| 1. |
- Lind, Ulrika, et al.
(författare)
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Analysis of aquaporins from the euryhaline barnacle Balanus improvisus reveals differential expression in response to changes in salinity
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Barnacles are sessile macro-invertebrates, found along rocky shores in coastal areas worldwide. The euryhaline bay barnacle Balanus improvisus (Darwin, 1854) (= Amphibalanus improvisus) can tolerate a wide range of salinities, but the molecular mechanisms underlying the osmoregulatory capacity of this truly brackish species are not well understood. Aquaporins are pore-forming integral membrane proteins that facilitate transport of water, small solutes and ions through cellular membranes, and that have been shown to be important for osmoregulation in many organisms. The knowledge of the function of aquaporins in crustaceans is, however, limited and nothing is known about them in barnacles. We here present the repertoire of aquaporins from a thecostracan crustacean, the barnacle B. improvisus, based on genome and transcriptome sequencing. Our analyses reveal that B. improvisus contains eight genes for aquaporins. Phylogenetic analysis showed that they represented members of the classical water aquaporins (Aqp1, Aqp2), the aquaglyceroporins (Glp1, Glp2), the unorthodox aquaporin (Aqp12) and the arthropod-specific big brain aquaporin (Bib). Interestingly, we also found two big brain-like proteins (BibL1 and BibL2) constituting a new group of aquaporins not yet described in arthropods. In addition, we found that the two water-specific aquaporins were expressed as C-terminal splice variants. Heterologous expression of some of the aquaporins followed by functional characterization showed that Aqp1 transported water and Glp2 water and glycerol, agreeing with the predictions of substrate specificity based on 3D modeling and phylogeny. To investigate a possible role for the B. improvisus aquaporins in osmoregulation, mRNA expression changes in adult barnacles were analysed after long-term acclimation to different salinities. The most pronounced expression difference was seen for AQP1 with a substantial (>100-fold) decrease in the mantle tissue in low salinity (3 PSU) compared to high salinity (33 PSU). Our study provides a base for future mechanistic studies on the role of aquaporins in osmoregulation. © 2017 Lind et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 2. |
- Rosengren, Malin, 1982, et al.
(författare)
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Born to be wild: effects of rearing density and environmental enrichment on stress, welfare, and smolt migration in hatchery-reared Atlantic salmon
- 2017
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 74:3, s. 396-405
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Tidskriftsartikel (refereegranskat)abstract
- Hatchery-reared salmonids released into the wild generally have poor survivability compared with wild conspecifics. To assess potential hatchery rearing improvements, behavioral and physiological effects of reducing animal density and adding in-tank shelter were investigated. Atlantic salmon (Salmo salar) parr were placed in barren or shelter-enriched tanks at high or low density up until release as smolts. Lowered density rendered positive effects on growth and intestinal barrier function, and both lowered density and shelter decreased conspecific aggression, as inferred by fin damage. Furthermore, while the presence of shelter decreased stress hormone levels following human disturbance, it also decreased growth and smolt migration success, an effect particularly pronounced at high densities. Therefore, we suggest that this type of structural enrichment should be avoided for Atlantic salmon smolts held at high densities and conclude that a lowered animal density with or without shelter has the highest potential in producing a more resilient smolt for stocking.
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| 3. |
- Rosengren, Malin, 1982, et al.
(författare)
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High risk no gain-metabolic performance of hatchery reared Atlantic salmon smolts, effects of nest emergence time, hypoxia avoidance behaviour and size
- 2017
-
Ingår i: Physiology & Behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 175, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- When animals are reared for conservational releases it is paramount to avoid reducing genetic and phenotypic variation over time. This requires an understanding of how diverging behavioural and physiological traits affect performance both in captivity and after release. In Atlantic salmon, emergence time from the spawning gravel has been linked to certain behavioural and physiological characteristics and to the concept of stress coping styles. Early emerging fry has for example been shown to be bolder and more aggressive and to have higher standard metabolic rates compared to late emerging fry. The first aim was therefore to examine if emergence latency affect the behavioural stress coping response also beyond the fry and parr stage. This was done using a hypoxia avoidance test, where an active behavioural avoidance response can be related to higher risk taking. No behavioural differences were found between the two emergence fractions either at the parr or pre-smolt stage, instead smaller individuals were more prone to express an "active" hypoxia avoidance response. Further, an individual expressing a "passive" response as parr were also more prone to express this behaviour at the pre-smolt stage. While there are some previous studies showing that early emerging individuals with a bolder personality may be favored within a hatchery setting it is not known to what extent these early differences persist to affect performance after release. The second aim was therefore to compare the physiological performance at the time of release as smolts using the two subgroups; 1) early emerging fish showing active hypoxia avoidance (Early + Bold) and 2) late emerging fish showing a passive hypoxia response (Late + Shy). The Early + Bold group showed a higher red blood cell swelling, suggesting a higher adrenergic output during stress, whereas there was no difference in post-stress plasma cortisol or physiological smolt status. While there was no difference in standard metabolic rate between the groups, the Early + Bold group exhibited a lower maximum metabolic rate and aerobic scope following strenuous swimming. In captivity this may have no clear negative effects, but in the wild, a more risk prone behavioural profile linked to a lower aerobic capacity to escape from e.g. a predator attack, could clearly be disadvantageous.
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| 4. |
- Alves, R. N., et al.
