Effects of Diet, Ambient Temperature, and Holding Conditions on Plasma Thyroxine Levels in Rainbow Trout (Salmo gairdneri)

1977 ◽  
Vol 34 (5) ◽  
pp. 677-682 ◽  
Author(s):  
J. F. Leatherland ◽  
C. Y. Cho ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Epithelial Cell ◽  
Soybean Oil ◽  
Salmo Gairdneri ◽  
Light Phase ◽  
Cell Height ◽  
Significant Difference ◽  
Pelleted Diet ◽  
Soybean Diet ◽  
Significant Diurnal Variation

Rainbow trout (Salmo gairdneri) acclimated to 19 °C and fed a pelleted diet of either 6% soybean oil or 6% tallow fat had similar plasma thyroxine levels (0.62 ± 0.10 and 0.69 ± 0.08 μg/100 ml, respectively), although fish acclimated to 7 °C and fed the soybean diet gave significantly (P < 0.05) higher plasma thyroxine concentration (1.32 ± 0.13 μg/100 ml) than the group fed the tallow fat diet (0.95 ± 0.12 μg/100 ml). The plasma thyroxine concentration in the fish fed the soybean oil diet was significantly (P < 0.01) higher at 7 °C than at 19 °C. There was no significant difference between the two groups of fish given the tallow fat diet. Epithelial cell heights were largest in groups with the highest plasma thyroxine levels. Epithelial cell height in the two groups at 19 °C were similar, but in both groups of fish at 7 °C, the cell height was significantly greater than in either of the groups at 19 °C (P < 0.01 for comparisons of the 19 °C tallow fat diet with both groups of 7 °C acclimated fish and comparison of the two groups on the soybean oil diet; P < 0.05 for comparisons of the 19 °C, soybean oil diet with the group held at 7 °C and given the tallow fat diet). Fish deprived of food for 40 days had a significantly (P < 0.05) lower plasma thyroxine concentration when compared with fish that had been fed daily. There was no significant diurnal variation in plasma thyroxine over the light phase of a 12 h light: 12 h dark photoperiod, nor did the limitation of light entering the aquaria significantly affect plasma thyroxine values. Key words: endocrine, thyroid, Salmo gairdneri, diet, environmental temperature

Temperature Selection of Rainbow Trout (Salmo gairdneri) Fingerlings in Vertical and Horizontal Gradients

1971 ◽  
Vol 28 (11) ◽  
pp. 1801-1804 ◽  
Author(s):  
R. W. McCauley ◽  
W. L. Pond
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Temperature Preference ◽  
Temperature Selection ◽  
Horizontal Gradients ◽  
Significant Difference ◽  
Preferred Temperatures ◽  
Laboratory Investigations ◽  
Horizontal Temperature Gradients ◽  
Selection Of

Preferred temperatures of underyearling rainbow trout (Salmo gairdneri) were determined in both vertical and horizontal temperature gradients. No statistically significant difference was found between the preferred temperatures by the two different methods. This suggests that the nature of the gradient plays a lesser role than generally believed in laboratory investigations of temperature preference.

Sublethal Effects of Environmental Acidification on Rainbow Trout (Salmo gairdneri)

1979 ◽  
Vol 36 (1) ◽  
pp. 84-87 ◽  
Author(s):  
C. M. Neville
Keyword(s):  
Rainbow Trout ◽  
Species Differences ◽  
Sublethal Effects ◽  
Anaerobic Respiration ◽  
Acid Group ◽  
Salmo Gairdneri ◽  
Significant Difference ◽  
Caudal Vein ◽  
Erythrocyte Concentration ◽  
Oxygen Carrying Capacity

Dorsal aorta blood samples were taken from cannulated rainbow trout (Salmo gairdneri) exposed to pH 4.0 (acid group) or pH 7.0 (controls) in normocapnic conditions at 10 °C. Over a 5-d period there was a significant gradual decrease in pH and total CO2 in the acid group but no significant difference in pO2 and lactate compared to the controls. After uncannulated rainbow trout were exposed to the same conditions for 12 d there were significant increases in hemoglobin, hematocrit, and erythrocyte levels in caudal vein samples from the acid group. The results show that rainbow trout exposed to acid without hypercapnia develop acidaemia which is not a result of anaerobic respiration. The increase in erythrocyte concentration probably offsets the effects of acidaemia upon blood oxygen carrying capacity. Differences in ambient pCO2 and/or species differences could account for varying acid-base values in acid exposed fish reported by different workers. Key words: environmental acidification, acidaemia, lactate, pH, total carbonate, fish

Oral Immunization of Rainbow Trout (Salmo gairdneri) Against an Etiologic Agent of "Redmouth Disease"

1965 ◽  
Vol 22 (3) ◽  
pp. 713-719 ◽  
Author(s):  
A. J. Ross ◽  
G. W. Klontz
Keyword(s):  
Rainbow Trout ◽  
Oral Immunization ◽  
Etiologic Agent ◽  
Salmo Gairdneri ◽  
Bacterial Disease ◽  
Pelleted Diet

Rainbow trout were fed a pelleted diet containing killed cells of the etiologic agent of a bacterial disease, redmouth. These fish in addition to appropriate controls were subsequently challenged with virulent homologous organisms. Ninety per cent of the redmouth immunized fish survived the basic challenge using virulent organisms in contrast to 20% survival for the controls. Multiple challenge doses at increased levels also are discussed.

