Experimental Infection of Rainbow Trout, Oncorhynchus mykiss, with Contracaecum osculatum (Rudolphi, 1802) and Pseudoterranova decipiens (Krabbe, 1878) (Nematoda; Ascaridoidea)

1990 ◽  
Vol 47 (12) ◽  
pp. 2293-2296 ◽  
Author(s):  
J. W. Smith ◽  
A. E. Elarifi ◽  
R. Wootten ◽  
A. W. Pike ◽  
M. D. B. Burt
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Body Cavity ◽  
The Body ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pseudoterranova Decipiens ◽  
Third Stage ◽  
Contracaecum Osculatum ◽  
Merlangius Merlangus ◽  
Northern North Sea

The fate of freshly hatched larvae of the marine ascaridoid nematodes Contracaecum osculatum and Pseudoterranova decipiens (from grey seals, Halichoerus grypus, from Scotland and the Canadian Atlantic) was investigated following oral or intraperitoneal introduction into rainbow trout, Oncorhynchus mykiss, maintained at 7–13 °C in fresh water. Neither species appeared to survive for long in the trout alimentary tract following oral introduction; a few larvae were found alive after 2 d but none after 21 d. intraperitoneally, P. decipiens did not survive beyond 21 d, but some C. osculatum exsheathed and developed over several months to lengths over 13 mm, and morphologically and morphometrically resembled third-stage larvae from naturally infected whiting, Merlangius merlangus, from the northern North Sea; no moult was detected. Thus, freshly hatched free-living larvae of C. osculatum are able to develop directly to the third stage in the body cavity of a fish without earlier passage through a crustacean or other invertebrate host.

scholarly journals Post-ovulatory secretion of pituitary gonadotropins GtH I and GtH II in the rainbow trout (Oncorhynchus mykiss): regulation by steroids and possible role of non-steroidal gonadal factors

1999 ◽  
Vol 163 (1) ◽  
pp. 87-97 ◽  
Author(s):  
J Chyb ◽  
T Mikolajczyk ◽  
B Breton
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Body Cavity ◽  
The Body ◽  
Ovarian Fluid ◽  
Multiple Injections ◽  
Rainbow Trout Oncorhynchus Mykiss

In order to determine the factors of ovarian origin which can modulate the postovulatory secretion of the FSH-like gonadotropin (GtH I) and the LH-like gonadotropin (GtH II), freshly ovulated female rainbow trout were divided into two groups. In the first group the fish were stripped in order to eliminate the eggs and ovarian fluid from the body cavity, while in the second group the eggs were kept in the body cavity. Subsequently, fish from both groups were implanted with testosterone (10 mg/kg), 17beta-estradiol (10 mg/kg) or 17,20beta-ddihydroxy-4-regnen-3-one (17,20betaP) (1 mg/kg) or injected every 2 days with desteroidized ovarian fluid (1.5 ml/kg). The secretion of GtH I dramatically increased in stripped fish, reaching its maximum levels 2 weeks after ovulation. The preservation of eggs in the body cavity led to the suppression of this increase. The profiles of GtH II secretion were opposite to those encountered for GtH I because the increase of GtH II was observed only in unstripped fish. The administration of steroids showed that testosterone is able to inhibit GtH I release and stimulate that of GtH II in stripped fish, having no effect on the release of these gonadotropins in non-stripped animals. 17beta-Estradiol failed to modify GtH I secretion, however it decreased the release of GtH II in fish containing retained eggs in the body cavity. 17,20betaP had a delayed stimulating influence on GtH I release in unstripped fish. Finally, multiple injections of desteroidized ovarian fluid into stripped fish led to a significant decrease of GtH I release and to an increase of GtH II secretion. This study demonstrates that factors, which are present in ovarian fluid, modulate the post-ovulatory secretion of both gonadotropins--their net action is negative on GtH I and positive on GtH II. Among the steroids, testosterone is of major importance, being able to inhibit GtH I release and to stimulate that of GtH II. We also show that non-steroidal factors present in the ovarian fluid can influence the release of both gonadotropins, which indirectly supports the previous findings about the existence of inhibin/activin-like factors in fish.

Myotomal slow muscle function of rainbow trout Oncorhynchus mykiss during steady swimming.