(författare)
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Structural and functional maturation of skin during metamorphosis in the Atlantic halibut (Hippoglossus hippoglossus)
- 2018
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 372:3, s. 469-492
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Tidskriftsartikel (refereegranskat)abstract
- To establish if the developmental changes in the primary barrier and osmoregulatory capacity of Atlantic halibut skin are modified during metamorphosis, histological, histochemical, gene expression and electrophysiological measurements were made. The morphology of the ocular and abocular skin started to diverge during the metamorphic climax and ocular skin appeared thicker and more stratified. Neutral mucins were the main glycoproteins produced by the goblet cells in skin during metamorphosis. Moreover, the number of goblet cells producing neutral mucins increased during metamorphosis and asymmetry in their abundance was observed between ocular and abocular skin. The increase in goblet cell number and their asymmetric abundance in skin was concomitant with the period that thyroid hormones (THs) increase and suggests that they may be under the control of these hormones. Several mucin transcripts were identified in metamorphosing halibut transcriptomes and Muc18 and Muc5AC were characteristic of the body skin. Na+, K+-ATPase positive (NKA) cells were observed in skin of all metamorphic stages but their number significantly decreased with the onset of metamorphosis. No asymmetry was observed between ocular and abocular skin in NKA cells. The morphological changes observed were linked to modified skin barrier function as revealed by modifications in its electrophysiological properties. However, the maturation of the skin functional characteristics preceded structural maturation and occurred at stage 8 prior to the metamorphic climax. Treatment of Atlantic halibut with the THs disrupter methimazole (MMI) affected the number of goblet cells producing neutral mucins and the NKA cells. The present study reveals that the asymmetric development of the skin in Atlantic halibut is TH sensitive and is associated with metamorphosis and that this barrier's functional properties mature earlier and are independent of metamorphosis.
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| 5. |
- Benktander, John, et al.
(författare)
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Effects of Size and Geographical Origin on Atlantic salmon, Salmo salar, Mucin O-Glycan Repertoire
- 2019
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476. ; 18:6, s. 1183-1196
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Tidskriftsartikel (refereegranskat)abstract
- Diseases cause ethical concerns and economic losses in the Salmonid industry. The mucus layer comprised of highly O-glycosylated mucins is the first contact between pathogens and fish. Mucin glycans govern pathogen adhesion, growth and virulence. The Atlantic salmon O-glycome from a single location has been characterized and the interindividual variation was low. Because interindividual variation is considered a population-based defense, hindering the entire population from being wiped out by a single infection, low interindividual variation among Atlantic salmon may be a concern. Here, we analyzed the O-glycome of 25 Atlantic salmon from six cohorts grown under various conditions from Sweden, Norway and Australia (Tasmania) using mass spectrometry. This expanded the known Atlantic salmon O-glycome by 60% to 169 identified structures. The mucin O-glycosylation was relatively stable over time within a geographical region, but the size of the fish affected skin mucin glycosylation. The skin mucin glycan repertoires from Swedish and Norwegian Atlantic salmon populations were closely related compared with Tasmanian ones, regardless of size and salinity, with differences in glycan size and composition. The internal mucin glycan repertoire also clustered based on geographical origin and into pyloric cecal and distal intestinal groups, regardless of cohort and fish size. Fucosylated structures were more abundant in Tasmanian pyloric caeca and distal intestine mucins compared with Swedish ones. Overall, Tasmanian Atlantic salmon mucins have more O-glycan structures in skin but less in the gastrointestinal tract compared with Swedish fish. Low interindividual variation was confirmed within each cohort. The results can serve as a library for identifying structures of importance for host-pathogen interactions, understanding population differences of salmon mucin glycosylation in resistance to diseases and during breeding and selection of strains. The results could make it possible to predict potential vulnerabilities to diseases and suggest that inter-region breeding may increase the glycan diversity.
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| 6. |
- Brijs, Jeroen, et al.
(författare)
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Increased mitochondrial coupling and anaerobic capacity minimizes aerobic costs of trout in the sea
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Anadromy is a distinctive life-history strategy in fishes that has evolved independently many times. In an evolutionary context, the benefits of anadromy for a species or population must outweigh the costs and risks associated with the habitat switch. The migration of fish across the freshwater-ocean boundary coincides with potentially energetically costly osmoregulatory modifications occurring at numerous levels of biological organization. By integrating whole animal and sub-cellular metabolic measurements, this study presents significant findings demonstrating how an anadromous salmonid (i.e. rainbow trout, Oncorhynchus mykiss) is able to transform from a hyper- to hypo-osmoregulatory state without incurring significant increases in whole animal oxygen consumption rate. Instead, underlying metabolic mechanisms that fuel the osmoregulatory machinery at the organ level (i.e. intestine) are modulated, as mitochondrial coupling and anaerobic metabolism are increased to satisfy the elevated energetic demands. This may have positive implications for the relative fitness of the migrating individual, as aerobic capacity may be maintained for locomotion (i.e. foraging and predator avoidance) and growth. Furthermore, the ability to modulate mitochondrial metabolism in order to maintain osmotic balance suggests that mitochondria of anadromous fish may have been a key target for natural selection, driving species adaptations to different aquatic environments.
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| 7. |
- Brijs, J., et al.
