Oncorynchus Mykiss Research Articles

Whirling disease in the Crowsnest River: an emerging threat to wild salmonids in Alberta

We provide the first documented case of whirling disease (WD) impacts to wild, self-sustaining rainbow trout (RNTR, Oncorynchus mykiss) populations in Canada. Myxobolus cerebralis (Mc), the causative agent of WD, was first confirmed in Alberta in 2016. However, evidence of disease in local fish populations was unknown. Using a weight-of-evidence approach, we examined multiple parasite life cycle stages in the Crowsnest River, Alberta. Percentage of infected Tubifex tubifex worms actively shedding triactinomyxons (TAMs) exceeded known thresholds of Mc establishment and TAM densities instream exceeded thresholds known to cause ≥90% declines in RNTR populations. Mc was detected at 5 of 6 study sites in water, fish, and worms. Disease severity was highest in the lower watershed where 100% of sentinel fish tested positive for Mc 7 to 14 days post-exposure; up to 85% of wild fingerling RNTR showed clinical signs of disease and yearling trout were largely absent from the river suggesting reduced survival. Our findings indicate conditions necessary for outbreak of WD exist in Alberta, highlighting the need to consider this disease as an emerging threat to wild salmonid populations.

Fatty acid profile of Slovenian farmed rainbow trout

The present study was carried out to determine the fatty acid profile of rainbow trout (Oncorynchus mykiss) from three Slovenian fish farms; Zalog, Želimlje and Povodje. Fatty acids composition was determined on a gas chromatograph with a flame ionization detector (GC-FID). The results showed that farming conditions have a significant influence on the fatty acid composition of rainbow trout. The predominant saturated fatty acid (SFA) was palmitic acid, oleic acid was the main monounsaturated fatty acid (MUFA), while the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were the main long chain n-3 polyunsaturated fatty acids (n-3 PUFA). The percentage of DHA exceeded that of EPA in all rainbow trout samples studied. The n-6/n-3 ratio ranged from 0.89 to 1.54 and the PUFA/SFA ratio was between 1.81 and 2.36. In dorsal and ventral fillet parts, the content of most fatty acids was similar, exceptions were observed for some PUFAs; arachidonic acid, EPA and DHA

Landscape-scale social and ecological outcomes of dynamic angler and fish behaviours: processes, data, and patterns

The first relatively complete landscape-scale social–ecological system (SES) model of a recreational fishery was developed and ground-truthed with independent angling effort data. Based on the British Columbia multistock recreational fishery for rainbow trout (Oncorynchus mykiss), the model includes hundreds of individual lake fisheries, hundreds of thousands of anglers, originating from tens of communities, connected by complex road and trail networks, all distributed over a landscape of approximately half a million square kilometres. The approach is unique in that it incorporates realistic and empirically derived behavioural interactions within and among the three key components of the SES: angler communities, fish populations, and management policies. Current management policies were characterized and alternate policies assessed by simulation. We examined spatial patterns in ecological and social properties of the SES and used simulations to investigate the impacts of alternate management policies on these patterns. Simulation outcomes strongly depended on the spatial redistribution of anglers across the landscape, existing road networks, heterogeneity in angler behaviours, and the spatial pattern of fish population productivity.

REGULATION OF REPRODUCTIVE PROCESSES WITH DYNAMIC ENERGY BUDGETS.

1. The simple bioenergetic models in the family of Dynamic Energy Budget (DEB) consist of a small number of state equations quantifying universal processes, such as feeding, maintenance, development, reproduction and growth. Linking these organismal level processes to underlying suborganismal mechanisms at the molecular, cellular and organ level constitutes a major challenge for predictive ecological risk assessments. 2. Motivated by the need for process-based models to evaluate the impact of endocrine disruptors on ecologically relevant endpoints, this paper develops and evaluates two general modeling modules describing demand-driven feedback mechanisms exerted by gonads on the allocation of resources to production of reproductive matter within the DEB modeling framework. 3. These modules describe iteroparous, semelparous and batch-mode reproductive strategies. The modules have a generic form with both positive and negative feedback components; species and sex specific attributes of endocrine regulation can be added without changing the core of the modules. 4. We demonstrate that these modules successfully describe time-resolved measurements of wet weight of body, ovaries and liver, egg diameter and plasma content of vitellogenin and estradiol in rainbow trout (Oncorynchus mykiss) by fitting these models to published and new data, which require the estimation of less than two parameters per data type. 5. We illustrate the general applicability of the concept of demand-driven allocation of resources to reproduction as worked out in this paper by evaluating one of the modules with data on growth and seed production of an annual plant, the common bean (Phaseolis vulgaris).

