Juvenile Rainbow Trout (juvenile + rainbow_trout)

Distribution by Scientific Domains


Selected Abstracts


Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I: Bioaccumulation parameters and evidence of bioisomerization

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006
Kerri Law
Abstract Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three diastereoisomers (,, ,, ,) of hexabromocyclododecane (C12H18Br6) via their diet for 56 d followed by 112 d of untreated food to examine bioaccumulation parameters and test the hypothesis of in vivo bioisomerization. Four groups of 70 fish were used in the study. Three groups were exposed to food fortified with known concentrations of an individual diastereoisomer, while a fourth group were fed unfortified food. Bioaccumulation of the ,-diastereoisomer was linear during the uptake phase, while the ,- and ,-diastereoisomers were found to increase exponentially with respective doubling times of 8.2 and 17.1 d. Both the ,- and the ,-diastereoisomers followed a first-order depuration kinetics with calculated half-lives of 157 ± 71 and 144 ± 60 d (±1 × standard error), respectively. The biomagnification factor (BMF) for the ,-diastereoisomer (BMF = 9.2) was two times greater than the ,-diastereoisomer (BMF = 4.3); the large BMF for the ,-diastereoisomer is consistent with this diastereoisomer dominating higher-trophic-level organisms. Although the BMF of the ,-diastereoisomer suggests that it will biomagnify, it is rarely detected in environmental samples because it is present in small quantities in commercial mixtures. Results from these studies also provide evidence of bioisomerization of the ,- and ,-diastereoisomers. Most importantly, the ,-diastereoisomer that was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish was bioformed from both the ,- and the ,-diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota. [source]


Reduced growth of rainbow trout (Oncorhynchus mykiss) fed a live invertebrate diet pre-exposed to metal-contaminated sediments

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2004
James A. Hansen
Abstract Juvenile rainbow trout (Oncorhynchus mykiss) were fed live diets of Lumbriculus variegatus cultured in metal-contaminated sediments from the Clark Fork River Basin (MT, USA), an uncontaminated reference sediment, or an uncontaminated culture medium. Fish were tested in individual chambers; individual growth as well as the nutritional quality and caloric value of each trout's consumed diet were determined. Growth was measured following 14, 28, 42, 56, and 67 d of exposure. A subset of fish was sampled at 35 d for whole-body metals. Metals (whole body, digestive tract, and liver) and histology were measured at the end of the test. We observed significant growth inhibition in trout fed the contaminated diets; growth inhibition was associated with reductions in conversion of food energy to biomass rather than with reduced food intake. Growth inhibition was negatively correlated with As in trout tissue residues. Histological changes in contaminated treatments included hepatic necrosis and degenerative alterations in gallbladder. The present study provides evidence that metal-contaminated sediments can pose a hazard to trout health through a dietary exposure pathway. [source]


Characterization of serum and mucosal antibody responses and relative per cent survival in rainbow trout, Oncorhynchus mykiss (Walbaum), following immunization and challenge with Flavobacterium psychrophilum

JOURNAL OF FISH DISEASES, Issue 12 2002
B R LaFrentz
Abstract Serum and mucosal antibody responses of juvenile rainbow trout, Oncorhynchus mykiss, were characterized by enzyme-linked immunosorbent assay (ELISA) following immunization with various preparations of formalin-killed Flavobacterium psychrophilum cells. The protective nature of these preparations was then determined by immunizing rainbow trout fry and challenging with the bacterium. Juvenile rainbow trout immunized intraperitoneally (i.p.) with formalin-killed F. psychrophilum emulsified with Freund's complete adjuvant (FCA), and i.p. with formalin-killed F. psychrophilum either with or without culture supernatant generated significant serum antibody responses by 6 and 9 weeks, respectively. Significant mucosal antibody responses were detected by 9 weeks only in fish immunized i.p. with killed F. psychrophilum/FCA. Following immunization and bacterial challenge of rainbow trout fry, protective immunity was conferred in F. psychrophilum/FCA and saline/FCA groups with relative per cent survival values of up to 83 and 51, respectively. Significant protection was not observed in treatment groups immunized by immersion or i.p. without adjuvant at the challenge doses tested. Results suggest that stimulation of non-specific immune factors enhances the ability of fish to mount a protective immune response, but specific antibody appears necessary to provide near complete protection. In this study, an ELISA was developed to monitor anti- F. psychrophilum antibody production in trout. The relationship of such responses to protective immunity suggests that future vaccination strategies against coldwater disease may require stimulation of both the innate and adaptive arms of the immune response. [source]


