1
|
Bucking C, Bury NR, Sundh H, Wood CM. Making in vitro conditions more reflective of in vivo conditions for research on the teleost gastrointestinal tract. J Exp Biol 2024; 227:jeb246440. [PMID: 39392112 DOI: 10.1242/jeb.246440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
To date, the majority of in vitro or ex vivo fish gastrointestinal research has been conducted under unrealistic conditions. In a living fish, ionic conditions, as well as levels of ammonia, pH, HCO3- and PCO2 differ considerably between the different regions of the gastrointestinal tract. These factors also differ from those of the saline often used in gut research. Furthermore, the oxygen gradient from the serosa to the gut lumen is rarely considered: in contrast to the serosa, the lumen is a hypoxic/anoxic environment. In addition, the gut microbiome plays a significant role in gut physiology, increasing the complexity of the in vivo gut, but replicating the microbial community for in vitro studies is exceptionally difficult. However, there are ways in which we can begin to overcome these challenges. Firstly, the luminal chemistry and PO2 in each gut compartment must be carefully considered. Secondly, although microbiological culture techniques are improving, we must learn how to maintain the microbiome diversity seen in vivo. Finally, for ex vivo studies, developing mucosal (luminal) solutions that more closely mimic the in vivo conditions will better replicate physiological processes. Within the field of mammalian gut physiology, great advances in 'gut-on-chip' devices are providing the tools to better replicate in vivo conditions; adopting and adapting this technology may assist in fish gut research initiatives. This Commentary aims to make fish gut physiologists aware of the various issues in replicating the in vivo conditions and identifies solutions as well as those areas that require further improvement.
Collapse
Affiliation(s)
- Carol Bucking
- Department of Biology, Farquharson Life Science Building, York University, Toronto, ON, M3J 1P3, Canada
| | - Nic R Bury
- School of Ocean and Earth Sciences, University of Southampton, National Oceanographic Centre, Waterfront Campus, Southampton, Hampshire, SO14 3ZH, UK
| | - Henrik Sundh
- Department of Biological & Environmental Sciences, University of Gothenburg, Medicinaregatan 7 B, 41390 Göteborg, Sweden
| | - Chris M Wood
- Department of Zoology, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T1Z4, Canada
| |
Collapse
|
2
|
Mes W, Lücker S, Jetten MSM, Siepel H, Gorissen M, van Kessel MAHJ. Feeding strategy and feed protein level affect the gut microbiota of common carp (Cyprinus carpio). ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13262. [PMID: 38725141 PMCID: PMC11082430 DOI: 10.1111/1758-2229.13262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/06/2024] [Indexed: 05/13/2024]
Abstract
Common carp (Cyprinus carpio) were fed food with different protein concentrations following different feeding regimes, which were previously shown to affect growth, nitrogen excretion and amino acid catabolism. 16S rRNA gene amplicon sequencing was performed to investigate the gut microbiota of these fish. Lower dietary protein content increased microbial richness, while the combination of demand feeding and dietary protein content affected the composition of the gut microbiota. Hepatic glutamate dehydrogenase (GDH) activity was correlated to the composition of the gut microbiota in all dietary treatments. We found that demand-fed carp fed a diet containing 39% protein had a significantly higher abundance of Beijerinckiaceae compared to other dietary groups. Network analysis identified this family and two Rhizobiales families as hubs in the microbial association network. In demand-fed carp, the microbial association network had significantly fewer connections than in batch-fed carp. In contrast to the large effects of the feeding regime and protein content of the food on growth and nitrogen metabolism, it had only limited effects on gut microbiota composition. However, correlations between gut microbiota composition and liver GDH activity showed that host physiology and gut microbiota are connected, which warrants functional studies into the role of the gut microbiota in fish physiology.
Collapse
Affiliation(s)
- Wouter Mes
- Department of Microbiology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
- Department of Plant and Animal Biology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| | - Sebastian Lücker
- Department of Microbiology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| | - Mike S. M. Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| | - Henk Siepel
- Department of Plant and Animal Biology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| | - Marnix Gorissen
- Department of Plant and Animal Biology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| | - Maartje A. H. J. van Kessel
- Department of Microbiology, Radboud Institute for Biological and Environmental SciencesRadboud UniversityNijmegenThe Netherlands
| |
Collapse
|
3
|
Mohamad S, Rahmah S, Zainuddin RA, A Thallib Y, Razali RS, Jalilah M, Abd Ghaffar M, Lim LS, Chang YM, Qun Liang L, Das SK, Chen YM, Liew HJ. Hoven's carp Leptobarbus hoevenii strategized metabolism needs to cope with changing environment. Heliyon 2024; 10:e25559. [PMID: 38404778 PMCID: PMC10884815 DOI: 10.1016/j.heliyon.2024.e25559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/27/2024] Open
Abstract
Current water warming and freshwater acidification undoubtedly affect the life of aquatic animals especially ammonotelic teleost by altering their physiological responses. The effect of temperature (28 °C vs 32 °C) and pH (7 vs. 5) on the metabolic compromising strategies of Hoven's carp (Leptobarbus hoevenii) was investigated in this study. Fishes were conditioned to (i) 28 °C + pH 7 (N28°C); (ii) 32 °C + pH 7 (N32°C); (iii) 28 °C + pH 5 (L28°C) and (iv) 32 °C + pH 5 (L32°C) for 20 days followed by osmorespiration assay. Results showed that feeding performance of Hoven's carp was significantly depressed when exposed to low pH conditions (L28°C and L32°C). However, by exposed Hoven's carp to L32°C induced high metabolic oxygen intake and ammonia excretion to about 2x-folds higher compared to the control group. As for energy mobilization, Hoven's carp mobilized liver and muscle protein under L28°C condition. Whereas under high temperature in both pH, Hoven's carp had the tendency to reserve energy in both of liver and muscle. The findings of this study revealed that Hoven's carp is sensitive to lower water pH and high temperature, thereby they remodeled their physiological needs to cope with the environmental changes condition.