Swimming Performance and Behavior of Rainbow Trout (Salmo gairdneri) and White Perch (Morone americana): Effects of Attaching Telemetry Transmitters

1985 ◽  
Vol 42 (3) ◽  
pp. 488-493 ◽  
Author(s):  
Ernest J. Mellas ◽  
James M. Haynes
Keyword(s):  
Rainbow Trout ◽  
White Perch ◽  
Fungal Infections ◽  
Swimming Performance ◽  
Dominance Rank ◽  
Salmo Gairdneri ◽  
Morone Americana ◽  
Significant Difference ◽  
Dominant Fish ◽  
And Behavior

Implicit in biotelemetry studies is the assumption that transmitter attachment does not affect fish behavior or performance. We conducted experiments to determine effects of external, surgical, and stomach tag attachments on the swimming performance and behavior of rainbow trout (Salmo gairdneri) and white perch (Morone americana). Only one rainbow trout changed dominance rank after dummy tag attachment. Subordinate fish had significantly lower weights than subdominant and dominant fish, but there were no significant differences in exhaustion times. Externally tagged trout had significantly lower exhaustion times than other tagged groups and controls. There was no significant difference in exhaustion times among tagged white perch and controls. Externally and surgically tagged perch contracted serious fungal infections during a 45-d survival study; however, few disease and no survival problems among tagged and untagged rainbow trout were noted up to 21 d. With all factors taken into account, it appears that stomach tagging is the best method of transmitter attachment, except when regurgitation and/or stomach atrophy are likely to be encountered.

scholarly journals Effect of selenium deficiency on hydroperoxide-stimulated release of glutathione from isolated perfused liver of rainbow trout (Salmo gairdneri)

1986 ◽  
Vol 56 (2) ◽  
pp. 421-428 ◽  
Author(s):  
J. G. Bell ◽  
J. W. Adron ◽  
C. B. Cowey
Keyword(s):  
Hydrogen Peroxide ◽  
Rainbow Trout ◽  
Weight Gain ◽  
Peroxidase Activity ◽  
Selenium Deficiency ◽  
Salmo Gairdneri ◽  
Perfused Liver ◽  
Deficient Diet ◽  
Significant Difference ◽  
Glutathione Disulphide

1. Duplicate groups of rainbow trout (Salmo gairdneri) were each given partially purified diets which were either adequate or depleted in selenium for 40 weeks.2. Although there was no significant difference in weight gain, liver Se concentration was significantly lower in fish given the deficient diet.3. Glutathione (GSH) peroxidase (EC 1. 11. 1. 9) activity was significantly reduced in liver of Se-deficient fish but a differential assay did not indicate the presence of a non-Se-dependent GSH peroxidase activity, although liver GSH S-transferase (EC 2. 5. 1. 18) was significantly increased.4. Perfusion of livers from trout given Se-adequate diets with t-butyl hydroperoxide (BuOOH) or hydrogen peroxide caused an increase in the rate of release of glutathione disulphide (GSSG) into the perfusate.5. Perfusion of livers from Se-deficient trout with BuOOH or H2O2 did not result in any change in rate of release of GSSG into the perfusate.6. These findings confirm the absence of any compensatory non-Se-dependent peroxidase activity in Se-depleted trout.

Olfactory Bulbar Electrical Responses of Rainbow Trout (Salmo gairdneri) Exposed to Morpholine During Smoltification

1979 ◽  
Vol 36 (10) ◽  
pp. 1186-1190 ◽  
Author(s):  
Toshiaki J. Hara ◽  
S. B. Brown
Keyword(s):  
Rainbow Trout ◽  
Key Words ◽  
Electrical Response ◽  
Salmo Gairdneri ◽  
Induced Responses ◽  
Salmonid Fishes ◽  
Key Words Olfaction ◽  
Sulfhydryl Reagent ◽  
Significant Difference ◽  
Olfactory Organs

Exposure of rainbow trout (Salmo gairdneri) to 5.7 × 10−10 M (5 × 10−5 mg/L) morpholine during smoking period did not influence the subsequent neural response to this substance, when tested immediately and 12 mo after smoking. No significant difference in the morpholine-induced responses was obtained between the exposed and unexposed fish. Using N-ethylmaleimide, a sulfhydryl reagent, it was further confirmed that the morpholine-effect is caused by a mechanism not directly associated with the normal olfactory function. Perfusion of the olfactory organs with 1.0 × 10−1 and 1.1 × 10−1 M (1%) morpholine for 10 min irreversibly inhibited the olfactory responsiveness to odorants. Sensitization of the olfactory bulbar electrical response is discussed in connection with homing of morpholine-imprinted salmonid fishes. Key words: olfaction, olfactory bulbar response, rainbow trout, salmon, imprinting, morpholine, homing, migration