Effects of radio-transmitter antenna length on swimming performance of juvenile rainbow trout

ECOLOGY OF FRESHWATER FISH, Issue 4 2004
K. J. Murchie
Abstract,,, Technological advances have lead to the production of micro radio-transmitters capable of being implanted in fish as small as c. 5 g. Although the actual tags are small, transmitters are equipped with long antennas that can increase drag and tangle in debris. We examined the effects of radio-transmitter antenna length on the swimming performance of juvenile rainbow trout, Oncorhynchus mykiss, (N = 156, mean mass = 34 g, mean fork length = 148 mm). Although we tested a variety of different antenna lengths up to a maximum of 300 mm, only the longest antenna significantly impaired swimming performance relative to control fish (P < 0.001). There was no difference in swimming performance between the sham (surgery, but no transmitter) and the control fish (handled, but no surgery), suggesting that the surgical procedure itself did not negatively affect the fish. Regression analysis, however, indicated that there was a significant decrease in swimming performance associated with increased antenna length (R2 = 0.11, P < 0.001). In addition, when held in laboratory tanks, fish with the three longest antennas (150, 225 and 300 mm) frequently became entangled with the standpipe. We suggest that researchers, under the guidance of the tag manufacturer, trim antennas to the shortest possible length required to detect fish in their specific study area. Antenna length is clearly an important issue for small fish, especially for species that inhabit complex habitats where antennas may become entangled, and where fish must attain speeds near limits of their swimming capacity. Resumen 1. Los avances tecnológicos han llevado a producir micro radio-trasmisores capaces de ser implantados en peces de muy pequeño tamaño (,5 g). Aunque las marcas actuales son pequeñas, los trasmisores están equipados con antenas largas que pueden llegar a enredarse en los restos de vegetación. Examinamos los efectos de la longitud de la antena sobre la rutina natatoria de juveniles de Oncorhynchus mykiss (n = 156, peso medio = 34 g, longitud furcal media = 148 mm). 2. Aunque analizamos varias longitudes de antena, hasta 300 mm, solamente las de mayor longitud alteraron la rutina natatoria en relación a los peces control (P < 0.001). No hubo diferencia en la rutina natatoria entre individuos bajo cirugía pero sin trasmisores respecto de los individuos control (manipulados pero sin cirugía) lo que sugiere que los procedimientos de cirugía no afectaron negativamente a los peces. Sin embargo, análisis de regresión indicaron un declive significativo en la rutina natatoria asociado a la longitud de la antena (R2 = 0.11, P < 0.001). Además, al ser mantenidos en tanques, los individuos con las tres antenas mas largas (150, 225, y 300 mm) frecuentemente se enredaron con las tuberías. 3. Sugerimos a los investigadores que, bajo la dirección de los productores de marcas y antenas, consideren el uso de las antenas más pequeñas que permitan detectar a los peces en sus respectivas áreas de estudio. La longitud de la antena es una cuestión importante para los pequeños peces, especialmente para especies en hábitats complejos donde las antenas pueden llegar a enredarse y donde los peces pueden alcanzar velocidades casi al limite de su capacidad natatoria. [source]


Dietary accumulation of hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I: Bioaccumulation parameters and evidence of bioisomerization