(författare)
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Prospects and pitfalls of using heart rate bio-loggers to assess the welfare of rainbow trout (Oncorhynchus mykiss) in aquaculture
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 509, s. 188-197
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Tidskriftsartikel (refereegranskat)abstract
- - Investigating real-time stress responses during common aquaculture practices is necessary for improving the welfare of farmed fish. Recently, Star-Oddi DST milli-HRT bio-loggers capable of measuring heart rate (as an indicator for stress) in freely swimming fish have proved to be useful in this regard. However, despite the growing popularity of these devices, they have not yet been stringently evaluated and validated for use in fish. The present study is the first to do so by simultaneously recording heart rate of a commercially important salmonid species (rainbow trout, Oncorhynchus mykiss) using the abovementioned bio-loggers, as well as an established non-invasive wireless heart rate recording technique that has been demonstrated to provide more accurate recordings than those collected using traditional methods requiring a physical connection to recording equipment. The measurement error of the bio-loggers was <1 beat min −1 irrespective of the sampling period when only using measurements graded with the highest quality index (QI 0 ) and it is advised that only QI 0 measurements be used as inclusion of poorer quality measurements (QI 1–3 ) markedly reduce measurement accuracy. Furthermore, sufficiently long recovery periods should be employed prior to collecting data with these devices in salmonids, as anaesthesia and surgical implantation of bio-loggers resulted in transiently elevated resting heart rates for >72 h. Following the successful validation of these bio-loggers, the effects of common aquaculture practices such as netting, grouping and enforced activity on the cardiac performance of freely swimming rainbow trout were investigated. Prior to the subsequent exposure to the abovementioned stressors, mean heart rates of trout were ~42 beats min −1 . Following netting, trout increased heart rates by 57%, which recovered within 3 h. Grouping subsequently induced a more pronounced and prolonged stress response, as heart rates initially increased by 86% and then remained elevated throughout the 8 h recovery period. Consequently, trout were only able to further increase heart rates by 7% following enforced activity. This diminished cardiac response demonstrates a situation where the cumulative allostatic load induced by prior stressors is approaching a level where the animal struggles to perform normal physiological processes in the face of further challenges. These findings are important for the aquaculture industry as exposure to multiple stressors without sufficient recovery times has the potential to result in the collapse of cardiac scope, which combined with unfavourable environmental conditions could lead to increased mortality. © 2019 Elsevier B.V.
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| 8. |
- Brijs, J., et al.
(författare)
-
Remote physiological monitoring provides unique insights on the cardiovascular performance and stress responses of freely swimming rainbow trout in aquaculture
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Investigating the mechanisms that fish employ to maintain homeostasis in their everyday life requires measurements of physiological and behavioural responses in the field. With multivariate bio-loggers, we continuously measured gastrointestinal blood flow (GBF), heart rate, activity and body temperature in rainbow trout (Oncorhynchus mykiss) swimming freely amongst ~5000 conspecifics in a sea cage. Our findings clearly demonstrate that while both acute aquaculture-related stress and spontaneous activity resulted in transient reductions in GBF (i.e. reductions of up to 65%), recovery from stressful handling practices subsequently involved a substantial and prolonged gastrointestinal hyperemia far beyond the level observed prior to the stressor. The gastrointestinal hyperemia may be necessary to repair the damage to the gastrointestinal tract caused by acute stress. Furthermore, heart rate responses to acute stress or voluntary activity differed depending on the individual’s physiological state. Stressed fish (i.e. mean heart rates >70 beats min−1) exhibited a bradycardic response to acute stress or activity, whereas fish with mean heart rates <60 beats min−1 instead demonstrated strong tachycardic responses. Remote monitoring of physiological and behavioural variables using bio-loggers can provide unique insights into ‘real-life’ responses of animals, which can largely differ from the responses observed in confined laboratory settings. © 2019, The Author(s).
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| 9. |
- Brijs, Jeroen, et al.
(författare)
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The final countdown: Continuous physiological welfare evaluation of farmed fish during common aquaculture practices before and during harvest
- 2018
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 495, s. 903-911
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Tidskriftsartikel (refereegranskat)abstract
- Welfare of farmed fish has become of increasing concern for consumers, producers, interest groups and authorities. To improve fish welfare, it is necessary to find indicators that can identify stressful situations early enough so that an intervention can take place before detrimental effects occur. By using heart rate bio-loggers in freely swimming rainbow trout (Oncorhynchus mykiss), combined with plasma cortisol levels and a range of haematological and blood chemistry parameters, we assessed the severity of stress responses induced by a range of common aquaculture practices before and during harvest. Following surgery, transportation and reintroduction with conspecifics in the sea cage, it took similar to 4 days for heart rate to stabilize and for a clear circadian rhythm in heart rate to emerge (i.e. average circadian fluctuation in heart rate of similar to 25 to 27 beats min(-1)). The presence or absence of this circadian rhythm in heart rate could inform researchers in the aquaculture industry whether or not specific farming routines induce unnecessary and prolonged stress. The elevations in heart rate caused by common farming practises such as crowding and transportation (e.g. heart rate increased by similar to 8 and 9 beats min-1 above what would normally be expected for that time of day, respectively) corresponded well with increases in plasma cortisol levels. Stressful farming practises or events (indicated by elevated plasma cortisol levels) such as air exposure during brailing and aquatic hypoxia triggered a hypoxic bradycardia until fish were released back into oxygenated water whereupon heart rate significantly increased to repay the accumulated oxygen debt. Repeated stress induced by multiple farming practises (i.e. combined stressors of crowding, brailing and transportation) clearly had a cumulative and long-lasting effect as heart rate peaked at similar to 25 beats min(-1) above what would normally be expected for that time of day. Heart rate also remained significantly elevated by similar to 9 beats min(-1) the following morning, suggesting that if rainbow trout need to be subjected to multiple stressors during consequtive days, it is recommended that sufficient time for recovery is provided between stressors. This study demonstrates that heart rate monitoring can be useful to assess stress levels of freely swimming fish in sea cages. Moreover, the use of implantable bio-loggers opens up a broad range of possible applications that will allow researchers to investigate the effects of environmental and/or anthropogenic stressors on the welfare of fish under conditions more realistic to the aquaculture industry.