Collapse
Affiliation(s)
- Suhaini Mohamad
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Sharifah Rahmah
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
- Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Rabiatul Adawiyyah Zainuddin
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Yusnita A Thallib
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Ros Suhaida Razali
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Mohamad Jalilah
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Mazlan Abd Ghaffar
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
- Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Leong-Seng Lim
- Borneo Marine Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Yu Mei Chang
- Heilongjiang Province's Key Laboratory of Fish Stress Resistance Breeding and Germplasm Characteristics on Special Habitats, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Science, Harbin, China
| | - Li Qun Liang
- Heilongjiang Province's Key Laboratory of Fish Stress Resistance Breeding and Germplasm Characteristics on Special Habitats, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Science, Harbin, China
| | - Simon Kumar Das
- Department of Earth Sciences and Environment, Faculty of Science and Technology, National University of Malaysia, 43600, UKM Bangi, Selangor, Malaysia
- Marine Ecosystem Research Centre, Faculty of Science and Technology, National University of Malaysia, 43600, UKM Bangi, Selangor, Malaysia
| | - Young-Mao Chen
- Marine Biotechnology, College of Life Sciences, National Taiwan Ocean University, Keelung, Taiwan
- Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | - Hon Jung Liew
- Higher Institution Center of Excellence (HICOE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
- Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
- Heilongjiang Province's Key Laboratory of Fish Stress Resistance Breeding and Germplasm Characteristics on Special Habitats, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Science, Harbin, China
| |
Collapse
|
4
|
Wood CM, Wang J, Jung EH, Pelster B. The physiological consequences of a very large natural meal in a voracious marine fish, the staghorn sculpin (Leptocottus armatus). J Exp Biol 2023; 226:jeb246034. [PMID: 37675481 DOI: 10.1242/jeb.246034] [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: 04/29/2023] [Accepted: 08/26/2023] [Indexed: 09/08/2023]
Abstract
Little information exists on physiological consequences when wild fish eat natural food. Staghorn sculpins at 10-13°C voluntarily consumed 15.8% of their body mass in anchovies. Gastric clearance was slow with >60% of the meal retained in the stomach at 48 h, and was not complete until 84 h. At 14-24 h post-feeding, pH was depressed by 3 units and Cl- concentration was elevated 2-fold in gastric chyme, reflecting HCl secretion, while in all sections of the intestine, pH declined by 1 pH unit but Cl- concentration remained unchanged. PCO2 and total ammonia concentration were greatly elevated throughout the tract, whereas PNH3 and HCO3- concentration were depressed. Intestinal HCO3- secretion rates, measured in gut sacs in vitro, were also lower in fed fish. Whole-animal O2 consumption rate was elevated approximately 2-fold for 72 h post-feeding, reflecting 'specific dynamic action', whereas ammonia and urea-N excretion rates were elevated about 5-fold. Arterial blood exhibited a modest 'alkaline tide' for about 48 h, but there was negligible excretion of metabolic base to the external seawater. PaCO2 and PaO2 remained unchanged. Plasma total amino acid concentration and total lipid concentration were elevated about 1.5-fold for at least 48 h, whereas small increases in plasma total ammonia concentration, PNH3 and urea-N concentration were quickly attenuated. Plasma glucose concentration remained unchanged. We conclude that despite the very large meal, slow processing with high efficiency minimizes internal physiological disturbances. This differs greatly from the picture provided by previous studies on aquacultured species using synthetic diets and/or force-feeding. Questions remain about the role of the gastro-intestinal microbiome in nitrogen and acid-base metabolism.
Collapse
Affiliation(s)
- Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada, V0R 1B0
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| | - Jun Wang
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada, V0R 1B0
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
| | - Ellen H Jung
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada, V0R 1B0
| | - Bernd Pelster
- Bamfield Marine Sciences Centre, Bamfield, BC, Canada, V0R 1B0
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center for Molecular Biosciences, University Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
5
|
Jung EH, Nguyen J, Nelson C, Brauner CJ, Wood CM. Ammonia transport is independent of PNH 3 gradients across the gastrointestinal epithelia of the rainbow trout: A role for the stomach. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:180-192. [PMID: 36369634 DOI: 10.1002/jez.2670] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022]
Abstract
Although the gastrointestinal tract (GIT) is an important site for nitrogen metabolism in teleosts, the mechanisms of ammonia absorption and transport remain to be elucidated. Both protein catabolism in the lumen and the metabolism of the GIT tissues produce ammonia which, in part, enters the portal blood through the anterior region of the GIT. The present study examined the possible roles of different GIT sections of rainbow trout (Oncorhynchus mykiss) in transporting ammonia in its unionized gas form-NH3 -by changing the PNH3 gradient across GIT epithelia using in vitro gut sac preparations. We also surveyed messenger RNA expression patterns of three of the identified Rh proteins (Rhbg, Rhcg1, and Rhcg2) as potential NH3 transporters and NKCC as a potential ammonium ion (NH4 + ) transporter along the GIT of rainbow trout. We found that ammonia absorption is not dependent on the PNH3 gradient despite expression of Rhbg and Rhcg2 in the intestinal tissues, and Rhcg2 in the stomach. We detected no expression of Rhbg in the stomach and no expression of Rhcg1 in any GIT tissues. There was also a lack of correlation between ammonia transport and [NH4 + ] gradient despite NKCC expression in all GIT tissues. Regardless of PNH3 gradients, the stomach showed the greatest absorption and net tissue consumption of ammonia. Overall, our findings suggest nitrogen metabolism zonation of GIT, with stomach serving as an important site for the absorption, handling and transport of ammonia that is independent of the PNH3 gradient.
