The division process of Cryptobia salmositica in experimentally infected rainbow trout (Salmo gairdneri)

1978 ◽  
Vol 56 (7) ◽  
pp. 1514-1518 ◽  
Author(s):  
Patrick T. K. Woo
Keyword(s):  
Rainbow Trout ◽  
Nuclear Division ◽  
Coho Salmon ◽  
The Body ◽  
Binary Fission ◽  
Salmo Gairdneri ◽  
Division Process

Cryptobia salmositica was isolated from its vector, Piscicola salmositica, which was collected from spawning salmon. The organisms were first injected into coho salmon and then maintained in rainbow trout. The process of multiplication is described from Giemsa's stained smears. The first stage of division is the production of two new flagella (one long and one short). This is followed by nuclear division which is not completed until kinetoplast division is completed. Body division commences from the posterior end soon after the long flagellum attaches to the body. Following this, the nucleus, the kinetoplast, and the blepharoplast migrate into the newly divided part of the organism. Final body division is completed after the migration of these organelles. Multiplication of C. salmositica is by unequal longitudinal binary fission.

Physiological Response of Juvenile Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri) to Handling and Crowding Stress in Intensive Fish Culture

1976 ◽  
Vol 33 (12) ◽  
pp. 2699-2702 ◽  
Author(s):  
Gary A. Wedemeyer
Keyword(s):  
Rainbow Trout ◽  
Feeding Behavior ◽  
Coho Salmon ◽  
Physiological Stress ◽  
Oncorhynchus Kisutch ◽  
Fish Distribution ◽  
Salmo Gairdneri ◽  
Crowding Stress ◽  
Normal Feeding ◽  
Intensive Fish Culture

Moving 4–5-in. coho salmon (Oncorhynchus kisutch) held in soft (20 ppm CaCO3) water from the relatively light loading density of 0.5 lb/ft3 to 1, 2, or 4 lb/ft3 (density index, DI = 0.1, 0.2, 0.4, 0.8) caused significant stress as indicated by loss of feeding behavior, but only minimal physiological disturbances, as indicated by lack of hyperglycemia or hypochloremia. However, moving them to 6 or 12 lb/ft3 (DI = 1.2, 2.4) caused significant physiological stress which required at least a week for recovery. Smolting coho salmon were physiologically stressed by population densities of 1 lb/ft3 or more and a subclinical corynebacterial kidney infection was activated. Rainbow trout (Salmo gairdneri) (4–5 in.) were physiologically stressed when moved and held at 1 lb/ft3 or more but retained normal feeding behavior. This indicates that handling and crowding stress will be minimized in softwater areas if densities in fish distribution trucks or in ponds or raceways during disease treatments are held to 0.1–0.5 lb/gal.

The effect of size on the fast-start performance of rainbow trout Salmo gairdneri, and a consideration of piscivorous predator-prey interactions

1976 ◽  
Vol 65 (1) ◽  
pp. 157-177 ◽  
Author(s):  
P. W. Webb
Keyword(s):  
Rainbow Trout ◽  
Reaction Time ◽  
Reaction Times ◽  
The Body ◽  
Salmo Gairdneri ◽  
Escape Behaviour ◽  
Predator Prey ◽  
Average Value ◽  
Fast Start ◽  
Prey Escape

The fast-start (acceleration) performance of seven groups of rainbow trout from 9-6 to 38-7 cm total length was measured in response to d.c. electric shock stimuli. Two fast-start kinematic patterns, L- and S-start were observed. In L-starts the body was bent into an L or U shape and a recoil turn normally accompanied acceleration. Free manoeuvre was not possible in L-starts without loss of speed. In S-starts the body was bent into an S-shape and fish accelerated without a recoil turn. The frequency of S-starts increased with size from 0 for the smallest fish to 60–65% for the largest fish. Acceleration turns were common. The radius of smallest turn for both fast-start patterns was proportional to length (L) with an overall radius of 0–17 L. The duration of the primary acceleration stages increased with size from 0–07 s for the group of smallest fish to 0–10 s for the group of largest fish. Acceleration rates were independent of size. The overall mean maximum rate was 3438 cm/s2 and the average value to the end of the primary acceleration movements was 1562 cm/s2. The distance covered and velocity attained after a given time for fish accelerating from rest were independent of size. The results are discussed in the context of interactions between a predator and prey fish following initial approach by the predator. It is concluded that the outcome of an interaction is likely to depend on reaction times of interacting fish responding to manoeuvres initiated by the predator or prey. The prey reaction time results in the performance of the predator exceeding that of the prey at any instant. The predator reaction time and predator error in responses to unpredictable prey manoeuvre are required for prey escape. It is predicted that a predator should strike the prey within 0-1 s if the fish are initially 5–15 cm apart as reported in the literature for predator-prey interactions. These distances would be increased for non-optimal prey escape behaviour and when the prey body was more compressed or depressed than the predator.