Effects of the macroalga Sargassum angustifolium hot water extract on hematological parameters and immune responses in rainbow trout (Oncohrynchus mykiss) infected with Yersinia rukeri

Rainbow trout, Oncorynchus mykiss, specimens (n = 300, 6.43 ± 0.66 g) were fed with diets containing hot water extract (0.0, 50, 100, 200, and 400 mg kg−1 of a basal diet) of the brown alga Sargassum angustifolium within five triplicate groups (20 fish per group) for 8 weeks. Serum biochemical and hematological parameters, immune responses, and survival rates of the fish were analyzed at the end of growth performance period. The results showed the highest weight gain and specific growth rate in fish fed with dietary algal extract of 400 mg kg−1 after 8 weeks of feeding trial. Hemoglobin, hematocrit, red and white blood cells, total protein, and albumin were also highest in fish fed with 400-mg-kg−1 diet. Lysozyme activity and complement system showed no significant differences between the treatments. Exposure of the fish to the bacterial species, Yersinia rukeri, revealed that fish fed with the algal extracts displayed increased levels of blood and serum biochemical parameters, stronger immunity responses, and greater survival rates than the control group. According to the results, supplementing the diet of rainbow trout with hot water extract of S. angustifolium up to 400 mg kg−1 considerably affects the growth performance, immunity, and resistance to Y. rukeri.

Effects of fish meal replacement with meat and bone meal using garlic(Allium sativum) powder on growth, feeding, digestive enzymes and apparent digestibility of nutrients and fatty acids in juvenile rainbow trout (Oncorhynchus mykissWalbaum, 1792)

Effects of graded dietary levels of fish meal (FM) replacement with meat and bone meal (MBM) with garlic powder (G) or without garlic powder (WG) garlic powder were investigated on growth, digestive enzymes, apparent digestibility, body composition and fatty acid profile of juvenile rainbow trout (Oncorynchus mykiss; 8.26 ± 1.10 g). A total of eight dietary treatments were evaluated: control with garlic powder (0 MBM+G), 250 MBM+G, 450 MBM+G, and 650 MBM+G (g MBM/kg diet; treatments with garlic powder; G treatments), control without garlic powder (0 MBM), 250 MBM, 450 MBM and 650 MBM (g MBM/kg diet; treatments without garlic powder; WG treatments). Our results demonstrated that increased dietary content of MBM impaired growth and production performance, body composition, digestive enzyme activity, tissue fatty acid profile and overall digestibility. Addition of garlic powder was able to correct fish performance, body composition, enzyme activity and digestibility to some extent. Dietary supply of garlic resulted in increased digestive enzyme activity improving fish performance. The current results indicated that fish fed 650 g MBM/kg feed exhibited impaired growth that could be attributed to reduce digestibility of protein, fat, energy and dry matter, PUFAs and n-3 LC-PUFAs in muscle. We suggest that 450 g FM per kilo feed can be successfully replaced with MBM supplemented with 30 g garlic powder per kilo feed without impairing fish performance and physiology, however distorting tissue fatty acid composition resulting in lesser levels of n-3 LC-PUFAs compared to the 0 MBM+G diet.

Protein markers and mechanisms of Bacterial Cold Water Disease in Rainbow Trout (Oncorynchus mykiss) revealed using mass spectrometry proteomic analysis