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| 10. |
- Callier, Myriam D., et al.
(författare)
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Attraction and repulsion of mobile wild organisms to finfish and shellfish aquaculture: A review
- 2018
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Ingår i: Reviews in Aquaculture. - : Wiley. - 1753-5123 .- 1753-5131. ; 10:4, s. 924-949
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Wiley Publishing Asia Pty Ltd. Knowledge of aquaculture-environment interactions is essential for the development of a sustainable aquaculture industry and efficient marine spatial planning. The effects of fish and shellfish farming on sessile wild populations, particularly infauna, have been studied intensively. Mobile fauna, including crustaceans, fish, birds and marine mammals, also interact with aquaculture operations, but the interactions are more complex and these animals may be attracted to (attraction) or show an aversion to (repulsion) farm operations with various degrees of effects. This review outlines the main mechanisms and effects of attraction and repulsion of wild animals to/from marine finfish cage and bivalve aquaculture, with a focus on effects on fisheries-related species. Effects considered in this review include those related to the provision of physical structure (farm infrastructure acting as fish aggregating devices (FADs) or artificial reefs (ARs), the provision of food (e.g. farmed animals, waste feed and faeces, fouling organisms associated with farm structures) and some farm activities (e.g. boating, cleaning). The reviews show that the distribution of mobile organisms associated with farming structures varies over various spatial (vertical and horizontal) and temporal scales (season, feeding time, day/night period). Attraction/repulsion mechanisms have a variety of direct and indirect effects on wild organisms at the level of individuals and populations and may have implication for the management of fisheries species and the ecosystem in the context of marine spatial planning. This review revealed considerable uncertainties regarding the long-term and ecosystem-wide consequences of these interactions. The use of modelling may help better understand consequences, but long-term studies are necessary to better elucidate effects.
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| 11. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Warmer water temperature results in oxidative damage in an Antarctic fish, the bald notothen
- 2015
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981 .- 1879-1697. ; 468, s. 130-137
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Tidskriftsartikel (refereegranskat)abstract
- Global climate change is predicted to result in increases in water temperature in the polar regions, but the full consequences of this for marine fish species are not understood, especially with regard to cellular mechanisms underlying oxidative stress. Warmer temperatures could potentially result in increased oxidative stress, and it is not known whether stenothermal fish can cope with this on a cellular and physiological level. In order to address this, we exposed bald notothen (Pagothenta borchgrevinki), a fish species endemic to Antarctica, to an increase in temperature from -1.6 degrees C to 4 degrees C and measured the effects on oxidative stress including antioxidant defenses, oxidative damage in proteins and lipids, and transcriptional regulation of involved genes. We show that the fish responds to an acute (12 h) temperature increase with increased antioxidant defenses. However, these antioxidant defenses were similar to basal levels following long-term (3 weeks) exposure to the higher temperature and moreover, these individuals also had higher levels of oxidative damage. These results indicate that this species has the ability to alter levels of endogenous antioxidants, but that this response is transient and insufficient to protect against oxidative damage. These effects may have serious consequences for these fish in a warmer future since long-term consequences of this accumulation of damaged lipids and proteins are associated with aging and known to include decreased cellular function, disease and eventually cell death. (C) 2015 Elsevier B.V. All rights reserved.
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| 12. |
- Gräns, Albin, 1979, et al.
(författare)
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Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses
- 2016
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 10:2, s. 294-301
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Tidskriftsartikel (refereegranskat)abstract
- Studies that address fi sh welfare before slaughter have concluded that many of the traditional systems used to stun fi sh including CO 2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char ( Salvelinus alpinus ) stunned with CO 2 or electricity. Exposure to water saturated with CO 2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fi sh exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fi sh to recover from electrical stunning, whereas fi sh stunned with CO 2 did not recover. Despite this, the electrically stunned fi sh had more than double the plasma levels of cortisol compared with fi sh stunned with CO 2 . This result is surprising considering that the behavioural reactions were much more pronounced following CO 2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.
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| 13. |
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| 14. |
- Hinchcliffe, James, 1992, et al.