1998 ◽  
Vol 201 (10) ◽  
pp. 1659-1671 ◽  
Author(s):  
L Hammond ◽  
J D Altringham ◽  
C S Wardle
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Body Length ◽  
Muscle Activation ◽  
Activity Patterns ◽  
The Body ◽  
Entire Body ◽  
Negative Power ◽  
Rainbow Trout Oncorhynchus Mykiss

Strain and activity patterns were determined during slow steady swimming (tailbeat frequency 1.5-2.5 Hz) at three locations on the body in the slow myotomal muscle of rainbow trout Oncorhynchus mykiss using sonomicrometry and electromyography. Strain was independent of tailbeat frequency over the range studied and increased significantly from +/-3.3 % l0 at 0.35BL to +/-6 % at 0.65BL, where l0 is muscle resting length and BL is total body length. Muscle activation occurred significantly later in the strain cycle at 0.35BL (phase shift 59 degrees) than at 0.65BL (30 degrees), and the duration of activity was significantly longer (211 degrees at 0.35BL and 181 degrees at 0.65BL). These results differ from those of previous studies. The results have been used to simulate in vivo activity in isolated muscle preparations using the work loop technique. Preparations from all three locations generated net positive power under in vivo conditions, but the negative power component increased from head to tail. Both kinematically, and in the way its muscle functions to generate hydrodynamic thrust, the rainbow trout appears to be intermediate between anguilliform swimmers such as the eel, which generate thrust along their entire body length, and carangiform fish (e.g. saithe Pollachius virens), which generate thrust primarily at the tail blade.

Cell-mediated Immune Response of Rainbow Trout (Oncorhynchus mykiss) to Larval Pseudoterranova decipiens (Nematoda; Ascaridoidea) following Sensitization to Live Sealworm, Sealworm Extract, and Nonhomologous Extracts

1993 ◽  
Vol 50 (1) ◽  
pp. 60-65 ◽  
Author(s):  
N. R. Ramakrishna ◽  
M. D. B. Burt ◽  
B. M. MacKinnon
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Cell Function ◽  
Secondary Response ◽  
Control Fish ◽  
Cell Mediated Immunity ◽  
Specific Response ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pseudoterranova Decipiens ◽  
Test Fish

The delaved-type hypersensitivity (DTH) reaction (an in vivo manifestation of cell-mediated immunity) was studied in rainbow trout (Oncorhynchus mykiss) exposed to sealworm Pseudoterranova decipiens infections. Test fish immunized with sealworm extract and live intact worms, were compared with control fish which received either phosphate-buffered saline (negative control) or nonhomologous cestode or nematode antigens (positive control). Test fish immunized with sealworm extract produced a typical DTH reaction to live sealworm, challenge. The DTH reaction was similar to that in mammals and showed lymphoid and mononuclear cell infiltration. The electron microscopical studies revealed the presence of activated macrophages and plasma cells in the reaction zone. The specific response, following immunization with homologous antigens, supports the existence of T-cell function with anamnesis in rainbow trout exposed to sealworm antigens. However, when the test fish were immunized with live sealworms and later challenged with live sealworms, the secondary response was poor and showed no difference from controls and naive fish.

scholarly journals Telomere length variation does not correspond with the growth disturbances in the rainbow trout (Oncorhynchus mykiss)

2021 ◽  
Author(s):  
Ligia Panasiak ◽  
Karolina Szubert ◽  
Marcin Polonis ◽  
Konrad Ocalewicz
Keyword(s):  
Rainbow Trout ◽  
Body Size ◽  
Oncorhynchus Mykiss ◽  
Telomere Length ◽  
Somatic Growth ◽  
Normal Growth ◽  
The Body ◽  
Length Variation ◽  
Telomere Attrition ◽  
Rainbow Trout Oncorhynchus Mykiss

AbstractSomatic growth is considered to affect pace of the telomere attrition in vertebrates. As normally developed and dwarf fish differ in the body size we have decided to compare telomere length in the rainbow trout (Oncorhynchus mykiss) with normal growth and with growth reduced due to the dwarf condition. Examined 1-year-old fish with normal and dwarf appearance were siblings originated from androgenetic fully homozygous doubled haploid (DH) line of rainbow trout. Particular dwarf individuals had body deformities such as humpback, kyphosis, and lordosis. Somatic cells of examined rainbow trout had an average telomere length between 17 and 20 kb, comparable in females and males. Dwarf rainbow trout exhibited significantly lower body length and weight than their normally developed siblings even though no differences in the telomere length were found between these fishes. Statistical analysis did not exhibit any correlation between body size and the telomere length. Equal length of telomeres observed in the studied normal and dwarf rainbow trout suggests morphological and physiological differences in fish with different growth rates do not affect dynamics of telomeric DNA. Or any variation in the telomere length might have been levelled by telomerase that in rainbow trout is active in all tissues irrespective of the individual developmental stage.