Collapse
Affiliation(s)
- Ellen H Jung
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica Nguyen
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Charlotte Nelson
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
6
|
Jung EH, Brauner CJ, Wood CM. Do extreme postprandial levels of oxygen, carbon dioxide, and ammonia in the digestive tract equilibrate with the bloodstream in the freshwater rainbow trout (Oncorhynchus mykiss)? J Comp Physiol B 2023; 193:193-205. [PMID: 36656334 DOI: 10.1007/s00360-023-01475-8] [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: 02/18/2022] [Revised: 12/20/2022] [Accepted: 01/06/2023] [Indexed: 01/20/2023]
Abstract
The gastrointestinal tract (GIT) lumen of teleosts harbors extreme conditions, especially after feeding: high PCO2 (20-115 Torr), total ammonia (415-3710 μM), PNH3 (79-1760 μTorr in the intestine), and virtual anoxia (PO2 < 1 Torr). These levels could be dangerous if they were to equilibrate with the bloodstream. Thus, we investigated the potential equilibration of O2, CO2, and ammonia across the GIT epithelia in freshwater rainbow trout by monitoring postprandial arterial and venous blood gases in vivo and in situ. In vivo blood was sampled from the indwelling catheters in the dorsal aorta (DA) and subintestinal vein (SIV) draining the posterior intestine in the fasting state and at 4 to 48 h following catheter-feeding. To investigate possible ammonia absorption in the anterior part of the GIT, blood was sampled from the DA, SIV and hepatic portal vein (HPV) from anaesthetized fish in situ following voluntary feeding. We found minimal equilibration of all three gases between the GIT lumen and the SIV blood, with the latter maintaining pre-feeding levels (PO2 = 25-49 Torr, PCO2 = 6-8 Torr, and total ammonia = 117-134 μM and PNH3 = 13-30 μTorr at 48 h post-feeding). In contrast to the SIV, we found that the HPV total ammonia more than doubled 24 h after feeding (128 to 297 μM), indicative of absorption in the anterior GIT. Overall, the GIT epithelia of trout, although specialized for absorption, prevent dangerous levels of PO2, PCO2 and ammonia from equilibrating with the blood circulation.
Collapse
Affiliation(s)
- Ellen H Jung
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| |
Collapse
|
7
|
Rasmussen JA, Villumsen KR, Ernst M, Hansen M, Forberg T, Gopalakrishnan S, Gilbert MTP, Bojesen AM, Kristiansen K, Limborg MT. A multi-omics approach unravels metagenomic and metabolic alterations of a probiotic and synbiotic additive in rainbow trout (Oncorhynchus mykiss). MICROBIOME 2022; 10:21. [PMID: 35094708 PMCID: PMC8802455 DOI: 10.1186/s40168-021-01221-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/27/2021] [Indexed: 05/02/2023]
Abstract
BACKGROUND Animal protein production is increasingly looking towards microbiome-associated services such as the design of new and better probiotic solutions to further improve gut health and production sustainability. Here, we investigate the functional effects of bacteria-based pro- and synbiotic feed additives on microbiome-associated functions in relation to growth performance in the commercially important rainbow trout (Oncorhynchus mykiss). We combine complementary insights from multiple omics datasets from gut content samples, including 16S bacterial profiling, whole metagenomes, and untargeted metabolomics, to investigate bacterial metagenome-assembled genomes (MAGs) and their molecular interactions with host metabolism. RESULTS Our findings reveal that (I) feed additives changed the microbiome and that rainbow trout reared with feed additives had a significantly reduced relative abundance of the salmonid related Candidatus Mycoplasma salmoninae in both the mid and distal gut content, (II) genome resolved metagenomics revealed that alterations of microbial arginine biosynthesis and terpenoid backbone synthesis pathways were directly associated with the presence of Candidatus Mycoplasma salmoninae, and (III) differences in the composition of intestinal microbiota among feed types were directly associated with significant changes of the metabolomic landscape, including lipids and lipid-like metabolites, amino acids, bile acids, and steroid-related metabolites. CONCLUSION Our results demonstrate how the use of multi-omics to investigate complex host-microbiome interactions enable us to better evaluate the functional potential of probiotics compared to studies that only measure overall growth performance or that only characterise the microbial composition in intestinal environments. Video Abstract.