Aquaculture is a rapidly expanding agricultural field, especially at the international level. One of the largest issues which arise from raising high densities of fish in a confined area is infection and rapid transmission of disease within the population. There are currently few federally approved pharmaceutical treatments for fish, making rapid and accurate diagnosis essential for maintaining healthy populations. The current study focuses on the infection of rainbow trout (Oncorynchus mykiss) by the gram‐negative bacteria Flavobacterium psychrophilum which manifests as Bacterial Cold Water Disease (BCWD). The approach involves examining the physiological effects of infection in these fish at the protein level. Using LC‐MS techniques, the majority of proteins in the kidney, spleen, plasma, and muscles at site of infection are analyzed for differential abundance between infected and control populations. Artificially infected cohorts are compared against fish taken from an active hatchery to determine whether lab results are reflected in a real‐world context. Sets of proteins which change in abundance as a response to BCWD infection make ideal candidates as bio‐markers which can be used in the development of diagnostic tools. This method also reveals the underlying mechanisms of the infection and response through gene ontology and pathway analysis. Plasma was found to have the greatest regulation in terms of significantly different protein abundance. For this reason and the relative ease of sampling plasma without fish sacrifice, plasma appears to the best tissue for diagnostic purposes. The greatest protein regulation in the plasma was seen in enzymes involved in glycolysis, actin cytoskeletal regulation, immune response, and oxidation‐reduction regulation.Support or Funding InformationSupported by NSF Grant IOB‐1355098

Thyroid active agents T3 and PTU differentially affect immune gene transcripts in the head kidney of rainbow trout (Oncorynchus mykiss)

In mammals, numerous reports describe an immunomodulating effect of thyroid-active compounds. In contrast, only few reports have been published on this subject in fish. We previously demonstrated that immune cells of rainbow trout (Oncorhynchus mykiss) possess thyroid hormone receptors (THRs) and that exposure of trout to the thyroid hormone 3,3′,5-triiodo-l-thyronine (T3) or the antithyroid drug propylthiouracil (PTU) alters immune cell transcript levels of THR and several immune genes. The present study aims to further characterize the immunomodulating action of thyroid-active compounds in trout immune cells. We report here the use of a custom-designed 60-mer oligo immune-targeted microarray for rainbow trout to analyze the gene expression profiles induced in the head kidney by T3 and PTU. Morphometric analyses of the thyroid showed that PTU exposure increased the size of the epithelial cells, whereas T3 induced no significant effects. Both T3 and PTU had diverse and partly contrasting effects on immune transcript profiles. The strongest differential effects of T3 and PTU on gene expressions were those targeting the Mitogen Associated Protein Kinase (MAPK), NFkB, Natural Killer (NK) and Toll-Like Receptor (TLR) pathways, a number of multipath genes (MPG) such as those encoding pleiotropic transcription factors (atf1, junb, myc), as well as important pro-inflammatory genes (tnfa, tnf6, il1b) and interferon-related genes (ifng, irf10). With these results we show for the first time in a fish species that the in vivo thyroidal status modulates a diversity of immune genes and pathways. This knowledge provides the basis to investigate both mechanisms and consequences of thyroid hormone- and thyroid disruptor-mediated immunomodulation for the immunocompetence of fish.

Adaptation of the fish juvenile growth test (OECD TG 215, 2000) to the marine species Dicentrarchus labrax

The OECD TG 215 method (2000) (C.14 method of EC Regulation 440/2008) was developed on the rainbow trout (Oncorynchus mykiss) to assess chronic toxicity (28d) of chemicals on fish juveniles. It contemplates to use other well documented species identifying suitable conditions to evaluate their growth. OECD proposes the European sea bass (Dicentrarchus labrax, L. 1758) as Mediterranean species among vertebrates recommended in the OECD guidelines for the toxicity testing of chemicals.In this context, our study is aimed to proposing the adaptation of the growth test (OECD TG 215, 2000) to D. labrax. For this purpose toxicity tests were performed with sodium dodecyl sulfate, a reference toxicant commonly used in fish toxicity assays. The main aspects of the testing procedure were reviewed: fish size (weight), environmental conditions, dilution water type, experimental design, loading rate and stocking density, feeding (food type and ration), test validity criteria. The experience gained from growth tests with the sea bass allows to promote its inclusion among the species to be used for the C.14 method.