scholarly journals Sublethal Cobalt Toxicity Effects on Rainbow Trout (Oncorhynchus mykiss)

2019 ◽  
Vol 77 (4) ◽  
pp. 243-252
Author(s):  
Fereshteh Nasri ◽  
Saeed Heydarnejad ◽  
Amin Nematollahi
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Specific Growth ◽  
The Body ◽  
Cobalt Concentration ◽  
Feed Conversion ◽  
Control Value ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Toxicological Studies ◽  
Essential Trace Elements

Abstract The purpose of this study was to investigate the sublethal Co toxicity on rainbow trout (Oncorhynchus mykiss). Trout were exposed to Co and selected parameters were evaluated at intervals of 1, 15 and 30 days. Fish exposed to higher levels of Co grew slower than fish exposed to lower levels of Co. Weight gain, specific growth rate (SGR) decreased linearly with the increase of cobalt in the water. The body condition factor (CF) of fish reared in water with low cobalt concentration decreased substantially but this decrease was not significant for fish exposed to higher cobalt concentration. The values of the feed conversion ratio (FCR) increased in fish exposed to higher levels of Co. Co significantly changed the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and decreased at day 30, and in both cases this decrease was more remarkable at day 15 so that the level of AST and ALT reached the control value at day 30. The alkaline phosphatase (ALP) level also showed a remarkable 15-day decline. There was a significant increase in glucose (G) concentration in both Co-exposed groups on day 15. However, serum cholesterol (Chl) was significantly reduced on day 15 and increased on day 30; there were no significant differences in both exposed Co-groups. The triglyceride (TG) level also decreased substantially. There was no regular pattern of total protein (TP) in the serum, so that no significant differences were found in the level of TP between low and high-exposed fish. In summary, this study suggests that exposure of essential trace elements such as cobalt may change growth and biochemical parameters, and that measurement of these parameters may be used in toxicological studies to determine the general health status of fish.

Evaluation of the composition of essential fatty acids in the tissues of rainbow trout (Oncorhynchus mykiss) grown in closed water supply units

2021 ◽  
Vol 325 (4) ◽  
pp. 495-501
Author(s):  
E.A. Zykina ◽  
M.V. Gurin
Keyword(s):  
Fatty Acids ◽  
Rainbow Trout ◽  
Water Supply ◽  
Oncorhynchus Mykiss ◽  
Fish Oil ◽  
Essential Fatty Acids ◽  
The Body ◽  
Biologically Active ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Aquaculture Products

Recently, the task of artificial cultivation of especially valuable fish species in aquaculture has become more and more urgent. The value of salmon fish, and in particular rainbow trout Oncorhynchus mykiss (Walbaum, 1792) available for breeding, is largely determined by the high content of biologically active essential and polyunsaturated fatty acids of the group ω-6 and ω-3, necessary for vital activity and not synthesized by the human body. Since the natural stocks of many popular fatty fish have decreased, farmed fish can help meet consumer demand for this product. Based on this, the assessment of the content of the main ω-6 and ω-3 fatty acids in the fat of rainbow trout grown in closed-loop water supply installations (USV) was made. The fat was extracted from the fish by thermal method with further distillation by supercritical fluid extraction on the SFT-150 unit. The ratio of fatty acids in the fish oil sample was determined using the Chromatek-Kristall-5000 M hardware and software complex. The results obtained were compared with the standard for salmon fish oil “Aquaculture products” and “Wild fish”. It is established that trout cultivated in the UZV in the Penza region, in terms of the content of the main essential fatty acids, is not inferior to the quality indicators of the standard in terms of the requirements for salmon fish of “Aquaculture products”. In fish, all essential fatty acids are present in sufficient quantities, the ratio of ω-6 to ω-3 is 2.6:1, which indicates a high nutritional value of the product and allows it to be used in human food to provide the body with essential fatty acids, as well as a raw material for obtaining therapeutic and preventive products.

An alternative model to study the association of rainbow trout (Oncorhynchus mykiss L.) pathogens with the gill tissue

2002 ◽  
Vol 36 (4) ◽  
pp. 396-402 ◽  
Author(s):  
A. Decostere ◽  
K. Henckaerts ◽  
R. Ducatelle ◽  
F. Haesebrouck
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Gill Tissue ◽  
Branchial Arch ◽  
Ringer Solution ◽  
The Body ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Perfusion Model ◽  
Trout Gill ◽  
Branchial Artery