Viral Hemorrhagic Septicemia: Comparative Susceptibility of Rainbow Trout (Salmo gairdneri) and Hybrids (S. gairdneri × Oncorhynchus kisutch) to Experimental Infection

1976 ◽  
Vol 33 (5) ◽  
pp. 1205-1208 ◽  
Author(s):  
Wilma M. Ord ◽  
Monique Le Berre ◽  
Pierre de Kinkelin
Keyword(s):  
Rainbow Trout ◽  
Experimental Infection ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Viral Hemorrhagic Septicemia ◽  
Comparative Susceptibility

Rainbow trout (Salmo gairdneri) fry and yearlings were compared with hybrids of rainbow trout and coho salmon (Oncorhynchus kisutch) for susceptibility to viral hemorrhagic septicemia (VHS). In three trials, exposure to waterborne infectivity consistently resulted in a 77% mortality of rainbow trout fry while loss among the hybrid fry averaged only 11%. Tests showed survivors might be carriers of virus. Hybrid yearlings infected by gill brushing were fully refractory to VHS whereas mortality (3:8) and viremia were recorded among gill-infected rainbow trout yearlings.

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

Observations on the life-cycle of the strigeoid trematode, Apatemon (Apatemon) gracilis (Rudolphi, 1819) Szidat, 1928

1976 ◽  
Vol 50 (2) ◽  
pp. 125-132 ◽  
Author(s):  
David Blair
Keyword(s):  
Life Cycle ◽  
Rainbow Trout ◽  
Salmo Trutta ◽  
Fish Host ◽  
The Body ◽  
Salmo Gairdneri ◽  
Stone Loach ◽  
Experimental Conditions ◽  
Pericardial Cavity ◽  
Wide Range

AbstractThe life-cycle of Apatemon (A.) gracilis was completed in the laboratory. The snail host is Lymnaeaperegra (Müller). The cercaria is redescribed from a wide range of material. Metacercariae were found in naturally infected rainbow trout (Salmo gairdneri Richardson), three-spined sticklebacks (Gasterosteus aculeatiis L.) and stone loach (Nemacheilus barbatulus (L.)) from Scotland and in three-spined sticklebacks from Iceland. In trout, most metacercariae were found in the pericardial cavity, in sticklebacks, the eye, and in loach, the body cavity. In infection experiments, cercariae from naturally infected Scottish snails developed in threespined sticklebacks, rainbow trout and brown trout (Salmo trutta L.). Under experimental conditions cercariae did not penetrate stone loach, although this species is naturally infected with A gracilis. The phenomenon of fish host specificity is briefly discussed. Development of the metacercaria is described. Excystation of metacercarial cysts with pepsin and trypsin solutions is unlike that reported for any other digenean; the contents of the cyst appear to be under pressure. In pepsin, layers of the cyst wall peel back from one end. When transferred to trypsin, one pole of the cyst ruptures and the worm is forcibly expelled.

Contaminant Accumulation and Physiological Response in Rainbow Trout (Salmo gairdneri) Reared on Naturally Contaminated Diets

1983 ◽  
Vol 40 (11) ◽  
pp. 1987-1994 ◽  
Author(s):  
J. W. Hilton ◽  
P. V. Hodson ◽  
H. E. Braun ◽  
J. L. Leatherland ◽  
S. J. Slinger
Keyword(s):  
Rainbow Trout ◽  
Pacific Ocean ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Body Burden ◽  
Lake Ontario ◽  
Abnormal Behavior ◽  
Salmo Gairdneri ◽  
Human Consumption ◽  
Thyroid Hyperplasia

Juvenile rainbow trout were reared for 24 wk on practical-type diets formulated with fish meals derived from coho salmon (Oncorhynchus kisutch) taken from Lake Michigan, Lake Ontario, and the Pacific Ocean. Levels of contaminants (DDT, chlordane, dieldrin, mirex, and PCBs) increased 10-fold from control and Pacific Ocean salmon-based diets to Lake Ontario salmon-based diets. Rainbow trout accumulated contaminants in direct proportion to dietary levels. However, there were no significant differences in the final body weights, feed to gain ratios, or mortality rates of the trout reared on the different test diets. No signs of abnormal behavior or any indication of histopathological abnormalities were observed in any of the fish. There were no signs of thyroid hyperplasia or any significant decline in serum T3 or T4 levels with increasing dietary contaminant levels. Therefore, rainbow trout do not appear to have been affected by the uptake and accumulation of contaminants. However, the trout did not appear to regulate their body burden of contaminants; this ultimately could prove to be toxic and may adversely affect the ability of these fish to reproduce and survive. The final concentrations of mirex and PCBs in the Lake Ontario-fed fish exceeded the allowed limits to protect human health; therefore, fish meals produced from Lake Ontario salmon are unsuitable as a source of feed for aquaculture of rainbow trout intended for human consumption.

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