A Standardized Model of Experimental Furunculosis in Rainbow Trout (Salmo gairdneri)

1980 ◽  
Vol 37 (4) ◽  
pp. 746-750 ◽  
Author(s):  
C. Michel
Keyword(s):  
Rainbow Trout ◽  
Intramuscular Injection ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Exponential Growth Phase ◽  
Cell Counts ◽  
Viable Cells ◽  
Treated Fish ◽  
Drop Plate

With the aid of published information, we have developed a standardized and reproducible experimental model of furunculosis in rainbow trout (Salmo gairdneri). The infective doses (LD50 = 200 to 2000 germs, i.m.) employed strains of Aeromonas salmonicida, the virulence of which was maintained by passage in 15-g fingerlings. The number of viable cells in the dose was conveniently determined using the drop-plate enumeration technique; however, meaningful cell counts could only be obtained if broth cultures used for infecting the fish were harvested early in the exponential growth phase (OD < 1.000 at 525 nm). Better results were obtained with intramuscular injection than with intraperitoneal injection. The infection procedure involved injecting a dose of 10 LD50, intramuscularly, into each of 30 fish held at 15 °C and recording the mortalities for 10 d. Protection tests in which Tribrissen (28 mg sulfadiazine and 5.6 mg trimethoprim/kg fish for 8 d) was fed or tetracycline (1 mg per fish) i.m. injected into the infected fish served to demonstrate the value of the model. Results were in agreement with field observations with no death for treated fish and a mortality of 96%, for untreated fish. Key wordss rainbow trout, Salmo gairdneri; Aeromonas salmonicida, furunculosis, experimental infection

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Lake Trout ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Dolly Varden Salvelinus Malma ◽  
Prosopium Williamsoni

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

Aeromonas salmonicida: Relationship between Extracellular Growth Products and Isolate Virulence

1981 ◽  
Vol 38 (11) ◽  
pp. 1322-1326 ◽  
Author(s):  
Rocco C. Cipriano ◽  
Billy R. Griffin ◽  
Burton C. Lidgerding
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Lesion Development ◽  
Culture Supernatants ◽  
Crude Material

Extracellular growth products, extracted from culture supernatants of Aeromonas salmonicida by precipitation with ammonium sulfate and ethanol, were resolved into four fractions by ion-exchange chromatography. Although one of these (fraction II) possessed leukocytolytic activity, virulence of the pathogen was not associated with leukocytotoxicity. A positive correlation was established, however, between virulence and the toxicity of extracted material to cultured rainbow trout gonad (RTG-2) cells. The crude material and fractions II and III from virulent isolates were more toxic to RTG-2 cells than were similar preparations from avirulent isolates. Preparations from virulent isolates caused hemorrhaging, lesion development, and mortality when injected intramuscularly into brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo solar). Rainbow trout (Salmo gairdneri) were more resistant and lesions could be produced only with fraction II. Fraction II also possessed proteolytic activity.Key words: Aeromonas salmonicida, furunculosis, pathogenicity, salmonids, extracellular products, cytotoxicity, leukocytolysis, proteolysis, fishes

Susceptibility of Trouts of Different Species and Origins to Various Isolates of Infectious Pancreatic Necrosis Virus

1982 ◽  
Vol 39 (12) ◽  
pp. 1580-1584 ◽  
Author(s):  
A. Silim ◽  
M. A. S. Y. Elazhary ◽  
A. Lagacé
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Pancreatic Necrosis ◽  
Lake Trout ◽  
Infectious Pancreatic Necrosis Virus ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Necrosis Virus ◽  
Infectious Pancreatic Necrosis ◽  
Pancreatic Necrosis Virus

We investigated the susceptibility of trouts of different species and origins to infectious pancreatic necrosis virus (IPNV) and the pathogenicity of three strains of IPNV for brook trout (Salvelinus fontinalis) of various origins and lake trout (Salvelinus namaycush) of a single origin. Fish were inoculated by immersion in water containing 105 PFU of virus/mL for 6 h. Susceptibility to IPNV infection was assessed by counting dead fish over a period of 21 d after infection and on histological lesions in the pancreas, kidney, and intestine of the infected fish. Different species of trouts had different susceptibility to IPNV strain 3865. Brook trout had the highest mortality followed by rainbow trout (Salmo gairdneri), whereas the least mortality occurred in lake trout. Brook trout from Crowford, Nebraska, were more than twice as susceptible as the same species from Baldwin Mills, Quebec. Rainbow trout also varied in susceptibility as a result of origin. Virus isolate 3B, originally isolated from chain pickerel (Esox niger), was less virulent than isolates 4495 or 3865 (both from trout). Hatcheries that use water from sources containing pickerel may increase their chances of IPN infection.Key words: trout species, infectious pancreatic necrosis virus, resistance