This study describes the development of a trout gill perfusion model, consisting of an excised branchial arch from rainbow trout ( Oncorhynchus mykiss L.), perfused via the afferent branchial artery and suspended in a circular organ chamber filled with Ringer solution. Different perfusion fluids were tested: Ringer, Cortland, Ringer + procaine, Ringer + adrenalin, Cortland + procaine, Cortland + adrenalin and Cortland + dextran 1% . The latter perfusion fluid proved to be satisfactory, maintaining the gill tissue in a healthy condition outside the body of the fish for at least 180 min. Using this model, the interaction of damaging agents with the trout gill tissue may be studied under carefully controlled conditions. The trout gill perfusion model leads effectively to a reduction in the number of experimental animals to be used and also involves an elimination of pain and/or suffering, which is as good as complete.

scholarly journals Effects of metribuzin on rainbow trout (Oncorhynchus mykiss)

2008 ◽  
Vol 53 (No. 6) ◽  
pp. 324-332 ◽  
Author(s):  
J. Velisek ◽  
Z. Svobodova ◽  
V. Piackova ◽  
L. Novotny ◽  
J. Blahova ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Histopathological Examination ◽  
Absolute Lymphocyte Count ◽  
Body Cavity ◽  
The Body ◽  
Control Group ◽  
Renal Tubules ◽  
Gill Lamellae ◽  
Experimental Group

The aim of this study was to assess the effect of metribuzin on rainbow trout (<I>Oncorhynchus mykiss</I>). An experimental group of fish was exposed to Sencor 70 WG pesticide product (active substance 70% of metribuzin). The acute semistatical toxicity test lasting 96 h was performed on rainbow trout juveniles. The 96hLC50 value of Sencor 70 WG was 89.3 mg/l. An examination of the haematological and biochemical profile and histopathological tissue examinations were performed on one- to two-year-old rainbow trout after 96 h of exposure to Sencor WG 70 in a concentration of 89.3 mg/l. The experimental group showed significantly lower values (<I>P</I> < 0.01) of plasma total proteins, triacylglycerols, aspartate aminotransferase, ammonia, calcium, lactate, alkaline phosphatase, erythrocyte count, haematocrit and significantly higher (<I>P</I> < 0.01) values of erythrocyte haemoglobin compared to the control group. A significant decrease (<I>P</I> < 0.01) in both the relative and absolute lymphocyte count and a significant increase (<I>P</I> < 0.01) in both the relative and absolute count of neutrophile granulocytes were also recorded in the experimental group. The histopathological examination revealed mild proliferation of goblet cells of the respiratory epithelium of secondary gill lamellae and hyaline degeneration of epithelial cells of the renal tubules of the caudal kidney. This alteration of kidney resulted in hypoproteinaemia, followed by the formation of transudate in the body cavity. The metribuzin-based Sencor WG 70 pesticide product was classified among substances harmful to fish.

Ontogenetic and ecotypic variation in the coloration and morphology of rainbow trout (Oncorhynchus mykiss) in a stream–lake system

2019 ◽  
Vol 128 (3) ◽  
pp. 681-699
Author(s):  
M C Arostegui ◽  
T P Quinn
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Phenotypic Diversity ◽  
Swimming Performance ◽  
The Body ◽  
Intraspecific Diversity ◽  
Ecotypic Variation ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Coloration Patterns ◽  
Morphological Patterns

Abstract Alternative ecotypes of diverse animal taxa exhibit distinct, habitat-specific phenotypes. Rainbow trout (Oncorhynchus mykiss), a salmonid fish, exhibits stream-resident (fluvial), lake-migrant (adfluvial) and ocean-migrant (anadromous) ecotypes throughout its range. We investigated the coloration, and morphology associated with swimming performance of wild, native non-anadromous rainbow trout in connected stream and lake habitats of a south-west Alaskan watershed to assess if they exhibited phenotypic diversity consistent with the presence of alternative fluvial and adfluvial ecotypes. Colour differences among rainbow trout of different size classes and habitats (stream or lake) indicated ecotype-specific pathways, diverging at the same point in ontogeny and resulting in different terminal coloration patterns. Specifically, lake-caught fish exhibited distinct silvering of the body, whereas stream-caught fish displayed banded coloration when small and bronze colour when larger. The morphology of lake-caught rainbow trout also differed from that of stream-caught fish in features associated with swimming performance, and they exhibited both shared and unique morphological patterns compared to sympatric Salvelinus species in those habitats [Dolly Varden (S. malma) in streams, and Arctic char (S. alpinus) in the lake]. Greater morphological variation within stream- than lake-caught rainbow trout, and their limited overlap in morphology, suggested population-specific partial migration. This study highlights the intraspecific diversity of migratory behaviour and how conservation of particular phenotypes depends on managing both for genotypes and for habitats.

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