Pleiotropic effects of a regulatory gene (Pgm-1-t) on the social behavior of juvenile rainbow trout (Salmo gairdneri)

1985 ◽  
Vol 63 (12) ◽  
pp. 2847-2851 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann
Keyword(s):  
Rainbow Trout ◽  
Social Behavior ◽  
Regulatory Gene ◽  
Developmental Rate ◽  
Pleiotropic Effects ◽  
Salmo Gairdneri ◽  
Juvenile Rainbow Trout ◽  
The Social ◽  
Significant Difference ◽  
Primary Determinant

We compared the social behavior of juvenile rainbow trout with a regulatory allele, Pgm-1-t(b), to their full-sibs without this allele. Other studies have shown that this gene has many pleiotropic effects in the Arlee strain, the most obvious being an increase in developmental rate at about the time of hatching. The frequencies of two agonistic action patterns, charge and lateral display, and two nonagonistic measures, yawn and forage, were used to describe early social behavior. Pgm-1-t(b) was associated with significantly higher frequencies of charge and larger size in fish from the Arlee strain. However, fish from the DeSmet strain with Pgm-1-t(b) were no more aggressive or longer than their full-sibs lacking this allele. Length was the primary determinant of dominance status in both strains, regardless of Pgm-1-t genotype. In both strains, there was no significant difference between genotypes in the frequency of lateral display and forage. Our results show that genetic differences at a single locus can have pleiotropic effects on behavior with potential adaptive significance.

Plaque-Forming Cells and Humoral Antibody in Rainbow Trout (Salmo gairdneri) Induced by Immersion in a Yersinia ruckeri O-Antigen Preparation

1979 ◽  
Vol 36 (6) ◽  
pp. 636-639 ◽  
Author(s):  
D. P. Anderson ◽  
B. S. Roberson ◽  
O. W. Dixon
Keyword(s):  
Rainbow Trout ◽  
Plaque Assay ◽  
Control Fish ◽  
Salmo Gairdneri ◽  
Yersinia Ruckeri ◽  
Passive Hemagglutination ◽  
Humoral Antibody ◽  
O Antigen ◽  
Significant Difference ◽  
Antibody Titers

Rainbow trout (Salmo gairdneri) were exposed to the O-antigen of Yersinia ruckeri by various immunization regimens. The passive hemolytic plaque assay was used to show specific splenic plaque-forming cells (PFC) and passive hemagglutination demonstrated humoral antibody titers in fish injected with or immersed in the antigen preparations. Preceding antigen immersion with a 2-min immersion in either a 5.2 or a 2.6% NaCl solution did not affect the numbers of PFC or levels of antibody. Fish held for 2 min in ethyl m-aminobenzoate methanesulfonate (MS-222®) before antigen immersion showed no significant difference from the control fish. Dosage studies showed that the minimal concentration of antigen for induction of PFC by immersion was 5.0 μg/mL. Key words: plaque-forming cells, immunization, rainbow trout immersion, Yersinia ruckeri

Fixation Artifacts in Rainbow Trout (Salmo gairdneri) Gills: A Morphometric Evaluation

1989 ◽  
Vol 46 (5) ◽  
pp. 780-785 ◽  
Author(s):  
D. J. Speare ◽  
H. W. Ferguson
Keyword(s):  
Rainbow Trout ◽  
Epithelial Cell ◽  
Chloride Cells ◽  
Salmo Gairdneri ◽  
Histopathological Changes ◽  
Whole Mount ◽  
Gill Lamellae ◽  
Linear Manner ◽  
Morphometric Evaluation ◽  
Fixation Delay

Epithelial capillary separation (E.C.S.) and epithelial cell hypertrophy (E.H.) of the gill lamellae of fish are two histopathological changes frequently described in association with toxic insults. Both of these gill changes increased in a significant linear manner over delay periods of 20–900 s from death to first entering either Bouin's or 10% formalin fixative. E.C.S. also occurred rapidly when gills were examined as whole mount preparations. The presence of occasional necrotic epithelial and chloride cells resembled apoptosis and is not in itself abnormal, nor did the type of fixative used or fixation delay have an effect on their extent. Gills from fish killed by either MS-222 or cervical spinal severance were similar, except that the latter also had multifocal lamellar telangiectasis. We conclude that E.C.S. and E.H. are readily mimicked by preparation and postmortem artifacts that occur rapidly after death when this is caused by either MS-222 or spinal severance. Bouin's fixative should be used to minimize these changes.

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