Collapse
Affiliation(s)
- Jacob Agerbo Rasmussen
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Center for Evolutionary Hologenomics, GLOBE Institute, Faculty of Health and Medical Sciences, Copenhagen, Denmark.
| | - Kasper Rømer Villumsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Veterinary Clinical Microbiology, Copenhagen, Denmark
| | - Madeleine Ernst
- Section for Clinical Mass Spectrometry, Danish Center for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institut, 2300, Copenhagen, Denmark
| | - Martin Hansen
- Department of Environmental Science, Aarhus University, Aarhus, Denmark
| | | | - Shyam Gopalakrishnan
- Center for Evolutionary Hologenomics, GLOBE Institute, Faculty of Health and Medical Sciences, Copenhagen, Denmark
| | - M Thomas P Gilbert
- Center for Evolutionary Hologenomics, GLOBE Institute, Faculty of Health and Medical Sciences, Copenhagen, Denmark
- University Museum NTNU, Trondheim, Norway
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Veterinary Clinical Microbiology, Copenhagen, Denmark
| | - Karsten Kristiansen
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Institute of Metagenomics, Qingdao-Europe Advanced Institute for Life Sciences, Qingdao, China
| | - Morten Tønsberg Limborg
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Center for Evolutionary Hologenomics, GLOBE Institute, Faculty of Health and Medical Sciences, Copenhagen, Denmark.
| |
Collapse
|
8
|
Jung EH, Brauner CJ, Wood CM. Post-prandial respiratory gas and acid-base profiles in the gastrointestinal tract and its venous drainage in freshwater rainbow trout (Oncorhynchus mykiss) and seawater English sole (Parophrys vetulus). Comp Biochem Physiol A Mol Integr Physiol 2021; 265:111123. [PMID: 34856374 DOI: 10.1016/j.cbpa.2021.111123] [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: 07/30/2021] [Revised: 10/15/2021] [Accepted: 11/26/2021] [Indexed: 10/19/2022]
Abstract
The basic respiratory gas and acid-base conditions inside the lumen of the gastrointestinal tract (GIT) and blood draining the tract are largely unestablished in teleost fishes after feeding, though there have been some recent novel discoveries on freshwater rainbow trout (Oncorhynchus mykiss) and seawater English sole (Parophrys vetulus). The present study examined in greater detail the gas (PO2, PCO2, PNH3) and acid-base profiles (pH, [HCO3-], total [ammonia]) in the lumen of the stomach, the anterior, mid, and posterior intestine, as well as the venous drainage (subintestinal and/or hepatic portal vein) of the GIT in these two species 20 h post-feeding. Both species had high PCO2, PNH3, and total [ammonia], and low PO2 (virtual anoxia) in the lumens throughout all sections of the GIT, and high [HCO3-] in the intestine. Total [ammonia], PNH3, and [HCO3-] increased from anterior to posterior intestine in both species. P. vetulus had higher intestinal total [ammonia] and lower [HCO3-] than O. mykiss post feeding, but total [ammonia] was much higher in the stomach of O. mykiss. Despite the extreme conditions in the lumen, both arterial and venous blood showed relatively lower PCO2, total [ammonia] and higher PO2, implying limited equilibration between the two compartments. The higher [HCO3-] and lower total [ammonia] in the intestinal lumen of the freshwater O. mykiss than the seawater P. vetulus suggest the need for future comparative studies using conspecifics fed identical diets but acclimated to the two different salinities in order to understand the potential role of environmental salinity and associated osmoregulatory processes underlying these differences.
Collapse
Affiliation(s)
- Ellen H Jung
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada.
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Bamfield Marine Sciences Centre, Bamfield, BC V0R 1B0, Canada.
| |
Collapse
|
9
|
Rasmussen JA, Villumsen KR, Duchêne DA, Puetz LC, Delmont TO, Sveier H, Jørgensen LVG, Præbel K, Martin MD, Bojesen AM, Gilbert MTP, Kristiansen K, Limborg MT. Genome-resolved metagenomics suggests a mutualistic relationship between Mycoplasma and salmonid hosts. Commun Biol 2021; 4:579. [PMID: 33990699 PMCID: PMC8121932 DOI: 10.1038/s42003-021-02105-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/14/2021] [Indexed: 11/08/2022] Open
Abstract
Salmonids are important sources of protein for a large proportion of the human population. Mycoplasma species are a major constituent of the gut microbiota of salmonids, often representing the majority of microbiota. Despite the frequent reported dominance of salmonid-related Mycoplasma species, little is known about the phylogenomic placement, functions and potential evolutionary relationships with their salmonid hosts. In this study, we utilise 2.9 billion metagenomic reads generated from 12 samples from three different salmonid host species to I) characterise and curate the first metagenome-assembled genomes (MAGs) of Mycoplasma dominating the intestines of three different salmonid species, II) establish the phylogeny of these salmonid candidate Mycoplasma species, III) perform a comprehensive pangenomic analysis of Mycoplasma, IV) decipher the putative functionalities of the salmonid MAGs and reveal specific functions expected to benefit the host. Our data provide a basis for future studies examining the composition and function of the salmonid microbiota.