(författare)
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Aquafeed ingredient production from herring (Clupea harengus) by-products using pH-shift processing: Effect from by-product combinations, protein solubilization-pH and centrifugation force
- 2019
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Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401. ; 247, s. 273-284
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Tidskriftsartikel (refereegranskat)abstract
- There is a strong need in animal production for sustainable protein sources used in feed. The aim of the present study was to evaluate the potential of the pH-shift process as a method to concentrate proteins from complex bone-rich herring (Clupea harengus) by-products. By-product parts (frame, head, guts), protein solubilization pH (pH 2.8 or 11.3) and separation g-force (800 or 8000 g) were varied. The findings revealed that protein recovery yields of up to 60% were obtained and that higher protein yield was obtained from the alkaline than the acid process. By-product part and g-force had no significant impact on protein yield. Protein levels reached in the concentrates were 75–80 % (dw basis). Protein concentrates contained a similar amino acid profile as have been reported for fishmeal, with ~40% essential amino acids and up to 7.8% and 2.8% of lysine and methionine. Residual levels of LC n-3 PUFA as well as calcium, magnesium, potassium and phosphorous were also found in the produced protein concentrates which could be an added value. Acid produced concentrates were particularly high in calcium potassium and phosphorous. Provided a careful evaluation, the pH-shift process could become a successful alternative to classic fish meal production for increasing the use of fish by-products for production of protein ingredients for feed. © 2018 Elsevier B.V.
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| 15. |
- Huyben, David, et al.
(författare)
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Haematological and intestinal health parameters of rainbow trout are influenced by dietary live yeast and increased water temperature
- 2019
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Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 89, s. 525-536
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Tidskriftsartikel (refereegranskat)abstract
- Live yeast may be a sustainable protein source in salmonid diets while exhibiting a probiotic effect to counteract environmental stressors, such as increased water temperature that is being exacerbated by climate change. The objective of this study was to evaluate the effects of feeding a high dietary inclusion of live yeast and increased water temperature on growth, haematological and intestinal physiology of rainbow trout. For six weeks, 129 g fish in 16 tanks (n = 4) were fed either a diet based on fishmeal or based on live yeast (214 g kg −1 of diet or 7.6 log CFU g −1 of Saccharomyces cerevisiae) that replaced 40% of fishmeal protein while fish were reared in water temperatures of either 11 °C (cold) or 18 °C (warm). Fish weights, caudal blood and proximal and distal intestines were collected and analysed. Fish fed live yeast resulted in reduced growth (SGR and WG) and higher FCR, while growth in cold and warm water was similar despite differences in TGC. However, increased mortality, plasma cortisol, and intestinal oedema and villous damage indicated fish reared in warm water were subjected to chronic stress. Temperature had a significant effect on haematocrit and red blood cell counts that resulted in significantly higher haemoglobin levels in fish kept in warm water attributed to an elevated oxygen demand. In the proximal intestine, increased temperature resulted in reduced expression of pro-inflammatory cytokines, e.g. TNFα and IL8, that were further reduced in fish fed live yeast. In addition, feeding live yeast reduced gene expression of CLD6 involved in gut barrier function, which suggests that the level of yeast was too high and masked any beneficial effects on fish health. In conclusion, feeding a high inclusion of live yeast reduced fish growth and expression of intestinal genes, while increasing the temperature from 11 to 18 °C subjected fish to chronic stress that restricted growth, suppressed innate immunity and induced intestinal damage. Replacing 40% of fishmeal protein with live yeast did not counteract negative effects caused by increased temperature, thus alternative strategies need to be explored and implemented to protect the growth and health of rainbow trout from seasonal and long-term rises in water temperature. © 2019
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| 16. |
- Jin, Chunsheng, et al.
(författare)
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Atlantic Salmon Carries a Range of Novel O-Glycan Structures Differentially Localized on Skin and Intestinal Mucins
- 2015
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 14:8, s. 3239-3251
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Tidskriftsartikel (refereegranskat)abstract
- Aquaculture is a growing industry, increasing the need for understanding host-pathogen interactions in fish. The skin and mucosal surfaces, covered by a mucus layer composed of mucins, is the first point of contact between fish and pathogens. Highly O-glycosylated mucins have been shown to be an important part of the defense against pathogens, and pathogens bind to host surfaces using lectin-like adhesins. However, knowledge of piscine O-glycosylation is very limited. We characterized mucin O-glycosylation of five freshwater acclimated Atlantic salmon, using mass spectrometry. Of the 109 O-glycans found, most were sialylated and differed in distribution among skin, pyloric ceca, and proximal and distal intestine. Skin O-glycans were shorter (2-6 residues) and less diverse (33 structures) than intestinal O-glycans (2-13 residues, 93 structures). Skin mucins carried O-glycan cores 1, 2, 3, and 5 and three types of sialic acids (Neu5Ac, Neu5Gc, and Kdn) and had sialyl-Tn as the predominant structure. Intestinal mucins carried only cores 1, 2, and 5, Neu5Ac was the only sialic acid present, and sialylated core S was the most dominant structure. This structural characterization can be used for identifying structures of putative importance in host-pathogen interactions for further testing in biological assays and disease intervention therapies.
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| 17. |
- Knutsen, H. R., et al.
(författare)
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Fish welfare, fast muscle cellularity, fatty acid and body-composition of juvenile spotted wolffish (Anarhichas minor) fed a combination of plant proteins and microalgae (Nannochloropsis oceanica)
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 506, s. 212-223
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Tidskriftsartikel (refereegranskat)abstract
- Spotted wolffish (Anarhichas minor) is a promising candidate for diversification of cold-water aquaculture. An increased knowledgebase is needed concerning the capacity of spotted wolffish to utilize a variety of feed ingredients such as microalgae and terrestrial plants. The aim of the study was therefore to investigate the effect of incorporating graded levels of microalgae (Nannochloropsis oceanica) on fish welfare indicators (growth, hepasomatic index, hematological parameters), fast muscle cellularity, chemical and fatty acid composition. Three isonitrogenous and isocaloric diets were formulated; one control diet (0% N. oceanica) and two diets with low (7.5% N. oceanica) and high (15% N. oceanica) levels of microalgae replacing fishmeal and wheat in the diets. After 12 weeks of feeding, the fish showed low growth compared to previous wolffish studies (0.26% SGR). However, this effect was not treatment dependent as there were no differences in growth or fast muscle cellularity among the three treatment groups and hematological parameters showed no indications of stress in the fish fed microalgae. Hepatosomatic index decreased over the course of the experiment for all treatment groups; a significantly larger reduction was noted in the algae-fed fish compared to the control. The omega-3 fatty acid EPA increased in the whole body of the fish fed diets containing microalgae. The results suggest that spotted wolffish has potential to utilize inclusions of up to 15% of the microalgae N. oceanica.