Current State of Knowledge on Invasive and Alien Fauna of Nepal

This study produced a comprehensive list of introduced fauna of Nepal. Of the sixty four species of alien fauna reported, there were seven species of mammals with forty improved breeds of cow, buffalo, goat, sheep and pig, six species of birds with eight breeds of chicken and duck, nineteen species of fish, twenty two species of arthropods including one species of freshwater prawn and twenty one species of insects, nine species of molluscs and one species of platyhelminths. Among reported alien species Achatina fulica, Capra hircus, Clarius batrachus, Cyprinus carpio, Gambusia affinis, Oncorynchus mykiss, Oreochromis mossambicus, Oryctolagus cuniculus, Platydemus manokwari, and Sus scrofa are considered the worst species of the world and listed in ‘100 of the World’s Worst Invasive Alien Species’. The impacts of all these serious animals in Nepal are still to be studied but some problematic species of agricultural pests, freshwater habitat as well as livestock breeds are discussed in this paper.Journal of Institute of Science and Technology, 2015, 20(1): 68-81

Effects of diet composition and ultrasound treatment on particle size distribution and carbon bioavailability in feces of rainbow trout

The effect of a high and low non-starch polysaccharide diet (HNSP and LNSP diet) and ultrasound treatment on particle size distribution and carbon bioavailability in fecal waste of rainbow trout (Oncorynchus mykiss) was studied. Feces were collected from four flow-through fish tanks, two tanks fed the HNSP diet and two the LNSP diet. The collected feces were sonicated (disintegrated) in duplicate with high-intensity (0.6W/ml), low-frequency (f=20Hz) ultrasound at five different energy levels (0.6W/ml for 0, 0.25, 1, 4, and 16min). The particle size distribution of the treated feces samples was measured by wet sieving (1000, 500, 200, 100, 63, 36, 1.2μm screen size) and total suspended solids (TSS) measurement. Carbon bioavailability in sonicated fecal waste samples was determined with oxygen uptake rate (OUR) tests. The results showed that: (1) feces from the HNSP diet contained significant more particulate material and bigger particles; (2) carbon bioavailability was almost three times higher in untreated LNSP feces when compared with HNSP feces; (3) almost 50% of HNSP feces could have been recovered on a microscreen of 36μm after wet sieving, whereas it was only 10% for LNSP feces; (4) the production of small particles (1.2–36μm), which could pass a drum filter screen and potentially accumulate in RAS, was approximately 50g/kg feed, showing no significant differences between diets; (5) sonication increased fecal dry matter below 36μm (p=0.015), but it had no significant effect on the median particle size; (6) sonication increased carbon bioavailability with 7–10% for the HNSP feces (p=0.037); (7) fecal particles withstood up to 16min sonication at an intensity of 0.6W/ml and a frequency of 20Hz corresponding to specific energy input of 20,000kJ/kg DM without major changes in particle size distribution. The results of this study indicate that the applied ultrasound treatment of fecal waste is not an effective method to increase short-term carbon bioavailability.

Solid and suspended/dissolved waste (N, P, O) from rainbow trout ( Oncorynchus mykiss)

Quantifying aquaculture waste into different waste fractions will make it possible to design different treatment setups for obtaining specific cleaning objectives. The aim of this study was therefore to measure “all” solid and suspended/dissolved (i.e. unsedimented) waste from juvenile rainbow trout ( Oncorynchus mykiss) fed three commonly applied commercial diets, “all” waste referring to: total nitrogen (N), total ammonia nitrogen (TAN=NH 3-N+NH 4-N), total phosphorus (P), and organic matter characterized by the chemical oxygen demand (COD) and the biological oxygen demand after 5 days (BOD 5). Furthermore, it was hypothesized that solid COD waste can be calculated from undigested nutrients. Two experiments were carried out using a modified Guelph System. Nitrogen and phosphorus waste was derived from mass-balances based on all measured values in the first experiment. Apparent digestibility coefficients (ADCs) were used to calculate the solid amounts of undigested nutrients. These were subsequently used for calculating the solid COD output, verified by direct COD measurements. The output of solid and suspended/dissolved BOD 5 and COD was measured in the second experiment. There were just minor differences between the dietary treatment groups in the waste produced. On average, 48% of the ingested N was recovered in the water (TAN constituting 64–79% of this) and 7% in the solids. In comparison, 1% of the ingested P was recovered in the water and 43% in the solids. A breakpoint value of 5.6 g standardized available P kg − 1 dry feed was found, below which the dissolved P excretion was minimal and above which it increased rapidly. More COD was recovered as solid waste than as suspended/dissolved waste, while it was opposite for BOD 5. A BOD 5/COD ratio of 0.5 indicated that the suspended/dissolved waste was characterized by easily degradable organic matter, while a solid BOD 5/COD ratio of 0.2 indicated that this waste fraction contained high amounts of hard-to-degrade organic matter. Finally, the study showed that solid COD waste can be quite accurately calculated from the composition and content of undigested nutrients.