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2006
Kerri Law
Abstract Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three diastereoisomers (,, ,, ,) of hexabromocyclododecane (C12H18Br6) via their diet for 56 d followed by 112 d of untreated food to examine bioaccumulation parameters and test the hypothesis of in vivo bioisomerization. Four groups of 70 fish were used in the study. Three groups were exposed to food fortified with known concentrations of an individual diastereoisomer, while a fourth group were fed unfortified food. Bioaccumulation of the ,-diastereoisomer was linear during the uptake phase, while the ,- and ,-diastereoisomers were found to increase exponentially with respective doubling times of 8.2 and 17.1 d. Both the ,- and the ,-diastereoisomers followed a first-order depuration kinetics with calculated half-lives of 157 ± 71 and 144 ± 60 d (±1 × standard error), respectively. The biomagnification factor (BMF) for the ,-diastereoisomer (BMF = 9.2) was two times greater than the ,-diastereoisomer (BMF = 4.3); the large BMF for the ,-diastereoisomer is consistent with this diastereoisomer dominating higher-trophic-level organisms. Although the BMF of the ,-diastereoisomer suggests that it will biomagnify, it is rarely detected in environmental samples because it is present in small quantities in commercial mixtures. Results from these studies also provide evidence of bioisomerization of the ,- and ,-diastereoisomers. Most importantly, the ,-diastereoisomer that was recalcitrant to bioisomerization by juvenile rainbow trout in this study and known to be the dominant diastereosiomer in fish was bioformed from both the ,- and the ,-diastereoisomers. To our knowledge, this is the first report of bioisomerization of a halogenated organic pollutant in biota. [source]


Estrogenicity in bile of juvenile rainbow trout as measure of exposure and potential effects of endocrine disruptors

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004
Ann-Sofie Allard
Abstract Estrogenicity in the bile of juvenile rainbow trout exposed to effluents from municipal sewage treatment plants and various industries was assayed by using a recombinant yeast strain containing the human estrogen receptor , gene. Estrogenicity in bile also was measured after deconjugation of steroids to provide an estimate of the exposure and as an endpoint for potential effects on the organism. In unexposed fish or fish exposed for three weeks at control localities, 0.5 to 9 ng of estradiol equivalents (EEq) were found per gram of bile (ng EEq/g bile). Fish exposed for three weeks in cages placed in the receiving waters near outlets of municipal effluent had an average activity of 26 ng EEq/g bile. Fish exposed to undiluted sewage water in aquaria had a bile estrogenicity of 51 to 87,000 ng EEq/g bile. Unconjugated estrogens contributed only 8% or less to the estrogenicity in bile of fish exposed to municipal effluents. Municipal sewage effluents were more estrogenic than the industrial effluents that were investigated. Estrogenicity in bile was compared to that in extracts of wastewater by using the same receptor assay, and to vitellogenin induction in the plasma of the same fish. Bile estrogenicity proved to be a useful and sensitive (internal) measure of exposure and indicated its potential for the display of biological effects as a complement or replacement of more laborious assays. [source]


Dietary accumulation of perfluorinated acids in juvenile rainbow trout (Oncorhynchus mykiss)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2003
Jonathan W. Martin
Abstract Perfluorinated acids (PFAs) recently have emerged as persistent global contaminants after their detection in wildlife and humans from various geographic locations. The highest concentrations of perfluorooctane sulfonate are characteristically observed in high trophic level organisms, indicating that PFAs may have a significant bioaccumulation potential. To examine this phenomenon quantitatively, we exposed juvenile rainbow trout (Oncorhynchus mykiss) simultaneously to a homologous series of perfluoroalkyl carboxylates and sulfonates for 34 d in the diet, followed by a 41-d depuration period. Carcass and liver concentrations were determined by using liquid chromatography-tandem mass spectrometry, and kinetic rates were calculated to determine compound-specific bioaccumulation parameters. Depuration rate constants ranged from 0.02 to 0.23/d, and decreased as the length of the fluorinated chain increased. Assimilation efficiency was greater than 50% for all test compounds, indicating efficient absorption from food. Bioaccumulation factors (BAFs) ranged from 0.038 to 1.0 and increased with length of the perfluorinated chain; however, BAFs were not statistically greater than 1 for any PFA. Sulfonates bioaccumulated to a greater extent than carboxylates of equivalent perfluoroalkyl chain length, indicating that hydrophobicity is not the sole determinant of PFA accumulation potential and that the acid function must be considered. Dietary exposure will not result in biomagnification of PFAs in juvenile trout, but extrapolation of these bioaccumulation parameters to larger fish and homeothermic organisms should not be performed. [source]