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| 18. |
- Padra, János T, et al.
(författare)
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Aeromonas salmonicida Growth in Response to Atlantic Salmon Mucins Differs between Epithelial Sites, Is Governed by Sialylated and N-Acetylhexosamine-Containing O-Glycans, and Is Affected by Ca2
- 2017
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 85:8
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Tidskriftsartikel (refereegranskat)abstract
- Aeromonas salmonicida causes furunculosis in salmonids and is a threat to Atlantic salmon aquaculture. The epithelial surfaces that the pathogen colonizes are covered by a mucus layer predominantly comprised of secreted mucins. By using mass spectrometry to identify mucin glycan structures with and without enzymatic removal of glycan residues, coupled to measurements of bacterial growth, we show here that the complex Atlantic salmon intestinal mucin glycans enhance A. salmonicida growth, whereas the more simple skin mucin glycans do not. Of the glycan residues present terminally on the salmon mucins, only N-acetylglucosamine (GlcNAc) enhances growth. Sialic acids, which have an abundance of 75% among terminal glycans from skin and of <50% among intestinal glycans, cannot be removed or used by A. salmonicida for growth-enhancing purposes, and they shield internal GlcNAc from utilization. A Ca2+ concentration above 0.1 mM is needed for A. salmonicida to be able to utilize mucins for growth-promoting purposes, and 10 mM further enhances both A. salmonicida growth in response to mucins and binding of the bacterium to mucins. In conclusion, GlcNAc and sialic acids are important determinants of the A. salmonicida interaction with its host at the mucosal surface. Furthermore, since the mucin glycan repertoire affects pathogen growth, the glycan repertoire may be a factor to take into account during breeding and selection of strains for aquaculture.
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| 19. |
- Padra, János T, et al.
(författare)
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Fish pathogen binding to mucins from Atlantic salmon and Arctic char differs in avidity and specificity and is modulated by fluid velocity
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- Disease outbreaks are limiting factors for an ethical and economically sustainable aquaculture industry. The first point of contact between a pathogen and a host occurs in the mucus, which covers the epithelial surfaces of the skin, gills and gastrointestinal tract. Increased knowledge on host-pathogen interactions at these primary barriers may contribute to development of disease prevention strategies. The mucus layer is built of highly glycosylated mucins, and mucin glycosylation differs between these epithelial sites. We have previously shown that A. salmonicida binds to Atlantic salmon mucins. Here we demonstrate binding of four additional bacteria, A. hydrophila, V. harveyi, M. viscosa and Y. ruckeri, to mucins from Atlantic salmon and Arctic char. No specific binding could be observed for V. salmonicida to any of the mucin groups. Mucin binding avidity was highest for A. hydrophila and A. salmonicida, followed by V. harveyi, M. viscosa and Y. ruckeri in decreasing order. Four of the pathogens showed highest binding to either gills or intestinal mucins, whereas none of the pathogens had preference for binding to skin mucins. Fluid velocity enhanced binding of intestinal mucins to A. hydrophila and A. salmonicida at 1.5 and 2 cm/s, whereas a velocity of 2 cm/s for skin mucins increased binding of A. salmonicida and decreased binding of A. hydrophila. Binding avidity, specificity and the effect of fluid velocity on binding thus differ between salmonid pathogens and with mucin origin. The results are in line with a model where the short skin mucin glycans contribute to contact with pathogens whereas pathogen binding to mucins with complex glycans aid the removal of pathogens from internal epithelial surfaces.
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| 20. |
- Powell, Adam, 1981, et al.
(författare)
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Comparative survival and growth performance of European lobster larvae, Homarus gammarus, reared on dry feed and conspecifics
- 2017
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Ingår i: Aquaculture Research. - : Hindawi Limited. - 1355-557X .- 1365-2109. ; 48:10, s. 5300-5310
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Tidskriftsartikel (refereegranskat)abstract
- A bottleneck of crustacean larval culture concerns nutrition and associated cannibalism in communal rearing systems, which impact on larval survival, development and growth. For early stage European lobster, Homarus gammarus larvae, feeding ecology and body composition is largely unknown. We initiated four progressive feeding experiments (novel feed types, feeding regime and feed size) on growth and survival, to inform and update husbandry protocols. Performance of larvae offered a dry commercial feed was not significantly different compared to a conventional wet plankton feed of the same ration and size grade (both within 600-1000 µm). Further experiments found that the same ration of dry feed offered 6 times daily improved development and growth, over the conventional regime of 3 times daily. Small grade dry feed (particles 250-360 µm) improved larval performance compared to a larger feed (360-650 µm). Larvae were also fed different proportions of dry feed and/or conspecifics in both communal and individual rearing systems (the latter preventing cannibalism via segregation). Individually reared larvae, fed only dead conspecifics, displayed the greatest survival (80%) to post larvae. This underlines the impact of cannibalism on survival and nutrition in H. gammarus larviculture. A final experiment analysed H. gammarus zoea 1 composition, identifying deficiencies in ash and carbohydrate in lobster feeds. This suggests a need for a species specific, formulated dry feed for H. gamarus larviculture. Our research represents the first investigation of H. gammarus larval composition and dietary requirements, and highlights decreased growth potential associated with providing nutrition solely from generic commercial feed.