Collapse
Affiliation(s)
- Jacob A Rasmussen
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Kasper R Villumsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Veterinary Clinical Microbiology, Copenhagen, Denmark
| | - David A Duchêne
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lara C Puetz
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tom O Delmont
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, Evry, France
| | | | - Louise von Gersdorff Jørgensen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Parasitology and Aquatic Pathobiology, Copenhagen, Denmark
| | - Kim Præbel
- Norwegian College of Fishery Science, UiT the Arctic University of Norway, Tromsø, Norway
| | - Michael D Martin
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Anders M Bojesen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Veterinary Clinical Microbiology, Copenhagen, Denmark
| | - M Thomas P Gilbert
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Karsten Kristiansen
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Institute of Metagenomics, BGI-Shenzhen, Shenzhen, China
| | - Morten T Limborg
- Laboratory of Genomics and Molecular Medicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Center for Evolutionary Hologenomics, GLOBE institute, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
10
|
Jung EH, Smich J, Rubino JG, Wood CM. An in vitro study of urea and ammonia production and transport by the intestinal tract of fed and fasted rainbow trout: responses to luminal glutamine and ammonia loading. J Comp Physiol B 2021; 191:273-287. [PMID: 33415429 DOI: 10.1007/s00360-020-01335-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/17/2020] [Accepted: 12/06/2020] [Indexed: 12/28/2022]
Abstract
Digestion of dietary protein in teleosts results in high ammonia levels within the intestinal chyme that may reach concentrations that are many-fold greater than blood plasma levels. We used in vitro gut sac preparations of the ammoniotelic rainbow trout (Oncorhynchus mykiss) to investigate the role of the intestine in producing and transporting ammonia and urea, with specific focus on feeding versus fasting, and on responses to loading of the lumen with 2 mmol L-1 glutamine or 2 mmol L-1 ammonia. Feeding increased not only ammonia production and both mucosal and serosal fluxes, but also increased urea production and serosal fluxes. Elevated urea production was accompanied by an increase in arginase activity but minimal CPS III activity, suggesting that urea may be produced by direct arginolysis. The ammonia production and serosal fluxes increased in fasted preparations with glutamine loading, indicating an ability of the intestinal tissue to deaminate glutamine and perhaps use it as an energy source. However, there was little evidence of urea production or transport resulting from the presence of glutamine. Furthermore, the intestinal tissues did not appear to convert surplus ammonia to urea as a detoxification mechanism, as urea production and serosal flux rates decreased in fed preparations, with minimal changes in fasted preparations. Nevertheless, there was indirect evidence of detoxification by another pathway, as ammonia production rate decreased with ammonia loading in fed preparations. Overall, our study suggests that intestinal tissues of rainbow trout have the ability to produce urea and detoxify ammonia, likely via arginolysis.
Collapse
Affiliation(s)
- Ellen H Jung
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
| | - Joanna Smich
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON, L8S 4K1, Canada.,Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 166, 02-787, Warsaw, Poland
| | - Julian G Rubino
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON, L8S 4K1, Canada
| | - Chris M Wood
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.,Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON, L8S 4K1, Canada
| |
Collapse
|
11
|
The gaseous gastrointestinal tract of a seawater teleost, the English sole (Parophrys vetulus). Comp Biochem Physiol A Mol Integr Physiol 2020; 247:110743. [PMID: 32531535 DOI: 10.1016/j.cbpa.2020.110743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
Abstract
There has been considerable recent progress in understanding the respiratory physiology of the gastrointestinal tract (GIT) in teleosts, but the respiratory conditions inside the GIT remain largely unknown, particularly the luminal PCO2 and PO2 levels. The GIT of seawater teleosts is of special interest due to its additional function of water absorption linked to HCO3- secretion, a process that may raise luminal PCO2 levels. Direct measurements of GIT PCO2 and PO2 using micro-optodes in the English sole (Parophrys vetulus; anaesthetized, artificially ventilated, 10-12 °C) revealed extreme luminal gas levels. Luminal PCO2 was 14-17 mmHg in the stomach and intestinal segments of fasted sole, considerably higher than arterial blood levels of 5 mmHg. Moreover, feeding, which raised intestinal HCO3- concentration, also raised luminal PCO2 to 34-50 mmHg. All these values were higher than comparable measurements in freshwater teleosts, and also greater than environmental CO2 levels of concern in aquaculture or global change scenarios. The PCO2 values in subintestinal vein blood draining the GIT of fed fish (28 mmHg) suggested some degree of equilibration with high luminal PCO2, whereas subintestinal vein PO2 levels were relatively low (9 mmHg). All luminal sections of the GIT were virtually anoxic (PO2 ≤ 0.3 mmHg), in both fasted and fed animals, a novel finding in teleosts.
Collapse
|
12
|
Li X, Zheng S, Wu G. Nutrition and metabolism of glutamate and glutamine in fish. Amino Acids 2020; 52:671-691. [PMID: 32405703 DOI: 10.1007/s00726-020-02851-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/29/2020] [Indexed: 12/14/2022]
Abstract
Glutamate (Glu) and glutamine (Gln) comprise a large proportion of total amino acids (AAs) in fish in the free and protein-bound forms. Both Glu and Gln are synthesized de novo from other α-amino acids and ammonia. Although these two AAs had long been considered as nutritionally non-essential AAs for an aquatic animal, they must be included adequately in its diet to support optimal health (particularly intestinal health) and maximal growth. In research on fish nutrition, Glu has been used frequently as an isonitrogenous control on the basis of the assumption that this AA has no nutritional or physiological function. In addition, purified diets used for feeding fish generally lack glutamine. As functional AAs, Glu and Gln are major metabolic fuels for tissues of fish (including the intestine, liver, kidneys, and skeletal muscle), and play important roles not only in protein synthesis but also in glutathione synthesis and anti-oxidative reactions. The universality of Glu and Gln as abundant intracellular AAs depends on their enormous versatility in metabolism. Dietary supplementation with Glu and Gln to farmed fish can improve their growth performance, intestinal development, innate and adaptive immune responses, skeletal muscle development and fillet quality, ammonia removal, and the endocrine status. Glu (mainly as monosodium glutamate), glutamine, or AminoGut (a mixture of Glu and Gln) is a promising feed additive to reduce the use of fishmeal, while gaining the profitability of global aquaculture production. Thus, the concept of dietary requirements of fish for Glu and Gln is a paradigm shift in the nutrition of aquatic animals (including fish).
