Toxicity of the first ambimobile insecticide spirotetramat on juvenile rainbow trout (Oncorhynchus mykiss): A multibiomarker approach.

High flow generates significant alterations in downstream river reaches, resulting in physical condition changes in the downstream regions of the river such as water depth, flow velocity, water temperature and river bed. These alterations will lead to change in fish habitat configuration in the river. This paper proposes a model system to evaluate the high flow effects on river velocity, water depth, substrates changes, temperature distribution and consequently assess the change in spawning and juvenile rainbow trout (Oncorhynchus mykiss) habitats in the downstream region of the Glen Canyon Dam. Firstly, based on the 2 dimensional (2D) depth-averaged CFD (Computational Fluid Dynamics) model and heat transfer equation applied for simulation, three indices were simulated, namely depth, flow velocity and temperature distribution. Then, the spawning and juvenile fish preference curves were obtained based on these three indices and substrates distribution. After that, the habitat model was proposed and used to simulate the high flow effects on juvenile and spawning rainbow trout habitat structure. Finally, the weighted usable area (WUA) and overall suitability index (OSI) of the spawning and juvenile fish species were quantitatively simulated to estimate the habitat sensitivity. The results illustrate that the high flow effect (HFE) increased the juvenile rainbow trout habitat quality but decreased the spawning rainbow trout habitat quality. The juvenile trout were mainly affected by the water depth while the spawning rainbow trout were dominated by the bed elevation.

We tested the hypothesis that juvenile rainbow trout (Oncorhynchus mykiss) would select a temperature colder than their acclimation temperature (16 deg +/-1 deg C) to minimize postexhaustive exercise metabolic demands and enhance oxygen availability. After an initial 3-h exploratory period in a thermal gradient (6 degrees -25 degrees C), fish selected a temperature of approximately 14 degrees C and had a baseline exploratory swimming activity of approximately 60 cm min(-1). Subsequently, experimental (chased) fish were individually removed, exhaustively exercised for 1.5 min, and replaced. Both control (unchased) and experimental fish were allowed to explore the thermal gradient for another 2 h. Immediately after being chased, trout had a metabolic profile that was consistent with being exhausted; levels of plasma and muscle lactate were 4.38+/-0.25 mmol L(-1) and 28.0+/-2.0 mmol kg(-1), respectively, and levels of muscle glycogen, adenosine triphosphate, and phosphocreatine were 3.89+/-0.95, 4.23+/-0.62, and 3.07+/-0.73 mmol kg(-1), respectively. Although exploratory swimming activity of the chased fish was significantly lower (by 81%) as compared with control fish during the first 5 min postchase, differences in the mean, median, and mode values for selected temperatures during the next 2 h were neither large (<1 degrees C) nor significant (P>0.05). Contrary to our initial hypothesis, these findings suggest that juvenile rainbow trout do not select a colder temperature to decrease metabolic rate following exhaustive exercise. Instead, rainbow trout selected a temperature marginally cooler than their acclimation temperature (16 degrees C) regardless of whether they had been previously exhausted.

Progress toward understanding the bioaccumulation of perfluorinated alkyl acids

Previous research indicates that rainbow trout Oncorhynchus mykiss begin to exhibit health and welfare problems when cultured within water recirculating aquaculture systems (WRAS) operated at low exchange (6.7 days hydraulic retention time) and a mean feed loading rate of 4.1kgfeed/m3 daily makeup flow. These studies could not conclusively determine the causative agent of the health and welfare issues, but accumulation of mean nitrate nitrogen (NO3-N) to approximately 100mg/L was determined to be a potential cause of abnormal swimming behaviors such as “side swimming” and rapid swimming velocity. A subsequent controlled, 3-month study was conducted to determine if NO3-N concentrations of 80–100mg/L resulted in chronic health issues for rainbow trout. Equal numbers of rainbow trout (16.4±0.3g) were stocked within six replicated 9.5m3 WRAS. Three WRAS were maintained with a mean NO3-N concentration of 30mg/L (“low”) resulting from nitrification, and three WRAS were maintained with a mean concentration of 91mg/L (“high”) via continuous dosing of a sodium nitrate stock solution in addition to nitrification. All six WRAS were operated with equal water exchange (1.3 days mean hydraulic retention time) and mean feed loading rates (0.72kgfeed/m3 daily makeup flow), which provided enough flushing to limit the accumulation of other water quality concentrations. Rainbow trout growth was not significantly impacted by the high NO3-N treatment. Cumulative survival for fish cultured within the high NO3-N WRAS was lower and bordered statistical significance, which resulted in total rainbow trout biomass that was significantly lower for this group at study's end. In addition, a significantly greater prevalence of side swimming rainbow trout occurred in the high NO3-N treatment, as was observed during previous research. Swimming speeds were generally greater for rainbow trout cultured in the high NO3-N treatment, but were not always significantly different. Although most water quality variables were controlled, significant differences between treatments for the concentrations of other water quality parameters inhibited definitive conclusions regarding the effect of NO3-N. However, due to the unlikely toxicity of confounding water quality parameters, study results provided strong evidence that relatively low NO3-N levels, 80–100mg/L, were related to chronic health and welfare impacts to juvenile rainbow trout under the described conditions.

