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1.
In order to confirm previous observations in which a protective effect of rainbow trout natural antibodies against furunculosis was suspected, phagocytosis studies wereconducted in vitro , using combinations of rainbow trout sera with high or low levels of natural antibodies and active or inactivated complement as opsonizing factors. Opsonization was observed in all the cases where complement was present, and to a lesser degree with sera containing only natural antibodies. The results confirm the prime importance of the complement system and provide additional evidence for a possible role of natural antibodies in antimicrobial defences.  相似文献   

2.
Salmonid whirling disease caused by the metazoan parasite Myxobolus cerebralis is an ongoing problem in wild and farmed rainbow trout Oncorhynchus mykiss populations. Rainbow trout from different strains vary in susceptibility to the parasite. Identification of underlying mechanisms could be a starting point for improved control of the disease. We conducted infection trials using 2 rainbow trout strains and brown trout Salmo trutta fario, a species not susceptible to the parasite, to investigate host immune response and resistance mechanisms. We compared expression levels of 2 natural resistance-associated macrophage proteins (Nramp alpha and beta) after infection with M. cerebralis. Total RNA was extracted from skin, muscle, kidney, head and spinal column, and gene expression was quantified by real-time PCR. Significant decreases in expression of both genes were observed at different time points in the infected susceptible rainbow trout compared to the non-infected group. Furthermore, the OmNramp alpha (O. mykiss natural resistance-associated macrophage protein alpha) sequences in 2 resistant and 1 non-resistant rainbow trout strain were analysed and compared for sequence aberrations.  相似文献   

3.
4.
Dimethyl-acetamide was evaluated as a cryoprotectant for rainbow trout (Oncorhynchus mykiss ) semen on the basis of motility, percentage of dead spermatozoa as determined by fluorometry, and fertility of frozen-thawed spermatozoa. Dimethyl-acetamide performed significantly better (P<0.05) than the conventional cryoprotectant, dimethyl sulfoxide, by all evaluation methods. An extender comprised of 0.137 M NaCl, 0.011 M KCl, 0.004 M Na(2)HPO(4) 7H(2)O, 7.5 g/l L-alpha-lecithin and 10 % DMA showed promise for cryopreserving rainbow trout spermatozoa. Future evaluation of new extenders should be carried out by several in vitro techniques and fertility measurements to present a complete assessment of an extender's ability to cryopreserve sperm cells.  相似文献   

5.
Poor water quality is discussed as a major factor causing a decline of brown trout populations in Swiss rivers. For our study we have chosen a river in the Swiss midlands, where the brown trout population has decreased dramatically during the last 10 yr and where feral fish have shown distinctive pathological alterations. The objective of our study was to investigate whether river water may be responsible for impaired fish health leading to an increased mortality in the river. In an active monitoring program, groups of brown and rainbow trout were exposed to polluted river water for 24 mo. Fish held in tap water served as a reference. Mortality, macroscopic and histopathologic changes, and infectious agents were investigated. Compared with the reference group, high mortality rates and severe pathological alterations of the inner organs were observed in fish held in river water. Especially gills, liver and kidney of these fish showed significantly higher changes than fish from tap water. These changes were dominated by degenerative and inflammatory reactions. Additionally, several infectious agents were diagnosed in fish exposed to river water. The most important findings were furunculosis and proliferative kidney disease. Brown trout seemed to be more sensitive than rainbow trout to environmental stress and infectious agents.  相似文献   