Toxicological and ecotoxic impact of secondary and tertiary treated sewage effluents

Secondary sewage effluents are discharged in significant quantities in aquatic environments delivering pollutants that were not removed during treatment; yet advanced treated effluents are not lacking of contaminants. In this study, biochemical biomarkers were measured in liver and kidney of rainbow trout ( Oncorynchus mykiss) exposed to unchlorinated, chlorinated and tertiary treated secondary sewage effluents. In addition, organic matter, nitrogen and suspended solids were assayed, while a common bioassay, Daphnia magna 21d reproduction test was also applied in order to examine potential relation between the performed bioassay and the biomarkers. Processes using oxidative conditions, such as ozonation and chlorination, resulted in significantly increased breeding rate (up to 74%) of the organism. Biomarkers measurements incorporated the determination of total glutathione (GSH), glutathione S-transferases (GST), glutathione peroxidase (GPX), lipid peroxidation (LPO) and an innovative biomarker in such applications, haem peroxidase. In general, the response of biomarkers was dependent upon the treatment method and it was tissue specific. Secondary effluents inhibited liver GST and haem peroxidase, while GSH levels and LPO were significantly provoked in liver. Ozonation provoked hepatic peroxidation, in terms of haem peroxidase and LPO, and GST; while the protective (to Reactive Oxidant Species – ROS) GSH was depleted, suggesting extended ROS attack to the organism. Similar response of biomarkers (but to a lesser extend) was observed after exposure of trout to effluents submitted to both coagulation and ozonation, emphasizing the significance of removing the residual organic matter by other methods than oxidative ones. Ozonation also enhanced renal LPO and GPX; however the former employment of coagulation limited the peroxidation phenomena. Chlorination mainly affected the levels of total GSH in both tissues.

Emergence of cold water strawberry disease of rainbow trout Oncorynchus mykiss in England and Wales: outbreak investigations and transmission studies

Cold water strawberry disease (CWSD), or red mark syndrome (RMS), is a severe dermatitis affecting the rainbow trout Oncorynchus mykiss. The condition, which presents as multifocal, raised lesions on the flanks of affected fish, was first diagnosed in Scotland in 2003 and has since spread to England and Wales. Results of field investigations indicated the condition had an infectious aetiology, with outbreaks in England linked to movements of live fish from affected sites in Scotland. Transmission trials confirmed these results, with 11 of 149 and 106 of 159 naive rainbow trout displaying CWSD-characteristic lesions 104 to 106 d after being cohabited with CWSD-affected fish from 2 farms (Farm B from England and Farm C from Wales, respectively). The condition apparently has a long latency, with the first characteristic lesions in the previously naive fish not definitively observed until 65 d (650 day-degrees) post-contact with affected fish. Affected fish from both outbreak investigations and the infection trial were examined for the presence of viruses, oomycetes, parasites and bacteria using a combination of techniques and methodologies (including culture-independent cloning of PCR-amplified bacterial 16S rRNA genes from lesions), with no potentially causative infectious agent consistently identified. The majority of the cloned phylotypes from both lesion and negative control skin samples were assigned to Acidovorax-like beta-Proteobacteria and Methylobacterium-like alpha-Proteobacteria.

The Candidate Gene, Clock, Localizes to a Strong Spawning Time Quantitative Trait Locus Region in Rainbow Trout