Dietary Na does not reduce dietary Cu uptake by juvenile rainbow trout

JOURNAL OF FISH BIOLOGY, Issue 2 2005
V. A. Kjoss
Rainbow trout Oncorhynchus mykiss fry in moderately hard water were exposed to control or high levels of dietary Cu (c. 6 and 580 ug Cu g food,1) at one of three levels of Na (1·5, 3·0 or 4·5%) in the diet, i.e. six experimental groups. Fish were fed a 4% body mass ration daily for 28 days and 10 individuals from each group were sampled every 7 days. Concentrations of Cu and Na were measured in the gills, liver, gut and remaining carcass of sampled fish. Growth was not affected and no consistent differences were found in mass, total lengths (LT) or indices of body condition among any of the groups on any sampling day. Copper concentration was significantly higher in tissues of Cu-exposed groups, although within treatment types (control Cu v. high Cu diet), it did not differ consistently among groups that received different levels of dietary Na. Tissue Na concentration did not differ among any of the groups and did not show any marked changes over time. In Cu-exposed groups, the proportion of total body Cu burden contained in the liver approximately doubled over time, from c. 30% on day 7 to c. 60% on day 28. In unexposed fish, the liver maintained c. 25% of the total Cu burden throughout the experiment. In contrast, the proportion of the total body Cu burden contained in the gut decreased somewhat over time in Cu-exposed fish, from c. 40% on day 7 to c. 30% on day 28, and remained fairly stable at c. 25,30% in control groups, i.e. approximately equal to liver values. In all groups, the carcass contained by far the largest portion of the total Na content (>80%). Measurements made 36 h post-feeding indicated that all six groups had much higher Na efflux relative to influx, suggesting that the fish were eliminating excess Na taken up from the diet, and differences in Na influx rates were small. Na efflux rate was significantly higher in the high Cu and high Na group than in the high Cu and low Na group. The results indicate that at the concentrations used in this experiment, dietary Na has little effect on dietary Cu uptake by juvenile rainbow trout, and dietary Cu has little effect on Na homeostasis. [source]


First description of non-motile Yersinia ruckeri serovar I strains causing disease in rainbow trout, Oncorhynchus mykiss (Walbaum), cultured in Spain

JOURNAL OF FISH DISEASES, Issue 6 2006
B Fouz
Abstract 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 × 102 to 6.3 × 103 cfu per fish) and bath challenge (5.1,7.3 × 106 cfu mL,1). This is the first description of Y. ruckeri serovar I biotype 2 causing disease in cultured trout in Spain vaccinated with commercial ERM vaccines. The occurrence of this emergent pathogen in Spanish continental aquaculture from its first isolation in 2001 to date is also documented. [source]


Characterization of serum and mucosal antibody responses and relative per cent survival in rainbow trout, Oncorhynchus mykiss (Walbaum), following immunization and challenge with Flavobacterium psychrophilum

JOURNAL OF FISH DISEASES, Issue 12 2002
B R LaFrentz
Abstract Serum and mucosal antibody responses of juvenile rainbow trout, Oncorhynchus mykiss, were characterized by enzyme-linked immunosorbent assay (ELISA) following immunization with various preparations of formalin-killed Flavobacterium psychrophilum cells. The protective nature of these preparations was then determined by immunizing rainbow trout fry and challenging with the bacterium. Juvenile rainbow trout immunized intraperitoneally (i.p.) with formalin-killed F. psychrophilum emulsified with Freund's complete adjuvant (FCA), and i.p. with formalin-killed F. psychrophilum either with or without culture supernatant generated significant serum antibody responses by 6 and 9 weeks, respectively. Significant mucosal antibody responses were detected by 9 weeks only in fish immunized i.p. with killed F. psychrophilum/FCA. Following immunization and bacterial challenge of rainbow trout fry, protective immunity was conferred in F. psychrophilum/FCA and saline/FCA groups with relative per cent survival values of up to 83 and 51, respectively. Significant protection was not observed in treatment groups immunized by immersion or i.p. without adjuvant at the challenge doses tested. Results suggest that stimulation of non-specific immune factors enhances the ability of fish to mount a protective immune response, but specific antibody appears necessary to provide near complete protection. In this study, an ELISA was developed to monitor anti- F. psychrophilum antibody production in trout. The relationship of such responses to protective immunity suggests that future vaccination strategies against coldwater disease may require stimulation of both the innate and adaptive arms of the immune response. [source]


Partial or total replacement of fishmeal by solvent-extracted cottonseed meal in diets for juvenile rainbow trout (Oncorhynchus mykiss)