DAO Diseases of Aquatic Organisms Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials DAO 23:189-199 (1995) - doi:10.3354/dao023189 The esophagus/cardiac stomach region: site of attachment and internalization of infectious hematopoietic necrosis virus in challenged juvenile rainbow trout Oncorhynchus mykiss and coho salmon O. kisutch Helmick CM, Bailey JF, LaPatra S, Ristow S An anti-infectious hematopoietic necrosis virus (IHNV) nucleoprotein monoclonal antibody, 1NDW14D (IgG1), labeled with a streptavidin gold marker was utilized to monitor infection of juvenile rainbow trout and coho salmon with IHNV at the ultrastructural level. Juvenile fish were challenged with a virulent isolate of IHNV or mock-challenged with phosphate buffered saline. In both juvenile rainbow trout and coho salmon, the target area for infection by IHNV appeared to be the esophageal/cardiac stomach region (ECSR), particularly the mucus-secreting serous cardiac glands (MSSG). We previously found that, at the light microscopic and ultrastructural levels in rainbow trout, the MSSG form long continuous glands in association with the esophageal mucosa located opposite the swimbladder pneumatic duct. In contrast, the coho salmon MSSG bud from the esophageal mucosa, forming dense bodies located posterior to the pneumatic duct. With the aid of a 20 nm immunogold marker labeling the nucleoprotein of the virus, the progression of the infection was followed from the esophageal mucosa to the MSSG in both species. The immunogold marker was located in both the rainbow and coho salmon epithelial cells, which exhibited severe intercellular edema with separation of the mucosa at 24 h post challenge. The immunogold marker was also found in the MSSG of both species, with the rainbow trout exhibiting glandular cystic degeneration as early as 1 h post challenge, which further developed to a severe cystic degeneration by 24 h. The coho salmon exhibited a similar but milder reaction to the virus. In both species, the 24 h post mock-challenged MSSG exhibited no morphological changes. When the infection was monitored in the MSSG of both rainbow trout and coho salmon at 1 and 24 h post viral challenge, a statistically significant difference between the 2 time points was detected within each fish species, suggesting that replication occurred in the MSSG. In addition, a statistically significant difference was detected between fish species at both 1 and 24 h, indicating quantitatively that the virus is replicated more efficiently in the MSSG of rainbow trout than in the MSSG of coho salmon. Rhabdovirus . Portal of entry . Mucus-secreting cardiac glands (MSSG) . Rainbow trout . Coho Salmon Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in DAO Vol. 23, No. 3. Publication date: November 23, 1995 Print ISSN:0177-5103; Online ISSN:1616-1580 Copyright © 1995 Inter-Research.

Nowadays, the use of seaweed derivatives in aquaculture has drawn attention for their potential as an immunostimulant and growth promotor. The sulfated polysaccharide extracted (SPE ) from green (Caulerpa sp.; SPC) and brown (Padina sp.; SPP) seaweeds with two concentrations (0.05% and 0.1%); nominated in four groups: SPC0.05 , SPC0.1 , SPP0.05 , SPP0.1 and control group (free of SPE ) were used for juvenile rainbow trout (Oncorhynchus mykiss) diet. Fish (N: 150; 8.5 ± 0.2 g) were selected aleatory distributed in 15 circular tanks (triplicate for the group) and fed test diets for 56 days. The outcomes revealed that the supplementation of SPE up to 1 g kg-1 failed to show significant differences in the organosomatic indices as compared to the control group. The most inferior protein value of dress-out fish composition was observed in the fish fed the control diet, which was statistically lower than the SCP0.1 group (p < 0.05), while no significant difference was observed in other macronutrient composition among the treatments. Total monounsaturated fatty acid (MUFA) had lower trend in the carcass of fish fed SPE supplemented diets, so that lowest MUFA were observed in SPC0.05 group (p < 0.05; 25.22 ± 4.29%). The lowest value of docosahexaenoic acid was observed in the control diet compared to the SPE -supplemented diets (p < 0.05). The serum alternative complement pathway levels in all treatments tend to promote compared to the control treatment. A similar trend was observed for lysozyme activity. According to the results, the superoxide dismutase (SOD) value were highest in SPC0.05 and SPC0.1 compared to the other treatments (p < 0.05), while a further elevation of the SPE Padina sp. extracted level (SPP0.1 ) leads to a decrease in SOD value. Thiobarbituric acid reactive substances of plasma was indicated not to influence by sulfated polysaccharide extracts in the refrigerated storage. The lowest serum stress indicators were observed in fish fed SPP0.05 group postchallenge test. Taken together, our outcomes revealed that SPE of two species of seaweeds bestows benefits in some of the immunity and antioxidant system. Also, notable elevations in HUFA were observed in juvenile rainbow trout fed supplemented with SPE .