6.
The susceptibility of rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta to Myxobolus cerebralis, the cause of salmonid whirling disease, was assessed following dosed exposures to the infectious stages (triactinomyxons). Parallel groups of age-matched brown trout and rainbow trout were exposed to 10, 100, 1000 or 10,000 triactinomyxons per fish for 2 h and then placed in aquaria receiving single pass 15 degrees C well water. Severity of infection was evaluated by presence of clinical signs (whirling and/or black tail), prevalence of infection, severity of microscopic lesions, and spore counts 5 mo after exposure. Clinical signs of whirling disease, including a darkened caudal region (black tail) and radical tail chasing swimming (whirling), occurred first among rainbow trout at the highest dose at 6 to 7 wk post exposure. Black tail and whirling occurred among rainbow trout receiving 1000 and 100 triactinomyxons per fish at 8 to 9 wk post exposure. Only 1 of 20 fish had a black tail among rainbow trout receiving 10 triactinomyxons per fish, although 30% of the fish were infected at 5 mo post exposure. Black tails were observed in brown trout at 1000 and 10,000 triactinomyxons per fish beginning at 11 and 7 wk post exposure, respectively. There was no evidence of the tail chasing swimming (whirling) in any group of brown trout. The prevalence of infection, spore numbers, and severity of microscopic lesions due to M. cerebralis among brown trout were less at each exposure dose when compared to rainbow trout. Infections were found among rainbow trout at all doses of exposure but only among brown trout exposed to doses of 100 triactinomyxons per fish or greater. Risk of infection analyses showed that rainbow trout were more apt to be infected at each exposure dose than brown trout. Spore counts reached 1.7 x 10(6) per head among rainbow trout at the highest dose of exposure compared to 1.7 x 10(4) at the same exposure dose among brown trout. Spore numbers increased with dose of exposure in rainbow trout but not in brown trout. As microscopic lesion scores increased from mild to moderate, spore numbers increased in rainbow trout but not brown trout. The mechanisms by which brown trout resist infections with M. cerebralis were not determined. Cellular immune functions, including those of eosinophilic granular leukocytes that were more prominent in brown trout than rainbow trout, may be involved.  相似文献   

7.
The susceptibility of 2 strains of rainbow trout Oncorhynchus mykiss, 1 from North America (TL) and 1 from Germany (GR), to Myxobolus cerebralis (the cause of salmonid whirling disease) was assessed following exposure to the infectious stages (triactinomyxons). Two laboratory experiments were conducted with age-matched rainbow trout of each strain. At the beginning of the study, the 2 trout strains were aged ca. 570 degree-days in Expt 1, and ca. 999 degree-days in Expt 2. In both experiments, replicate groups of each trout strain were exposed to 10, 100, 1000 or 10000 triactinomyxons (TAMs) fish(-1) for 2 h. The fish were then held in aquaria receiving 15 degrees C well-water. Severity of infection was evaluated 5 mo after exposure by presence of clinical signs (whirling and/or black tail), prevalence of infection, severity of microscopic lesions, and spore counts. Clinical signs of whirling disease were evident only in the younger fish exposed in Expt 1: These occurred first among TL rainbow trout at the highest dose at 6 to 7 wk post exposure and then 2 wk later in fish at the 1000 TAMs dose. Black tail was also observed among GR rainbow trout at the 10000 TAMs dose only, but in fewer fish. The prevalence of infection, spore numbers, and severity of microscopic lesions due to M. cerebralis among GR rainbow trout were less at all doses compared to TL rainbow trout. Risk of infection analyses showed that TL rainbow trout were more prone to infection at the lower doses than GR trout. Mean spore counts were consistently (10- to 100-fold) less in GR than TL trout at doses of 1000 TAMs or lower. Microscopic lesions increased with increasing dose in both strains of rainbow trout. The mechanisms underlying the greater resistance of the GR strain to M. cerebralis infections are unknown, but are under investigation as part of a long-term project to determine the basis for resistance and susceptibility of salmonid fishes to whirling disease.  相似文献   

8.
In the study, the combination of protein fractionation by 1DE and HPLC‐ESI‐MS/MS was used to characterize the rainbow trout seminal plasma proteome. Our results led to the creation of a catalogue of rainbow trout seminal plasma proteins (152 proteins) and significantly contributed to the current knowledge regarding the protein composition of fish seminal plasma. The major proteins of rainbow trout seminal plasma, such as transferrin, apolipoproteins, complement C3, serum albumin, and hemopexin‐, alpha‐1‐antiproteinase‐, and precerebellin‐like protein, were recognized as acute‐phase proteins (proteins that plasma concentration changes in response to inflammation). This study provides the basis for further functional studies of fish seminal plasma proteins, as well as for the identification of novel biomarkers for sperm quality. The MS data have been deposited in the ProteomeXchange with identifier PXD000306 ( http://proteomecentral.proteomexchange.org/dataset/PXD000306 ).  相似文献   

