lamprey increases dramatically during metamorphosis, but underlying changes in the gut have not been examined. In the present work, we examined changes in intestinal function during metamorphosis and seawater exposure of sea lamprey (Petromyzon marinus). Fully metamorphosed juvenile sea lamprey had 100% survival after direct exposure to 35 parts per thousand seawater (SW) and only slight elevations in plasma chloride (Cl-) levels. Drinking rates of sea lamprey juveniles in seawater were 26-fold higher than juveniles in freshwater (FW). Na+-K+-ATPase (NKA) activity in the anterior and posterior intestine increased 12- and 3-fold, respectively, during metamorphosis, whereas esophageal NKA activity was lower than in the intestine and did not change with development. Acclimation to SW significantly enhanced NKA activity in the posterior intestine but did not significantly change NKA activity in the anterior intestine, which remained higher than that in the posterior intestine. Intestinal Cl- and water uptake, which were observed in ex vivo preparations of anterior and posterior intestine under both symmetric and asymmetric conditions, were higher in juveniles than in larvae and were similar in magnitude of those of teleost fish. Inhibition of NKA by ouabain in ex vivo preparations inhibited intestinal water absorption by 64%. Our results indicate drinking and intestinal ion and water absorption are important to osmoregulation in SW and that preparatory increases in intestinal NKA activity are important to the development of salinity tolerance that occurs during sea lamprey metamorphosis.
Collapse
Affiliation(s)
- A Barany
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar, University of Cádiz, Cádiz, Spain.,Centre of Marine Sciences, University of Algarve, Gambelas, Faro, Portugal
| | - C A Shaughnessy
- United States Geological Survey, Leetown Science Center, S.O. Conte Anadromous Fish Research Laboratory, Turners Falls, Massachusetts
| | - J Fuentes
- Centre of Marine Sciences, University of Algarve, Gambelas, Faro, Portugal
| | - J M Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Campus de Excelencia Internacional del Mar, University of Cádiz, Cádiz, Spain
| | - S D McCormick
- United States Geological Survey, Leetown Science Center, S.O. Conte Anadromous Fish Research Laboratory, Turners Falls, Massachusetts.,Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts
| |
Collapse
|
12
|
Zhang X, Wen H, Qi X, Zhang K, Liu Y, Fan H, Yu P, Tian Y, Li Y. Na+-K+-ATPase and nka genes in spotted sea bass (Lateolabrax maculatus) and their involvement in salinity adaptation. Comp Biochem Physiol A Mol Integr Physiol 2019; 235:69-81. [DOI: 10.1016/j.cbpa.2019.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 11/28/2022]
|
13
|
Jerez-Cepa I, Fernández-Castro M, Del Santo O'Neill TJ, Martos-Sitcha JA, Martínez-Rodríguez G, Mancera JM, Ruiz-Jarabo I. Transport and Recovery of Gilthead Seabream ( Sparus aurata L.) Sedated With Clove Oil and MS-222: Effects on Stress Axis Regulation and Intermediary Metabolism. Front Physiol 2019; 10:612. [PMID: 31214040 PMCID: PMC6555194 DOI: 10.3389/fphys.2019.00612] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/01/2019] [Indexed: 11/13/2022] Open
Abstract
Transport processes between aquaculture facilities activate the stress response in fish. To deal with these situations, the hypothalamic-pituitary-interrenal (HPI) axis releases cortisol, leading to an increase in circulating energy resources to restore homeostasis. However, if the allostatic load generated exceeds fish tolerance limits, stress-related responses will compromise health and welfare of the animals. In this context, anesthetics have arisen as potential agents aiming to reduce negative effects of stress response. Here we assessed the effects of a sedative dose of clove oil (CO) and MS-222 on hallmarks involved in HPI axis regulation and energy management after simulated transport, and further recovery, in gilthead seabream (Sparus aurata L.) juveniles. Fish were placed in a mobile setup of water tanks where transport conditions were simulated for 6 h. Sedation doses of either CO (2.5 mg L−1) or MS-222 (5 mg L−1) were added in the water tanks. A control group without anesthetics was also included in the setup. Half of the animals (n = 12 per group) were sampled immediately after transport, while remaining animals were allowed to recover for 18 h in clean water tanks and then sampled. Our results showed that the HPI axis response was modified at peripheral level, with differences depending on the anesthetic employed. Head kidney gene-expressions related to cortisol production (star and cyp11b1) matched concomitantly with increased plasma cortisol levels immediately after transport in CO-sedated fish, but these levels remained constant in MS-222-sedated fish. Differential changes in the energy management of carbohydrates, lipids and amino acids, depending on the anesthetic employed, were also observed. The use of CO stimulated amino acids catabolism, while MS-222-sedated fish tended to consume liver glycogen and mobilize triglycerides. Further studies, including alternative doses of both anestethics, as well as the assessment of time-course HPI activation and longer recovery periods, are necessary to better understand if the use of clove oil and MS-222 is beneficial for S. aurata under these circumstances.