Reduction in swimming performance in juvenile rainbow trout (Oncorhynchus mykiss) following sublethal exposure to pyrethroid insecticides

BackgroundIn aquaculture, the secretions of cultured organisms contribute to the development of aquatic antibiotic resistance. However, the antibiotic-induced changes in fish feces remain poorly understood. This study aimed to assess the short-term dynamics of fecal microbiome and antibiotic resistance in juvenile rainbow trout (Oncorhynchus mykiss) upon antibiotic treatment and withdrawal period.MethodsFish were orally administered diets supplemented with oxytetracycline (OTC) or sulfadiazine/trimethoprim (SDZ/TMP) for 10 consecutive days, followed by a 25-day withdrawal period. Fecal samples were collected before antibiotic treatment (day 0), and at 1, 3, 7, and 10 days post antibiotic administration (dpa), as well as 1, 3, 7, 14, and 25 days post antibiotic cessation (dpc). The fecal microbiome community was profiled using both culture-dependent and -independent methods. The relative abundance of antibiotic resistance genes (ARGs) and the class 1 integron-integrase gene (intI1) in the feces were quantified using real-time PCR.ResultsAntibiotic treatment disrupted the fecal microbial communities, and this alteration persisted even after antibiotic cessation. Moreover, OTC treatment increased the relative abundance of tet genes, while sul and dfr genes increased in the SDZ/TMP-treated group. Notably, Flavobacterium, Pseudomonas, and Streptococcus exhibited a significant correlation with the abundance of ARGs, suggesting their potential role as carriers for ARGs.ConclusionThis study demonstrates the antibiotic-induced changes in the fecal microbiome and the increase of ARGs in rainbow trout feces. These findings provide novel insights into the dynamics of microbiome recovery post-antibiotic cessation and suggest that fish feces provide a non-invasive approach to predict changes in the fish gut microbiome and resistome.

Toxicity of atrazine and nonylphenol in juvenile rainbow trout (Oncorhynchus mykiss): Effects on general health, disease susceptibility and gene expression

Rotenone, a natural insecticide and piscicide, was shown to have an extremely small margin between no lethality (5.0 microg/L) and 100% mortality (6.6 microg/L) for static-renewal 96-hour toxicity tests with juvenile rainbow trout (Oncorhynchus mykiss). Dissolved organic carbon (DOC) at concentrations of 3.0 and 4.0 mg/L significantly increased the rotenone 96-hour LC(50) (median lethal concentration) from 5.80 microg/L (confidence interval (CI) 5.51 to 6.10) to 6.55 microg/L (CI 6.28 to 6.83) and 7.75 microg/L (CI 7.29 to 8.24), respectively, probably as a result of rotenone adsorption onto DOC, which decreased its bioavailability. Using concentrations of 0, 3.0, 4.0, and 5.0 microg/L rotenone and exposure periods of 2, 4, 6, 12, 16, 24, and 48 hours, the threshold concentration of rotenone for impairment of critical swimming performance (Ucrit) was 3.0 microg/L (P = 0.029), with no further impairment at higher concentrations and no time-dependent effect on Ucrit. Using continuous measures of oxygen uptake for 48 hours before and 48 hours during rotenone exposure (0, 1.5, 2.5, 3.0, and 3.5 microg/L), rotenone significantly decreased peak active oxygen uptake at all rotenone concentrations tested without affecting routine oxygen uptake. Fish were individually chased and then placed in rotenone concentrations of 0, 1.0, 3.0, 4.0, 5.0, and 6.0 microg/L to monitor initial postexercise oxygen uptake (Mo2Max) and excess postexercise oxygen consumption (EPOC) during a 40-minute recovery period. Rotenone significantly decreased Mo2Max (P = 0.002) after exposures to 4.0 and 5.0 microg/L, but not 6.0 microg/L, without affecting EPOC.

