Search results for " Trout"
showing 10 items of 157 documents
Quantitative structure-activity relationships for the toxicity of organophosphorus and carbamate pesticides to the Rainbow trout Onchorhyncus mykiss.
2006
This study has investigated the development of quantitative structure-activity relationships (QSARs) for the toxicity to rainbow trout Onchorhyncus mykiss Walbaum of 75 organophosphorus and carbamate pesticides. The toxicity data were obtained from an openly available toxicological database and were selected to be representative of a single endpoint. A large number of physicochemical and structural descriptors were calculated for the pesticides. QSAR models were developed using multiple linear regression and partial least-squares analyses. Following the removal of a small number of outliers, predictive QSARs were developed on small numbers of mechanistically relevant descriptors. Applying m…
Disappearance of malachite green residues in fry of rainbow trout (Oncorhynchus mykiss) after treatment of eggs at the hatching stage
2009
Abstract The disappearance of malachite green (MG) residues was determined in fry of rainbow trout (Oncorhynchus mykiss) after six repeated treatments of the eggs at the hatching stage with MG oxalate at exposure levels of 1, 3 and 6 mg l− 1 for 30 min. Fry samples were taken from newly hatched fry (0 days post-hatch, d.p.h.) and at regular time intervals at 16, 31, 43, 57 and 96 d.p.h. The residues of MG and its major metabolite, leucomalachite green (LMG), were found to accumulate in the fry after MG treatments of eggs, with the highest residue levels being determined in the newly hatched fry. After exposures of 3 mg l− 1 MG, mean concentrations of 1170 ± 106 µg kg− 1 and 276 ± 38.6 µg kg…
Maternal effects in vulnerability to eye-parasites and correlations between behavior and parasitism in juvenile Arctic charr
2017
Hatchery-reared fish show high mortalities after release to the wild environment. Explanations for this include potentially predetermined genetics, behavioral, and physiological acclimation to fish farm environments, and increased vulnerability to predation and parasitism in the wild. We studied vulnerability to Diplostomum spp. parasites (load of eye flukes in the lenses), immune defense (relative spleen size) and antipredator behaviors (approaches toward predator odor, freezing, and swimming activity) in hatchery-reared juvenile Arctic charr (Salvelinus alpinus) using a nested mating design. Fish were exposed to eye-fluke larvae via the incoming water at the hatchery. Fish size was positi…
First description of non-motile Yersinia ruckeri serovar I strains causing disease in rainbow trout, Oncorhynchus mykiss (Walbaum), cultured in Spain.
2006
Yersinia ruckeri, the causal agent of enteric redmouth (ERM) disease, was isolated from epizootics that occurred in different Spanish rainbow trout, Oncorhynchus mykiss (Walbaum), farms in which vaccination against ERM had been performed. In all episodes, the most pronounced clinical signs exhibited by affected fish were severe haemorrhages in the mouth, eyes and around the vent. The isolates were identified as Y. ruckeri serovar I by 16S rRNA sequencing together with serological tests. They lacked motility and lipase activity and thus belonged to biotype 2, and were highly virulent for juvenile rainbow trout, both by intraperitoneal injection (from 3.1 x 10(2) to 6.3 x 10(3) cfu per fish) …
Effects of progressive decrease of feeding frequency and re-feeding on production parameters, stomach capacity and muscle nutritional value in rainbo…
2020
Abstract Feeds and feeding constitute the major part of costs in intensive aquaculture. Any action to reduce feeding costs without negatively affecting fish production parameters and flesh quality would improve profitability of farming. Therefore, we studied the effects of feeding frequency on production parameters, stomach capacity and nutritional value of muscle in juvenile rainbow trout (Oncorhynchus mykiss) in an experiment with two stages. First, during the nine-week “starvation period” we fed rainbow trout (initial weight c. 40 g) with four different feeding protocols in an attempt to adapt the fish to a progressive decrease in the number of feeding days. During the second stage, a fo…
Effects of weekend starvation and the duration of daily feeding on production parameters of rainbow trout Oncorhynchus mykiss
2021
Abstract It would often be practical to starve the cultivated fishes over the weekends, e.g. to save in labour costs. We evaluated the possibility that domesticated juvenile rainbow trout (Oncorhynchus mykiss) could compensate for the lost growth of the 2-day weekend starvation by either hyperphagic response and/or by lower feed conversion ratio, compared to the fish fed every day in an 8-week experiment. Rainbow trout (initial weight c. 30 g, temperature 16 °C) starved during the weekends were able to increase feed intake during the weekdays clearly above the intake of the control fish after the first two weekends, also seen as an increase of the compensation coefficients over the last fou…
Identification and dose dependency of ibuprofen biliary metabolites in rainbow trout
2012
Abstract The biotransformation of the anti-inflammatory drug ibuprofen (IBF) was studied by exposing rainbow trout ( Oncorhynchus mykiss ) to IBF via intraperitoneal (i.p.) injection, and via water at four (0.17, 1.9, 13 and 145 μg L −1 ) exposure levels for 4 d. Following exposure, the bile was collected and analyzed by LC–MS/MS methods. The identification of the formed metabolites in i.p. injected fish bile was based on the exact mass determinations by a time-of-flight mass analyzer (Q–TOF–MS) and on the studies of fragments and fragmentation patterns of precursor ions by ion trap mass analyzer (IT-MS). In addition to unmetabolized IBF, several phase I and phase II metabolites were found …
Host specificity of Argulus coregoni (Crustacea: Branchiura) increases at maturation.
2007
SUMMARYWe tested the hypothesis that host specificity in ectoparasites does not depend exclusively on the features of the host but also on surrounding habitats, using 2 fish ectoparasites, Argulus coregoni and A. foliaceus (Crustacea: Branchiura), occurring sympatrically in Finnish lakes. Although these parasites are considered to be of low specificity, we found that the larger of the 2 species, A. coregoni developed a pronounced preference for salmonid hosts at the beginning of maturation (defined by the presence of copulating specimens). Argulus foliaceus infects a much wider range of fish hosts. We showed that specialization of A. coregoni on salmonids does not necessarily result from in…
Efficacy of emamectin benzoate in the control of Argulus coregoni (Crustacea: Branchiura) on rainbow trout Oncorhynchus mykiss.
2004
Efficacy of in-feed treatment with emamectin benzoate (Slice) for the control of ectoparasitic Argulus coregoni on rainbow trout Oncorhynchus mykiss was tested under laboratory and field conditions. In both experiments fish were fed with fish feed to deliver a therapeutic dose of 0 (control) or 50 microg emamectin benzoate kg(-1) d(-1) (treatment) for a period of 7 d. After 3 d of challenge with A. coregoni in the laboratory, the infestation level in treated fish was lower than that observed in the controls (p0.001). Efficacy of 100% against newly hatched A. coregoni metanauplii and adults and 80% against juveniles was observed. In the field, trial medication was undertaken at 2 sections on…
Epizootiology of protozoans in farmed salmonids at northern latitudes
1997
Abstract Protozoan ectoparasites were examined in a northern salmonid fish farm over a 10-year period, June 1984–May 1994, by the same researcher, with similar catching and sampling procedures throughout. Husbandry procedures remained constant during the study, e.g., fingerlings were kept in steel tanks and yearlings in both steel tanks and earth ponds. Ichthyobodo necator, Chilodonella hexasticha and Ichthyophthirius multifilurs infections were treated with formalin, salt and malachite green-formalin baths, respectively, whenever any parasites were found. Altogether 10 790 randomly sampled salmon (Salmo solar), sea trout (S. trutta m. trutta) and brown trout (S. trutta m. lacustris) were s…