AQUACULTURE NUTRITION, Issue 6 2006
L. LUO
Abstract The effect of solvent-extracted cottonseed meal (SCSM) as a partial or total replacement of fishmeal was studied in juvenile rainbow trout (Oncorhynchus mykiss). Six experimental diets SCSM0, SCSM25, SCSM50, SCSM75, SCSM75A and SCSMT, containing a gradient of SCSM 0, 152, 305, 465, 460 and 610 g kg,1 to replace 0, 112.5, 225, 337.5, 337.5 and 450 g kg,1 fishmeal protein were fed to triplicate groups (initial body weight of 39.2 ± 0.1 g) for 8 weeks. The diet SCSM75A was supplemented with lysine and methionine, to be similar to SCSM0 for juvenile rainbow trout. Faeces were colleted after 4 weeks of normal feeding for apparent digestibility coefficients (ADC) of dry matter, crude protein and gross energy determination. Total replacement of fishmeal adversely affected growth performance. Fish fed with diet SCSMT had significantly (P < 0.05) lower weight gain, specific growth ratio, feed conversion efficiency (FCE) and protein efficiency ratio than fish fed with other diets. The FCE of SCSM75 and SCSM75A were significantly lower (P < 0.05) than those of fish fed with SCSM0 diets. The ADC of the dry matter of SCSM75 and SCSMT were significantly lower than the SCSM0 diet, and the ADC of crude protein and the energy of SCSMT were the lowest (P < 0.05). The ADC of threonine, proline, alanine, valine, isoleucine, leucine, lysine and methionine of fish fed with diet SCSMT were lower. Lysine and methionine supplement positively affected the ADC of SCS75A diet. There were no significant differences in the fish body composition. It is shown that SCSM can be utilized in the juvenile rainbow trout diet up to 305 g kg,1, to replace about 50% of fishmeal protein in this experiment. [source]


Digestibility and growth performance of juvenile rainbow trout (Oncorhynchus mykiss) fed with pea and canola products

AQUACULTURE NUTRITION, Issue 2 2003
D.L. Thiessen
A digestibility experiment and subsequent 84-day feeding experiment evaluated the use of pea and canola meal products in diets for rainbow trout. The effect of milling and heat treatment on nutrient, dry matter and energy digestibility of raw/whole peas, raw/dehulled peas, extruded/dehulled peas and autoclaved air-classified pea protein was determined. Digestibility of the protein component was uniformly high for all pea ingredients (90.9,94.6%), regardless of the processing treatment. Autoclaving or extrusion increased starch digestibility by 41,75% (P , 0.05), which consequently increased energy and dry matter digestibility of whole and dehulled peas. Autoclaved air-classified pea protein had superior protein (94.6%), energy (87.0%) and dry matter (84.0%) digestibility (P , 0.05). It was demonstrated that inclusion of 25% dehulled peas, 20% air-classified pea protein or 20% canola meal fines was feasible in trout diets allowing for replacement of soya bean meal. The data showed no difference (P , 0.05) in feed intake, final weight and specific growth rate (SGR) measurements, and feed utilization was not compromised with inclusion of pea or canola meal products as the primary plant ingredient. It was concluded that dehulled peas, air-classified pea protein and canola meal fines are suitable ingredients for use in trout diet formulation at a level of 20%. [source]


Interaction between diet and genetic aptitude for weight and growth in juvenile rainbow trout, Oncorhynchus mykiss (Walbaum)

AQUACULTURE RESEARCH, Issue 8 2002
J M Blanc
Abstract Samples of rainbow trout, Oncorhynchus mykiss (Walbaum) alevins from 17 independent families (full-sib-groups) were raised from the start of feeding until the age of 18 weeks post-hatching with three diets (C, G and S) differing in protein content (fish soluble protein concentrate: 84% in C, 54% in G and 44% in S) and carbohydrates (none in C, 30% glucose in G and 40% crude corn starch in S). Fish were fed to near satiation, and their body weight and growth were measured. Diet effect was highly significant (G<,C < S), as well as the familial effect. The major part of the familial variance (80,90%) was common to the three diets. However, a minor part of the familial variance was observed to be diet dependent (family × diet interaction), and was found to result mainly from relative performances with carbohydrates (G and S diets) vs. pure protein (C diet). These results indicate that genetic improvement of growth should suffer little impairment from possible changes in future feed formulations. [source]