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| 21. |
- Rosengren, Malin, 1982, et al.
(författare)
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The brain-gut axis of fish: Rainbow trout with low and high cortisol response show innate differences in intestinal integrity and brain gene expression
- 2018
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 257, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Inc. In fish, the stress hormone cortisol is released through the action of the hypothalamic pituitary interrenal axis (HPI-axis). The reactivity of this axis differs between individuals and previous studies have linked this to different behavioural characteristics and stress coping styles. In the current study, low and high responding (LR and HR) rainbow trout in terms of cortisol release during stress were identified, using a repeated confinements stress test. The expression of stress related genes in the forebrain and the integrity of the stress sensitive primary barrier of the intestine was examined. The HR trout displayed higher expression levels of mineralocorticoid and serotonergic receptors and serotonergic re-uptake pumps in the telencephalon during both basal and stressed conditions. This confirms that HPI-axis reactivity is linked also to other neuronal behavioural modulators, as both the serotonergic and the corticoid system in the telencephalon are involved in behavioural reactivity and cognitive processes. Involvement of the HPI-axis in the brain-gut-axis was also found. LR trout displayed a lower integrity in the primary barrier of the intestine during basal conditions compared to the HR trout. However, following stress exposure, LR trout showed an unexpected increase in intestinal integrity whereas the HR trout instead suffered a reduction. This could make the LR individuals more susceptible to pathogens during basal conditions where instead HR individuals would be more vulnerable during stressed conditions. We hypothesize that these barrier differences are caused by regulation/effects on tight junction proteins possibly controlled by secondary effects of cortisol on the intestinal immune barrier or differences in parasympathetic reactivity.
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| 22. |
- Sillanpaa, J. K., et al.
(författare)
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Calcium mobilisation following shell damage in the Pacific oyster, Crassostrea gigas
- 2016
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Ingår i: Marine Genomics. - : Elsevier BV. - 1874-7787. ; 27, s. 75-83
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Tidskriftsartikel (refereegranskat)abstract
- Shell growth of oysters requires calcium uptake from the environment and transport to the area of shell formation. A shell regeneration assay in combination with radiolabelled calcium was used to investigate uptake and distribution of calcium to different tissues and hemolymph fractions in Pacific oysters, Crassostrea gigas (Bivalvia, Ostreoida). Oysters were notched at the shell margin and subsequently sampled for hemolymph and grading of shell regeneration during a two week experimental period. Half of the oysters were additionally exposed to Ca-45 and sampled for hemolymph and tissues. Total plasma calcium concentrations increased in notched oysters compared to controls on 1, 2 and 7 days after notching. A decrease in plasma calcium levels was apparent on day 4, for both total and ionic calcium. The shell regeneration assay in the notched oysters resulted in a visible deposition of CaCO3 onto the regenerate from day 7 onwards. This was coinciding with an increased uptake of total calcium on days 11 and 14 as well as free, i.e. ionic and ligand-bound calcium, on day 14. At day 1, notching also increased calcium uptake into the mantle tissues, in areas above the notch and near the hinge. During the experiment, both the total hemocyte count and the number of granulocytes increased in notched compared to control oysters. The present study suggests that induced shell damage results in a dynamic regulation of the calcium uptake from the environment and the distribution of calcium within the body, starting directly after notching. Increases in both total calcium concentrations and uptake rates coincided with the visible depositions of CaCO3 on the regenerate shell. C. gigas was found to transport calcium mainly in the ionic form in the hemolymph, with only minor parts being bound to proteins or smaller ligands. Hemolymph measurement also revealed that C. gigas is able to regulate the extracellular concentrations of calcium and potassium. The changes in plasma calcium concentrations and speciation, concomitant with increases in granulocytes indicate that multiple calcium transport processes are activated after induced shell damage.
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| 23. |
- Sillanpää, Kirsikka, et al.
(författare)
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Calcium transfer across the outer mantle epithelium in the Pacific oyster, Crassostrea gigas
- 2018
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1891
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Tidskriftsartikel (refereegranskat)abstract
- Calcium transport is essential for bivalves to be able to build and maintain their shells. Ionized calcium (Ca2þ) is taken up from the environment and eventually transported through the outer mantle epithelium (OME) to the shell growth area. However, the mechanisms behind this process are poorly understood. The objective of the present study was to characterize the Ca2þ transfer performed by the OME of the Pacific oyster, Crassostrea gigas, as well as to develop an Ussing chamber technique for the functional assessment of transport activities in epithelia of marine bivalves. Kinetic studies revealed that the Ca2þ transfer across the OME consists of one saturable and one linear component, of which the saturable component fits best to Michaelis – Menten kinetics and is characterized by a Km of 6.2 mM and a Vmax of 3.3 nM min21. The transcellular transfer of Ca2þ accounts for approximately 60% of the total Ca2þ transfer across the OME of C. gigas at environmental Ca2þ concentrations. The use of the pharmacological inhibitors: verapamil, ouabain and caloxin 1a1 revealed that voltage-gated Ca2þ-channels, plasma-membrane Ca2þ-ATPase and Naþ/Ca2þ-exchanger all participate in the transcellular Ca2þ transfer across the OME and a model for this Ca2þ transfer is presented and discussed. © 2018 The Author(s) Published by the Royal Society. All rights reserved.