9.
We examined the developmental rate of hybrids between rainbow trout (Salmo gairdneri) and two subspecies of cutthroat trout: westslope cutthroat trout (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri). These taxa show considerable genetic divergence at 42 structural loci encoding enzymes; the mean Nei's d between the rainbow trout and the two species of cutthroat trout is 0.22. We used four measures of developmental rate: time of hatching and yolk resorption, rate of increase in activity of four enzymes, and time of initial detection of seven isozyme loci. The two cutthroat trout subspecies reached hatching and yolk resorption earlier than rainbow trout. Cutthroat trout had higher relative enzyme activities than rainbow trout from deposition of eye pigment to hatching. There was no difference in the rate of increase in enzyme activity or time of initial expression of these loci between these species. Hybrids showed developmental rates intermediate or similar to that of the parental species using all measures. Our results indicate an absence of regulatory and developmental incompatibility between these taxa.This research was supported by NSF Grants ISP-8011449 and BSR-8300039. M.M.F. was supported by a postgraduate scholarship from the Natural Sciences and Engineering Research Council of Canada.  相似文献   

10.
Comparative analysis of two Nramp loci from rainbow trout.   总被引:8,自引:0,他引:8  
Innate resistance to intracellular parasites is controlled in part by Nramp1 (Natural resistance-associated macrophage protein 1) in mammals and birds. To isolate Nramp homologs from rainbow trout, a combination of library screening and rapid amplification of cDNA ends was performed. Two closely related Nramp loci, designated OmNramp alpha and OmNramp beta, were cloned and characterized. OmNramp alpha and OmNramp beta encode two highly conserved proteins of 585 and 558 amino acids, respectively. Deduced amino acid seqences showed that the OmNramp alpha and OmNramp beta proteins share 90% of their residues and contain all of the signature features of the Nramp family of proteins: 12 transmembrane domains, two N-linked glycosylation sites, and a conserved transport motif. Phylogenetic analysis supported a close relation to Nramp2 proteins, a related member of the Nramp family. Despite this relation, juvenile trout expressed OmNramp alpha in a manner consistent with an Nramp1 homolog and OmNramp beta similar to an Nramp2 locus. Both trout loci were expressed at relatively high amounts in the ovaries of juveniles, a finding not reported in the investigations of previously characterized mammalian and avian homologs. These results suggest a role for Nramp loci in the follicular development of teleost fishes, as well as in mammals. Because salmonid fishes are ancestral tetraploids, fragments of OmNramp alpha and OmNramp beta were isolated from smelt, a diploid relative, to determine whether the trout loci represent duplicates of a single gene. Homologous sequences for both loci were found in smelt, supporting the hypothesis that OmNramp alpha and OmNramp beta are indeed independent loci that were present before the chromosomal duplication of salmonids. The isolation of Nramp loci from rainbow trout may eventually produce a genetic tool for the control of disease in aquaculture operations. Determining the involvement of trout homologs in innate immunity may also provide insight regarding the evolution of host resistance to pathogens.  相似文献   

11.
Five genetic markers previously shown to be located on the sex chromosomes of rainbow trout (Oncorhynchus mykiss) were tested for linkage with the sex locus of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) in a genetic cross created from a rainbow x cutthroat male hybrid. We show that the sex locus of both rainbow and cutthroat trout is on the same homologous linkage group. Fluorescence in situ hybridization (FISH) using a probe for the microsatellite marker Omm1665, which maps close to the sex locus of Yellowstone cutthroat trout, was used to identify the Y chromosome of cutthroat trout in the hybrid. The Y chromosome of cutthroat trout is sub-telocentric and lacks a DAPI band found on the short arm of the Y chromosome of some rainbow trout males.  相似文献   

12.
Silver-banded karyotypes of the rainbow trout Salmo gairdneri, the brook trout Salvelinus fontinalis, and their hybrids were described. Diploid-type and triploid-type hybrids were obtained. Triploid-type hybrids had two maternal genomes of the rainbow trout and one paternal genome of the brook trout. The rainbow trout had one pair of M or SM with Ag-NORs near the satellite. In the brook trout, Ag-NORs were observed in four pairs of chromosomes, but each cell had different number of chromosomes with Ag-NORs. In all observed cells of triploid-type hybrids, Ag-NORs originated from the brook trout were not recognized, whereas those from the rainbow trout were found.  相似文献   