Collapse
Affiliation(s)
- Xinyu Li
- Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA
| | - Shixuan Zheng
- Guangdong Yuehai Feeds Group Co., Ltd, Zhanjiang, 524017, Guangdong, China
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA.
| |
Collapse
|
13
|
Turner LA, Bucking C. The role of intestinal bacteria in the ammonia detoxification ability of teleost fish. ACTA ACUST UNITED AC 2019; 222:jeb.209882. [PMID: 31753905 DOI: 10.1242/jeb.209882] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 11/13/2019] [Indexed: 12/23/2022]
Abstract
Protein catabolism during digestion generates appreciable levels of ammonia in the gastrointestinal tract (GIT) lumen. Amelioration by the enterocyte, via enzymes such as glutamine synthetase (GS), glutamate dehydrogenase (GDH), and alanine and aspartate aminotransferases (ALT; AST), is found in teleost fish. Conservation of these enzymes across bacterial phyla suggests that the GIT microbiome could also contribute to ammonia detoxification by providing supplemental activity. Hence, the GIT microbiome, enzyme activities and ammonia detoxification were investigated in two fish occupying dissimilar niches: the carnivorous rainbow darter and the algivorous central stoneroller. There was a strong effect of fish species on the activity levels of GS, GDH, AST and ALT, as well as GIT lumen ammonia concentration, and bacterial composition of the GIT microbiome. Furthermore, removal of the intestinal bacteria impacted intestinal activities of GS and ALT in the herbivorous fish but not in the carnivore. The repeatability and robustness of this relationship was tested across field locations and years. Within an individual waterbody, there was no impact of sampling location on any of these factors. However, different waterbodies affected enzyme activities and luminal ammonia concentrations in both fish, while only the central stoneroller intestinal bacteria populations varied. Overall, a relationship between GIT bacteria, enzyme activity and ammonia detoxification was observed in herbivorous fish while the carnivorous fish displayed a correlation between enzyme activity and ammonia detoxification alone that was independent of the GIT microbiome. This could suggest that carnivorous fish are less dependent on non-host mechanisms for ammonia regulation in the GIT.
Collapse
Affiliation(s)
- Leah A Turner
- Department of Biology, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
| | - Carol Bucking
- Department of Biology, York University, 4700 Keele St, Toronto, ON M3J 1P3, Canada
| |
Collapse
|
14
|
An in vitro analysis of intestinal ammonia transport in fasted and fed freshwater rainbow trout: roles of NKCC, K + channels, and Na +, K + ATPase. J Comp Physiol B 2019; 189:549-566. [PMID: 31486919 DOI: 10.1007/s00360-019-01231-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/15/2019] [Accepted: 08/21/2019] [Indexed: 12/20/2022]
Abstract
We examined mechanisms of ammonia handling in the anterior, mid, and posterior intestine of unfed and fed freshwater rainbow trout (Oncorhynchus mykiss), with a focus on the Na+:K+:2Cl- co-transporter (NKCC), Na+:K +-ATPase (NKA), and K+ channels. NKCC was localized by immunohistochemistry to the mucosal (apical) surface of enterocytes, and NKCC mRNA was upregulated after feeding in the anterior and posterior segments. NH4+ was equally potent to K+ in supporting NKA activity in all intestinal sections. In vitro gut sac preparations were employed to examine mucosal ammonia flux rates (Jmamm, disappearance from the mucosal saline), serosal ammonia flux rates (Jsamm, appearance in the serosal saline), and total tissue ammonia production rates (Jtamm = Jsamm - Jmamm). Bumetanide (10-4 mol L-1), a blocker of NKCC, inhibited Jsamm in most preparations, but this was largely due to reduction of Jtamm; Jmamm was significantly inhibited only in the anterior intestine of fed animals. Ouabain (10-4 mol L-1), a blocker of NKA, generally reduced both Jmamm and Jsamm without effects on Jtamm in most preparations, though the anterior intestine was resistant after feeding. Barium (10-2 mol L-1), a blocker of K+ channels, inhibited Jmamm in most preparations, and Jsamm in some, without effects on Jtamm. These pharmacological results, together with responses to manipulations of serosal and mucosal Na+ and K+ concentrations, suggest that NKCC is not as important in ammonia absorption as previously believed. NH4+ appears to be taken up through barium-sensitive K+ channels on the mucosal surface. Mucosal NH4+ uptake via both NKCC and K+ channels is energized by basolateral NKA, which plays an additional role in scavenging NH4+ on the serosal surface to possibly minimize blood toxicity or enhance ion uptake and amino acid synthesis following feeding. Together with recent findings from other studies, we have provided an updated model to describe the current understanding of intestinal ammonia transport in teleost fish.