We applied a candidate gene mapping approach to an existing quantitative trait loci (QTL) data set for spawning date in rainbow trout (Oncorynchus mykiss) to ascertain whether these genes could potentially account for any observed QTL effects. Several genes were chosen for their known or suspected roles in reproduction, circadian, or circannual timing, including salmon-type gonadotropin-releasing hormone 3A and 3B (GnRH3A and GnRH3B), Clock, Period1, and arylalkylamine N-acetlytransferase-1 and -2 (AANAT-1 and AANAT-2). Genes were sequenced, and polymorphisms were identified in parents of two rainbow trout mapping families, one of which was used previously to detect spawn timing QTL. Interval mapping was used to identify associations between genetic markers and spawning date effects. Using a genetic map that was updated with 574 genetic markers (775 total), we found evidence for 11 significant or suggestive QTL regions. Most QTL were only localized within one of the parents; however, a strong QTL region was identified in both female and male parents on linkage group RT-8 that explained 20% and 50% of trait variance, respectively. The Clock gene mapped to this region. Period1 mapped to a region in the female parent associated with a marginal effect (P = .056) on spawn timing. Other candidate genes were not associated with significant QTL effects.

Antibody repertoire development in teleosts—a review with emphasis on salmonids and Gadus morhua L

The group of teleosts is highly diverse, comprising more than 23000 extant species. Studies of the teleost antibody repertoire have been conducted in many different species within different orders, though some species and families have been better characterised than others. The Atlantic cod ( Gadus morhua L.) and several species within the Salmoninae (e.g. Salmo salar and Oncorynchus mykiss) are among the best-studied teleosts in terms of the antibody repertoire. The estimated size of the repertoire, the organisation of immunoglobulin (IG) gene segments, the expressed IG repertoire, the IgM serum concentration, and the serum antibody responses reveal some fundamental differences between these species. The serum IgM concentration of G. morhua is some ten times higher than that of S. salar, though G. morhua is characterised as a ‘low’ (or ‘non’) responder in terms of specific antibody production. In contrast, an antibody response is readily induced in S. salar, although the response is strongly regulated by antigen induced suppression. The IGHD gene of G. morhua has a unique structure, while the IGHM and IGHD genes of S. salar have a characteristic genomic organisation in two parallel loci. In addition, salmonids, express a broad repertoire of IGH and IGI V-region gene segments, while a single V gene family dominates the expressed heavy and light chain repertoire of G. morhua. Little is known about the developing antibody repertoire during ontogeny, in different stages of B-cell maturation, or in separate B-cell subsets. Information on the establishment of the preimmune repertoire, and the possible role of environmental antigens is also sparse.

Effects of modified atmosphere and vacuum packaging on microbiological and chemical properties of rainbow trout ( Oncorynchus mykiss) fillets

Microbial (psychrotrophic, mesophilic aerobic bacteria and Enterobacteriacae counts), and chemical analysis [pH, total volatile bases nitrogen (TVB-N), lipid oxidation (Thiobarbituric acid reactive substance, TBARS)] of rainbow trout ( Oncorynchus mykiss) fillets in air (control), vacuum and modified atmosphere packaging (MAP) with various gas mixtures conditions at 4±1 °C were determined. The gas mixtures evaluated were 100% CO 2, 2.5% O 2+7.5% N 2+90% CO 2 and 30% O 2+30% N 2+40% CO 2. Psychrotrophic bacteria count was above 1×10 7 cfu/g on the 12th day in 100% CO 2. However; mesophilic bacteria count was below 1×10 6 cfu/g at the end of the 14-day storage period. Enterobacteriaceae count was significantly lower in samples packaged with MAP. Lipid oxidation increased rapidly after 6 days of storage in the samples containing 30% O 2. While minimum TBARS values were recorded in fillets containing 100% CO 2 and vacuumed fillets, the lowest TVB-N values were obtained in fillets with 100% CO 2.

Mortality of rainbow trout [Oncorynchus mykiss (Walbaum)] associated with freshwater dinoflagellate bloom [Peridinium polonicum (Woloszynska)] in a fish farm