A Leukocytolytic Factor Isolated from Cultures of Aeromonas salmonicida

1977 ◽  
Vol 34 (8) ◽  
pp. 1118-1125 ◽  
Author(s):  
D. W. Fuller ◽  
K. S. Pilcher ◽  
J. L. Fryer
Keyword(s):  
Rainbow Trout ◽  
Virulence Factors ◽  
Coho Salmon ◽  
Virulent Strain ◽  
Deae Cellulose ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Amino Sugars ◽  
Avirulent Strain

A substance characterized as a glycoprotein, isolated from the supernatant fluids of broth cultures of Aeromonas salmonicida by a combination of ammonium sulfate and ethanol precipitations followed by chromatography on DEAE-cellulose, was cytolytic for rainbow trout (Salmo gairdneri) leukocytes, and antigenic when injected into rabbits. The ratio of protein to hexose determined by analysis of the purified fraction was between 0.35 and 0.45, and small amounts of amino sugars were detected. A virulent strain of A. salmonicida produced much more of this factor than an avirulent strain. This factor was cytolytic for leukocytes in vitro and also produced a pronounced leukopenia when injected intravenously in adult rainbow trout. When injected in small coho salmon (Oncorhyncus kisutch) 8–13 cm long together with about one LD50 of live A. salmonicida 36 of 40 fish succumbed to the combination, whereas only 14 of 40 died from an injection of the bacterium alone. Thus, the pathogenicity of the organism was enhanced, presumably by increasing the susceptibility of the host. Hence, this glycoprotein apparently is one of the virulence factors of this bacterium. Key words: leukocytolytic factor, Aeromonas salmonicida, glycoprotein, virulence factor

Ecophysiology and Mercury Accumulation of Rainbow Trout (Salmo gairdneri) When Exposed to Mercury in Various Concentrations of Chloride

1986 ◽  
Vol 43 (3) ◽  
pp. 710-714 ◽  
Author(s):  
Barbara Z. Walczak ◽  
U. Theodore Hammer ◽  
P. Ming Huang
Keyword(s):  
Rainbow Trout ◽  
Chloride Concentration ◽  
Plasma Potassium ◽  
Salmo Gairdneri ◽  
Plasma Sodium ◽  
Mercury Accumulation ◽  
Cell Counts ◽  
Plasma Sodium Level ◽  
White Blood Cell Counts ◽  
Chloride Concentrations

Rainbow trout (Salmo gairdneri) mortality was 100% when exposed to HgCl2 (2–10 μg∙Hg2+∙L−1) for 14 d in a natural low chloride medium. There was no mortality if the medium contained 100, 200, or 400 mg Cl−∙L−1 or more. Accumulation of mercury was highest in kidneys (0.65–13 μg∙g−1), spleen (0.31–4.2), gills (0.46–4.15), and liver (0.53–2.1) but accumulations differed for periods of exposure (14 or 42 d) and chloride concentration in the medium (100 or 200 mg Cl−∙L−1). In rainbow trout exposed to HgCl2 for 42 d, there were significant increases in plasma sodium level at 200 mg Cl−∙L−1 and significant decreases in plasma potassium, albumin, α1-globulin, and β-globulin levels in 100 mg Cl−∙L−1. No significant changes occurred in these parameters at other chloride concentrations or in erythrocytes, hematocrit, mean corpuscular volume, white blood cell counts, or chloride plasma levels. Although chloride concentrations in the media affect mercury accumulation by different organs as well as affecting physiological functions, there appears to be no direct relationship except for reduced mortality.

Visual pigment changes in the rainbow trout, Salmo gairdneri

1972 ◽  
Vol 50 (8) ◽  
pp. 1117-1126 ◽  
Author(s):  
W. L. Jacquest ◽  
D. D. Beatty
Keyword(s):  
Rainbow Trout ◽  
Visual Pigment ◽  
Intramuscular Injection ◽  
Visual Pigments ◽  
The Other ◽  
Salmo Gairdneri ◽  
Thyrotropic Hormone

The retinae of rainbow trout, Salmo gairdneri, have mixtures of two visual pigments, one based on retinaldehyde (VP5031), the other on 3-dehydroretinaldehyde (VP5272). Increases in the proportion of VP5272 or maintained high percentages of VP5272 were induced in three ways: (1) feeding a diet rich in 3-dehydroretinol; (2) intraperitoneal injections of L-thyroxine; and (3) intramuscular injection of bovine thyrotropic hormone. The possible significance of these findings in relation to carotenoid conversions in fish is discussed.

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