Collapse
|
15
|
Williams M, Barranca D, Bucking C. Zonation of Ca 2+ transport and enzyme activity in the caeca of rainbow trout - a simple structure with complex functions. ACTA ACUST UNITED AC 2019; 222:jeb.187484. [PMID: 30765468 DOI: 10.1242/jeb.187484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 02/07/2019] [Indexed: 11/20/2022]
Abstract
Trout caeca are vermiform structures projecting from the anterior intestine of the gastrointestinal tract. Despite their simple gross morphology, these appendages are physically distinct along the anterior-posterior axis, and ultrastructural evidence suggests zonation of function within the structures. Individual caeca from three sections (anterior, middle and posterior) were removed from the intestine of freshwater rainbow trout and investigated for ion transport and enzyme activity. Ca2+ absorption appeared as a combination of active and passive movement, with Michaelis-Menten kinetics observable under symmetrical conditions, and was inhibited by several pharmacological agents (ouabain, La3+ and a calmodulin antagonist). There was a decrease in ion transport function from adjacent to the intestine (proximal) to the distal tip of each caecum, along with decreasing transport from anterior to posterior for the proximal portion alone. Feeding increased the J Max and K M for Ca2+ absorption within all sections, whereas ion-poor water (IPW) exposure further increased the J Max and K M for Ca2+ transport in the anterior and middle sections. Increased Na+/K+-ATPase (NKA) and citrate synthase (CS) activity rates paralleled trends seen in Ca2+ transport. Feeding in freshwater and IPW exposure increased the glycolytic capacity of the caeca via increased pyruvate kinase (PK) and decreased lactate dehydrogenase (LDH) activity, while amino acid metabolism increased with IPW exposure through increased glutamate dehydrogenase (GDH) activity. Overall, feeding and IPW exposure each altered ionoregulation within the caeca of freshwater rainbow trout in a zone-specific pattern, with the anterior and proximal portions of the caeca being most affected. Increased carbohydrate and protein metabolism fueled the increased ATP demand of NKA through CS.
Collapse
Affiliation(s)
- Melanie Williams
- Department of Biology, York University, Toronto, Ontario, Canada, M3J 1P3
| | - Domenico Barranca
- Department of Biology, York University, Toronto, Ontario, Canada, M3J 1P3
| | - Carol Bucking
- Department of Biology, York University, Toronto, Ontario, Canada, M3J 1P3
| |
Collapse
|
16
|
Wood CM, Liew HJ, De Boeck G, Hoogenboom JL, Anderson WG. Nitrogen handling in the elasmobranch gut: a role for microbial urease. ACTA ACUST UNITED AC 2019; 222:jeb.194787. [PMID: 30530835 DOI: 10.1242/jeb.194787] [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: 10/16/2018] [Accepted: 12/03/2018] [Indexed: 11/20/2022]
Abstract
Ureotelic elasmobranchs require nitrogen for both protein growth and urea-based osmoregulation, and therefore are probably nitrogen-limited in nature. Mechanisms exist for retaining and/or scavenging nitrogen in the gills, kidney, rectal gland and gut, but as yet, the latter are not well characterized. Intestinal sac preparations of the Pacific spiny dogfish shark (Squalus acanthias suckleyi) incubated in vitro strongly reabsorbed urea from the lumen after feeding, but mucosal fluid ammonia concentrations increased with incubation time. Phloretin (0.25 mmol l-1, which blocked urea reabsorption) greatly increased the rate of ammonia accumulation in the lumen. A sensitive [14C]urea-based assay was developed to examine the potential role of microbial urease in this ammonia production. Urease activity was detected in chyme/intestinal fluid and intestinal epithelial tissue of both fed and fasted sharks. Urease was not present in gall-bladder bile. Urease activities were highly variable among animals, but generally greater in chyme than in epithelia, and greater in fed than in fasted sharks. Comparable urease activities were found in chyme and epithelia of the Pacific spotted ratfish (Hydrolagus colliei), a ureotelic holocephalan, but were much lower in ammonotelic teleosts. Urease activity in dogfish chyme was inhibited by acetohydroxamic acid (1 mmol l-1) and by boiling. Treatment of dogfish gut sac preparations with acetohydroxamic acid blocked ammonia production, changing net ammonia accumulation into net ammonia absorption. We propose that microbial urease plays an important role in nitrogen handling in the elasmobranch intestine, allowing some urea-N to be converted to ammonia, which is then reabsorbed for amino acid synthesis or reconversion to urea.
Collapse
Affiliation(s)
- Chris M Wood
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada .,Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.,Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada
| | - Hon Jung Liew
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia
| | - Gudrun De Boeck
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Systemic Physiological and Ecotoxicological Research, Department of Biology, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp, Belgium
| | - J Lisa Hoogenboom
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
| | - W Gary Anderson
- Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
| |
Collapse
|
17
|
Turner LA, Bucking C. The interactive effect of digesting a meal and thermal acclimation on maximal enzyme activities in the gill, kidney, and intestine of goldfish (Carassius auratus). J Comp Physiol B 2017; 187:959-972. [PMID: 28382530 DOI: 10.1007/s00360-017-1068-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 02/08/2017] [Accepted: 02/21/2017] [Indexed: 11/30/2022]
Abstract
Surrounding environmental temperatures affect many aspects of ectotherm physiology. Generally, organisms can compensate at one or more biological levels, or allow temperature to dictate processes such as enzyme activities through kinetic effects on reaction rates. As digestion also alters physiological processes such as enzyme activities, this study determined the interacting effect of thermal acclimation (8 and 20 °C) and digesting a single meal on maximal enzyme activities in three tissues of the goldfish (Carrassius auratus). Acclimation to elevated temperatures decreased branchial Na+, K+, ATPase (NKA) activity. In contrast, acclimation to elevated temperatures had no effect on citrate synthase (CS) or pyruvate kinase (PK) activity in any tissue, nor were renal NKA or glutamine synthetase (GS) activities impacted. Warm water-acclimation exaggerated the positive impact of digestion on intestinal and branchial NKA activities and intestinal GS activity only, but digestion had no effect in the kidney. CS and PK did not display intestinal zonation; however, there was a distinct increase towards the distal intestine in NKA and GS activities. Zonation of NKA was more prominent in warm-acclimated animals, while acclimation temperature did not affect intestinal heterogeneity of GS. Finally, the impact of tissue protein content on enzyme activity was discussed. We conclude that the intestine and gill of warm-acclimated goldfish exhibited an augmented capacity for increasing several enzyme activities in response to digestion while the kidney was unaffected by thermal acclimation or digesting a single meal. However, this amplified capacity was ameliorated by alterations in tissue protein content. Amplified increases in NKA activity may ultimately have implications for ATP demand in these tissues, while increased GS activity may beneficially increase ammonia-detoxifying capacity in the intestine.