Aquaculture ResearchVolume 33, Issue 2 p. 141-145 Mortality of rainbow trout [Oncorynchus mykiss (Walbaum)] associated with freshwater dinoflagellate bloom [Peridinium polonicum (Woloszynska)] in a fish farm J Roset, Corresponding Author J Roset Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainJ Roset, Centro de Investigación en Sanidad Animal, CISA-INIA. 28130 Valdeolmos, Madrid, España. E-mail: roset@inia.esSearch for more papers by this authorA Gibello, A Gibello Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorS Aguayo, S Aguayo Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainSearch for more papers by this authorL Domínguez, L Domínguez Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorM Álvarez, M Álvarez Departamento de Biología Ambiental, Centro de Ciencias Medioambientales, CSIC, Madrid, SpainSearch for more papers by this authorJ F Fernández-Garayzabal, J F Fernández-Garayzabal Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorA Zapata, A Zapata Departamento de Biología Celular (Morfología Microscópica), Facultad de Biología, UCM, SpainSearch for more papers by this authorM J Muñoz, M J Muñoz Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainSearch for more papers by this author J Roset, Corresponding Author J Roset Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainJ Roset, Centro de Investigación en Sanidad Animal, CISA-INIA. 28130 Valdeolmos, Madrid, España. E-mail: roset@inia.esSearch for more papers by this authorA Gibello, A Gibello Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorS Aguayo, S Aguayo Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainSearch for more papers by this authorL Domínguez, L Domínguez Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorM Álvarez, M Álvarez Departamento de Biología Ambiental, Centro de Ciencias Medioambientales, CSIC, Madrid, SpainSearch for more papers by this authorJ F Fernández-Garayzabal, J F Fernández-Garayzabal Departamento de Patologia Animal I, Facultad de Veterinaria, UCM, SpainSearch for more papers by this authorA Zapata, A Zapata Departamento de Biología Celular (Morfología Microscópica), Facultad de Biología, UCM, SpainSearch for more papers by this authorM J Muñoz, M J Muñoz Centro de Investigación en Sanidad Animal, CISA-INIA, Madrid, SpainSearch for more papers by this author First published: 28 April 2002 https://doi.org/10.1046/j.1365-2109.2002.00660.xCitations: 7Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume33, Issue2February 2002Pages 141-145 RelatedInformation

Bioavailability to juvenile rainbow trout (Oncorynchus mykiss) of retene and other mixed‐function oxygenase‐active compounds from sediments

Retene (7-isopropyl-1-methylphenanthrene) is a naturally formed polycyclic aromatic hydrocarbon (PAH) that causes teratogenicity in fish larvae and induction of cytochrome P450 (CYP1A) enzymes. Retene occurs at high concentrations (< or =3,300 microg/g dry wt) in surface sediments contaminated by resin acids from pulp mill effluents. To assess the environmental risks of retene, it is important to evaluate conditions affecting its bioavailability and accumulation by fish. Fingerling rainbow trout were exposed to retene-spiked or naturally contaminated sediments and sampled after 4 d to determine liver CYP1A activity and concentrations of retene metabolites in bile as indicators of retene accumulation. Industrially contaminated sediments collected near a bleached kraft pulp and paper mill discharging to Lake Saimaa, Finland, significantly induced trout liver CYP1A activity, indicating accumulation of arylhydrocarbon receptor (AhR)-active ligands. Bile of these fish contained retene metabolites, providing direct evidence that retene is bioavailable, presumably via desorption from sediments. Induction of CYP1A in fish exposed to sediments spiked with retene or benzo[k]fluoranthene supported this conclusion. While the extent of CYP1A induction by spiked sediments declined after storage (i.e., aging), a portion of the spiked PAHs remained bioavailable. However, retene was not the sole CYP1A inducer in industrially contaminated sediments, as shown by induction in fish injected with sediment extracts oxidized to remove labile PAHs but not persistent organochlorine compounds such as chlorinated dioxins and furans.

Inhibition of RNA synthesis differentially affects in vitro melatonin release from the pineal organs of ayu ( Plecoglossus altivelis) and rainbow trout ( Oncorhynchus mykiss)

The effects of actinomycin D (RNA synthesis inhibitor) and cycloheximide (protein synthesis inhibitor) on melatonin release from the cultured pineal organ of two teleosts with or without the circadian regulation of melatonin production (ayu Plecoglossus altivelis and rainbow trout Oncorynchus mykiss, respectively) were investigated. Actinomycin D decreased melatonin release from the pineal organ during the dark phase but there was a significant difference between the two species (22.2% for ayu and 59.1% for trout as compared with the respective control). This difference might be due to whether the circadian regulation via gene transcription of melatonin synthesis exists or not. On the other hand, cycloheximide decreased melatonin release to ~1% in both species, indicating that the fish pineal organ requires de novo protein synthesis to maintain rhythmic melatonin release.