Collapse
Affiliation(s)
- Ismael Jerez-Cepa
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| | - Miriam Fernández-Castro
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| | - Thomas Julian Del Santo O'Neill
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| | - Juan Antonio Martos-Sitcha
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| | - Gonzalo Martínez-Rodríguez
- Department of Marine Biology and Aquaculture, Institute of Marine Sciences of Andalusia (ICMAN), Spanish National Research Council (CSIC), Puerto Real, Spain
| | - Juan Miguel Mancera
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| | - Ignacio Ruiz-Jarabo
- Department of Biology, Faculty of Marine and Environmental Sciences, Instituto Universitario de Investigación Marina (INMAR), Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Puerto Real, Spain
| |
Collapse
|
14
|
Alves A, Gregório SF, Egger RC, Fuentes J. Molecular and functional regionalization of bicarbonate secretion cascade in the intestine of the European sea bass (Dicentrarchus labrax). Comp Biochem Physiol A Mol Integr Physiol 2019; 233:53-64. [PMID: 30946979 DOI: 10.1016/j.cbpa.2019.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/20/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
In marine fish the intestinal HCO3- secretion is the key mechanism to enable luminal aggregate formation and water absorption. Using the sea bass (Dicentrarchus labrax), the present study aimed at establishing the functional and molecular organization of different sections of the intestine concerning bicarbonate secretion and Cl- movements. The proximal intestinal regions presented similar HCO3- secretion rates, while differences were detected in the molecular expression of the transporters involved and on regional HCO3- concentrations. The anterior region presented significantly higher Na+/K+-ATPase activity, Cl- transepithelial transport and basolateral slc4a4, apical slc26a6 and slc26a3 expression levels. In the mid intestine, the total HCO3- content was significantly increased in the fluid as in the carbonate aggregates. In the rectum no HCO3- secretion was observed and was characterized by the diminished HCO3- total content, residual molecular expression of slc4a4, slc26a6 and slc26a3, higher H+-ATPase activity and expression, suggesting the existence of a different bicarbonate handling mechanism. The possible regulation of HCO3- secretion by extracellular HCO3- and increased intracellular cAMP levels were also investigated. cAMP did not affect HCO3- secretion, although Cl- secretion was enhanced by cftr. HCO3- secretion rise due to the HCO3- basolateral increment showed that at resting levels slc4a4 was not a limiting step for secretion. The transcellular/intracellular dependence of apical HCO3- secretion differed between the proximal regions. In conclusion, intestinal HCO3- secretion has a functional region-dependent organization that was not reflected by the anterior-posterior regionalization on HCO3- secretion and expression profiles of chloride/water absorption related genes.
Collapse
Affiliation(s)
- Alexandra Alves
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Sílvia F Gregório
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Renata C Egger
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Juan Fuentes
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| |
Collapse
|
15
|
Environmental Salinity Affects Growth and Metabolism in Fingerling Meagre (Argyrosomus Regius). FISHES 2019. [DOI: 10.3390/fishes4010006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The meagre (Argyrosomus regius), a farmed fish in Mediterranean countries, seasonally migrates from offshore areas to estuaries for reproduction. During the first two years of life, the meagre evidences a certain grade of euryhalinity by staying in brackish waters close to the shore. The aim of the present study was to establish if fingerling growth in brackish water is improved compared to seawater, where current culture procedures are conducted. Three-month-old fingerlings were maintained for 45 days under two different salinity regimens (12 and 39 ppt). Several growth parameters as well as osmoregulatory and metabolic variables were assessed. Specific growth rate and hepatosomatic index values revealed that fingerlings performed better in brackish waters (12 ppt) compared to 39 ppt. This study contributes to optimizing meagre rearing conditions, thereby supporting the role of A. regius in aquaculture diversification.