Collapse
Affiliation(s)
- Leah A Turner
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Carol Bucking
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
| |
Collapse
|
18
|
Bucking C. A broader look at ammonia production, excretion, and transport in fish: a review of impacts of feeding and the environment. J Comp Physiol B 2016; 187:1-18. [PMID: 27522221 DOI: 10.1007/s00360-016-1026-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 12/23/2022]
Abstract
For nearly a century, researchers have studied ammonia production and excretion in teleost fish. Stemming from past investigations a body of knowledge now exists on various aspects including biochemical mechanisms of ammonia formation and specific routes and tissues used for ammonia transport, culminating in a current detailed theoretical model of branchial transport, including the molecular identities of the moieties involved. However, typical studies examining ammonia balance use routine laboratory conditions and fasted fish. While avoiding additional variables that influence nitrogen balance, these studies are arguably idealistic and do not reflect the natural variety of conditions that fish encounter. Further studies have revealed the impacts of extrinsic factors (e.g. salinity, pH, temperature) on ammonia handling in fasted fish whereas others have explored intrinsic factors, such as life history and developmental impacts. One routine challenge for ammonia balance that fish encounter is feeding and digestion. Fortunately, many new studies have revealed the impact of feeding and digestion on several aspects of ammonia balance; from production to excretion and to transport, and several have done so incorporating supplemental extrinsic and/or intrinsic factors. Together, these complex studies reveal realistic responses to multifactorial challenges encountered by animals in the wild and begin to provide a holistic view of ammonia balance in freshwater teleost fish.
Collapse
Affiliation(s)
- Carol Bucking
- Department of Biology, Farquharson Life Science Building, York University, Toronto, ON, M3J 1P3, Canada.
| |
Collapse
|
19
|
Rubino JG, Zimmer AM, Wood CM. Intestinal ammonia transport in freshwater and seawater acclimated rainbow trout (Oncorhynchus mykiss): evidence for a Na+ coupled uptake mechanism. Comp Biochem Physiol A Mol Integr Physiol 2014; 183:45-56. [PMID: 25545914 DOI: 10.1016/j.cbpa.2014.12.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 12/17/2014] [Accepted: 12/19/2014] [Indexed: 12/23/2022]
Abstract
In vitro gut sac experiments were performed on freshwater and 60% seawater acclimated trout (Oncorhynchus mykiss) under treatments designed to discern possible mechanisms of intestinal ammonia transport. Seawater acclimation increased ammonia flux rate into the serosal saline (Jsamm) in the anterior intestine, however it did not alter Jsamm in the mid- or posterior intestine suggesting similar mechanisms of ammonia handling in freshwater and seawater fish. Both fluid transport rate (FTR) and Jsamm were inhibited in response to basolateral ouabain treatment, suggesting a linkage of ammonia uptake to active transport, possibly coupled to fluid transport processes via solvent drag. Furthermore, decreases in FTR and Jsamm caused by low Na(+) treatment indicated a Na(+) linked transport mechanism. Mucosal bumetanide (10(-4) M) had no impact on FTR, yet decreased Jsamm in the anterior and mid-intestine, suggesting NH4(+) substitution for K(+) on an apical NKCC, and at least a partial uncoupling of ammonia transport from fluid transport. Additional treatments (amiloride, 5-(N-ethyl-N-isopropyl)amiloride (EIPA), phenamil, bafilomycin, 4',6-diamidino-2-phenylindole (DAPI), high sodium) intended to disrupt alternative routes of Na(+) uptake yielded no change in FTR or Jsamm, suggesting the absence of direct competition between Na(+) and ammonia for transport. Finally, [(14)C]methylamine permeability (PMA) measurements indicated the likely presence of an intestinal Rh-mediated ammonia transport system, as increasing NH4Cl (0, 1, 5 mmol l(-1)) concentrations reduced PMA, suggesting competition for transport through Rh proteins. Overall, the data presented in this paper provide some of the first insights into mechanisms of teleost intestinal ammonia transport.
Collapse
Affiliation(s)
- Julian G Rubino
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada.
| | - Alex M Zimmer
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada
| | - Chris M Wood
- McMaster University, Life Sciences Building, Department of Biology, Hamilton, Ontario L8S 4K1, Canada; Bamfield Marine Sciences Centre, Bamfield, British Columbia V0R 1B0, Canada; Dept. of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| |
Collapse
|
20
|
Pelster B, Wood CM, Speers-Roesch B, Driedzic WR, Almeida-Val V, Val A. Gut transport characteristics in herbivorous and carnivorous serrasalmid fish from ion-poor Rio Negro water. J Comp Physiol B 2014; 185:225-41. [DOI: 10.1007/s00360-014-0879-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/11/2014] [Accepted: 11/22/2014] [Indexed: 10/24/2022]
|