The accumulation of heat shock cognate (hsc)/heat shock protein (hsp) 70 was measured in gill and liver from juvenile and adult rainbow trout (Oncorhynchus mykiss) exposed to waterborne metals and/or fed a metal-contaminated diet. These experiments are part of a larger study in which physiological responses were documented in adult and juvenile rainbow trout after exposure to food-borne and/or waterborne metals for 21 d. Western blot analyses were used to measure the accumulation of hsp70 and hsc70. Hsc/hsp70 levels were significantly increased in gills of juveniles exposed to metals, in both water and food. The importance of metals in the diet as well as the water was confirmed for the juveniles. Significant increases in hsp/hsc70 could not be demonstrated in the adults.

Accumulation, depuration and hepatic mixed-function oxidase enzyme induction in juvenile rainbow trout and lake whitefish exposed to dietary 2,3,7,8-tetrachlorodibenzo -p-dioxin

Social status-dependent regulation and function of the somatotropic axis in juvenile rainbow trout

During the farming of juvenile rainbow trout (Oncorhynchus mykiss), losses can be very high. In aquaculture, various agents are used, such as copper, for the purpose of preventive action and prevention of the appearance of pathogens (ectoparasites, etc.). The aim of this study was to determine the effects of substrate-fixed copper microparticles on the growth and survival of juvenile rainbow trout (Oncorhynchus mykiss) up to the age of 5 months. The experiment was conducted in the Laboratory for Aquaculture of the Faculty of Agriculture, University of Banja Luka, for 142 days in flow aquariums with a 65 l/aquarium volume. The experiment was set up in two groups (150 units/group) with three replicates (50 units/replicate), a control group without copper microparticles (K) and a group with copper microparticles (Cu). The initial weight and total body length (mean ? SD) of rainbow trout in group K were 0.199 ? 0.008 g and 2.876 ? 0.036 cm, and in group Cu 0.197 ? 0.009 g and 2.893 ? 0.038 cm. The average total length and body weight of individuals from the K and Cu groups were similar (p &gt; 0.05). The differences in FCR, CF, SGR and TGC between group K and group Cu were not statistically significant (p &gt; 0.05). Survival of juvenile rainbow trout was high and it was 97.33% in group K and 96.00% in group Cu, and no statistically significant difference was found (p &gt; 0.05). The growth and survival of juvenile rainbow trout in the K and Cu groups were similar.

Rare earth elements (REEs) are contaminants of increasing interest due to intense mining activities for commercial purposes and ultimately released in the environment. We exposed juvenile rainbow trout (Oncorhynchus mykiss) to a representative mixture of the five most abundant REEs for 96 h at concentrations similar found in lakes contaminated by mining activities at 0.1, 1, 10, and 100X whereas the 1x mixture contained cerium (Ce, 280 μg/L), lanthanum (La, 140 μg/L), neodymium (Nd, 120 μg/L), praseodymium (Pr, 28 μg/L), and samarium (Sm, 23 μg/L). We investigated the expression of 14 genes involved in oxidative stress, DNA repair, tissue growth/proliferation, protein chaperoning, xenobiotic biotransformation, and ammonia metabolism in the liver. In addition, DNA damage, oxidative stress (lipid peroxidation or LPO), inflammation (cyclooxygenase or COX activity), detoxification mechanisms (glutathione-S-transferase activity or GST), and labile zinc were determined in gills. The data revealed that genes involved in oxidative stress-catalase (cat), heat shock proteins 70 (hsp70), and glutamate dehydrogenase (glud) were upregulated while glutathione S-transferase (gst) and metallothionein (mt) gene expressions were downregulated. The mixture was genotoxic and increased labile Zn in gills of exposed trout. These changes occurred at concentrations 600 times lower than the LC50 for this mixture indicating effects below the 1X concentration. Based on principal component analysis and concentration-dependent reponses, the following sublethal effects were considered the most important/significant: DNA strand breaks (genotoxicity), labile Zn, cat, gst, hsp70, sparc, mt, and glud. These effects of fish juveniles are likely to occur in environments under the influence of mining activities.