Collapse
|
16
|
Narrowing the Range of Environmental Salinities Where Juvenile Meagre (Argyrosomus regius) Can Be Cultured Based on an Osmoregulatory Pilot Study. FISHES 2018. [DOI: 10.3390/fishes3040048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Aquaculture in Europe aims to diversify and optimize fish farming. The meagre (Argyrosomus regius) arose as a promising species due to its fast growth rates and flesh quality. Thus, it is currently being produced in several Mediterranean countries, mainly in sea-cages and salt-marshes. However, although meagre naturally spend the first years of life in brackish waters, to date it is cultured in seawater. Here, we show that juveniles may not successfully face either freshwater or hyper-osmotic environments as high as 55 ppt salinity. We found that 55 ppt induced catabolism and mobilization of energy metabolites stored in the liver, probably to maintain its osmotic balance. Furthermore, we found that osmoregulatory tissues such as gills managed to maintain plasma osmolality levels without differences in meagre acclimated at 5, 12 and 39 ppt salinity. Our results demonstrate the euryhaline capacity of this species, highlighting that juveniles may be cultured in a wider range of salinities rather than just at seawater. Future studies should focus on optimal environmental salinities for the growth of A. regius juveniles, including long-term experiments limited to the range of 5 ppt to full-strength seawater. Minimizing fish energy consumption in osmoregulation could be economically beneficial for the aquaculture industry in Europe.
Collapse
|
17
|
Interrogation of the Gulf toadfish intestinal proteome response to hypersalinity exposure provides insights into osmoregulatory mechanisms and regulation of carbonate mineral precipitation. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2018; 27:66-76. [DOI: 10.1016/j.cbd.2018.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/11/2018] [Accepted: 06/18/2018] [Indexed: 12/26/2022]
|
18
|
Ruiz-Jarabo I, Gregório SF, Gaetano P, Trischitta F, Fuentes J. High rates of intestinal bicarbonate secretion in seawater tilapia (Oreochromis mossambicus). Comp Biochem Physiol A Mol Integr Physiol 2017; 207:57-64. [PMID: 28238831 DOI: 10.1016/j.cbpa.2017.02.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/13/2017] [Accepted: 02/20/2017] [Indexed: 01/07/2023]
Abstract
Osmoregulation in fish is a complex process that requires the orchestrated cooperation of many tissues. In fish facing hyperosmotic environments, the intestinal absorption of some monovalent ions and the secretion of bicarbonate are key processes to favor water absorption. In the present study, we showed that bicarbonate levels in the intestinal fluid are several fold higher in seawater than in freshwater acclimated tilapia (Oreochromis mossambicus). In addition, we analyzed gene expression of the main molecular mechanisms involved in HCO3- movements i.e. slc26a6, slc26a3, slc4a4 and v-type H-ATPase sub C in the intestine of tilapia acclimated to both seawater and freshwater. Our results show an anterior/posterior functional regionalization of the intestine in tilapia in terms of expression patterns, which is affected by environmental salinity mostly in the anterior and mid intestine. Analysis of bicarbonate secretion using pH-Stat in tissues mounted in Ussing chambers reveals high rates of bicarbonate secretion in tilapia acclimated to seawater from anterior intestine to rectum ranging between ~900 and ~1700nmolHCO3-cm-2h-1. However, a relationship between the expression of slc26a6, slc26a3, slc4a4 and the rate of bicarbonate secretion seems to be compromised in the rectum. In this region, the low expression of the bicarbonate transporters could not explain the high bicarbonate secretion rates here described. However, we postulate that the elevated v-type H-ATPase mRNA expression in the rectum could be involved in this process.
Collapse
Affiliation(s)
- I Ruiz-Jarabo
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - S F Gregório
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - P Gaetano
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Messina, Italy
| | - F Trischitta
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Messina, Italy
| | - J Fuentes
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences (CCMar), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| |
Collapse
|