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| 24. |
- Skogh, Carl-Johan, 1970, et al.
(författare)
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Ecoestrian
- 2017
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Ingår i: Lövsta Future Challenge – Miljösmart Hinder.
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- The Ecoestrian jumping obstacle was a collaboration between four senior researchers; Maria Sundin (Senior Lecture at the department of Physics, University of Gothenburg), Angela Wulff (Professor at the Biological and Environmental Sciences, University of Gothenburg), Kristina Sundell (Professor at the Biological and Environmental Sciences, University of Gothenburg) and Ingrid Martins Holmberg (Senior Lecture at the Department of Conservation, University of Gothenburg), Arja Källbom (Building Conservator) and Carl-Johan Skogh (Senior Lecture in Design at the Department of design, Academy of Design and Crafts, University of Gothenburg). Thru the project leader Maria Sundin and her fellow partners, all with an interest in the field of equestrian culture, we got invited to participate in the Lövsta Future Challenge competition (www.lovstafuturechallange.se). The task was to develop and present a sustainable jumping obstacle that would be presented and used at the Gothenburg Horse Show 2017 (www.gothenburghorseshow.com). By mixing recycled material with new research of oyster based composite material and natural dying the design solution provided a new way of presenting and constructing jumping obstacle in a professional setting. The name “Ecoestrian” became as a word game between the words “ecologic” and “equestrian”. During 2017 the project has developed and was presented with a new design solution as “the Ecoestrian Herald” at the Longines FEI European Championship in Gothenburg.
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| 25. |
- Strand, Helena, et al.
(författare)
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Etablera och utveckla vattenbruk i Sverige: Vattenbruksentreprenörers syn på utmaningar och lösningar.
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den här rapporten redovisar resultaten från en studie genomförd av SWEMARC, the Swedish mariculture research center, som är ett forskningscentrum för vattenbruk vid Göteborgs universitet. Studiens syfte har varit att synliggöra viktiga frågor eller problem som svenska vattenbruksentreprenörer upplever och ställs inför i sina ambitioner att starta upp, driva eller utveckla sitt vattenbruk, men också vilka behov av stöd som finns för att övervinna dem. Utgångspunkt för studien har varit att följa upp en enkät genomförd av SWEMARC i samband med en utbildning/kurs i januari 2017 på temat ”Hur startar man en vattenbruksverksamhet – fokus på tillstånd och miljöfrågor”, där en grupp vattenbruksentreprenörer fick svara på ett antal frågor gällande sina planer på att etablera eller expandera sitt vattenbruk. Genom semistrukturerade intervjuer har vi nu, ett år senare, följt upp entreprenörernas arbete med sina verksamheter med fokus på tillstånd och tillståndsprocesser; vilka viktiga frågor och problem har man stött på och hur man löst problemen? Om inte, vilka möjliga lösningar finns? Resultaten från studien visar att majoriteten av entreprenörerna arbetat aktivt för att driva vidare och genomföra sina planer på att etablera eller utöka sina vattenbruksanläggningar, dock med olika resultat och framgång. I detta sammanhang kan konstateras att etablering och utveckling av vattenbruk i Sverige tar tid. Kopplat till entreprenörernas arbete under det gångna året, men också utifrån tidigare erfarenheter, utkristalliseras en rad frågor och problem som innefattar: placering, kontakt med myndigheter och tillståndskrav samt att ett flertal tillstånd också är tidsbegränsade, utökning av vattenbruksverksamheten och behovet av tydliga besked, förlegad lagstiftning, möjligheten att söka bidrag, handläggningstider, skillnader i tolkningar och bedömningar men även bristande kunskap om vattenbruk. Utifrån detta beskrivs också vad entreprenörerna ser för behov för att övervinna problemen eller hur vissa frågor skulle kunna lösas, vilket bl.a. inkluderar tydligare platshänvisningar och tillgänglighet till information och data. Vidare skulle arbetet med tillståndsansökningar och kontakten med, men även samordning mellan myndigheter kunna förenklas om ansvar för vattenbruket fanns samlat hos en och samma myndighet. En viktig förutsättning för entreprenörerna är också att öka förutsägbarheten och tydligheten när det gäller exempelvis frågor kring etablering eller utökning av verksamheten. En central fråga kan då vara att höja kunskapsnivå och kompetens kring vattenbruk inom myndigheter. Det kan även vara att vattenbruksnäringens mångfald bättre speglas i regelverken, vilka behöver ses över så att bättre hänsyn tas till dagens teknik och behov. Studien belyser en rad viktiga frågor och behov att hantera för att möjliggöra utveckling av svenskt vattenbruk utifrån entreprenörers perspektiv och erfarenheter. Flertalet av teman som framkommit skiljer sig inte nämnvärt från utmaningar som tidigare diskuterats inom sektorn, vilket understryker behovet av fortsatt förändringsarbete men även ytterligare insatser och åtgärder.
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