13.
Recently a number of cytokine homologs have been cloned in teleost fish, including several that resemble chemokines, but to date few have been confirmed using functional assays. Chemokines are a family of cytokines that are able to induce chemotaxis in leucocytes. In this study CK-1, a rainbow trout chemokine, was functionally characterised. Recombinant CK-1 is able to attract rainbow trout peripheral blood leucocytes (PBL) in a micro-chemotaxis chamber. A greater number of PBLs migrated in response to CK-1 than to negative controls, either media alone or equivalent concentrations of beta2M, while comparable numbers migrated to the positive control, recombinant human C5a. The tissue distribution of CK-1 mRNA was also assessed by Northern blotting of RT-PCR and showed that expression is constitutive in the liver and gut, and is inducible by intraperitoneal injection of phytohemagglutinin in PBL and the head-kidney. Continuous cell lines generated from the gut and pituitary gland of the rainbow trout also express CK-1 message, whilst Southern analysis shows that CK-1 is a single copy gene. Finally, CK-1 shows the greatest amino acid similarity CCL20/LARC/Mip-3alpha as well as similar gene structure and expression pattern.  相似文献   

14.
15.
As part of our efforts to characterize Na,K-ATPase isoforms in salmonid fish, we investigated the linkage arrangement of genes coding for the alpha and beta-subunits of the enzyme complex in the tetraploid-derived genome of the rainbow trout (Oncorhynchus mykiss). Genetic markers were developed from four of five previously characterized alpha-subunit isoforms (alpha1b, alpha1c, alpha2 and alpha3) and four expressed sequence tags derived from yet undescribed beta-subunit isoforms (beta1a, beta1b, beta3a and beta3b). Sex-specific linkage analysis of polymorphic loci in a reference meiotic panel revealed that Na,K-ATPase genes are generally dispersed throughout the rainbow trout genome. A notable exception was the colocalization of two alpha-subunit genes and one beta-subunit gene on linkage group RT-12, which may thus share a conserved orthologous segment with linkage group 1 in zebrafish (Danio rerio). Consistent with previously reported homeologous relationships among the chromosomes of the rainbow trout, primers designed from the alpha3-isoform detected a pair of duplicated genes on linkage groups RT-27 and RT-31. Similarly, the evolutionary conservation of homeologous regions on linkage groups RT-12 and RT-16 was further supported by the map localization of gene duplicates for the beta1b isoform. The detection of homeologs within each gene family also raises the possibility that novel isoforms may be discovered as functional duplicates.  相似文献   

16.
Susceptibility to different diseases among related species, such as coho salmon (Oncorhynchus kisutch), rainbow trout (Oncorhyncus mykiss) and Atlantic salmon (Salmo salar), is variable. The prominence of these species in aquaculture warrants investigation into sources of this variability to assist future disease management. To develop a better understanding of the basis for species variability, several important non-specific humoral parameters were examined in juvenile fish of these three economically important species. Mucous protease, alkaline phosphatase and lysozyme, as well as plasma lysozyme activities and histological parameters (epidermal thickness and mucous cell density, and size) were characterized and compared for three salmonids: rainbow trout, Atlantic salmon and coho salmon. Rainbow trout had a thicker epidermis and significantly more mucous cells per cross-sectional area than the other two species. Rainbow trout also had significantly higher mucous protease activity than Atlantic salmon and significantly higher lysozyme (plasma and mucus) activities than coho and Atlantic salmon, in seawater. Atlantic salmon, on the other hand, had the lowest activities of mucous lysozyme and proteases, the thinnest epidermal layer and the sparsest distribution of mucous cells, compared with the two other salmonids in seawater. Only coho salmon had sacciform cells. Atlantic and coho salmon had higher mucous lysozyme activities in freshwater as compared to seawater. There was no significant difference between mucous lysozyme activities in any of the three species reared in freshwater; however, rainbow trout still had a significantly higher plasma lysozyme activity compared with the other two species. All three species exhibited significantly lower mucous alkaline phosphatase and protease activities in freshwater than in seawater. Our results demonstrate that there are significant histological and biochemical differences between the skin and mucus of these three salmonid species, which may change as a result of differing environments. Variation in these innate immune factors is likely to have differing influences on each species response to disease processes.  相似文献   

17.
In rainbow trout (Salmo gairdnerii) lipoprotein profiles change during the annual sexual cycle. Among other factors, lipoprotein lipase (LPL) activity might play a role. This enzyme is activated by trout serum suggesting the existence of a cofactor corresponding to apoprotein CII in this species. In the present study, we determined more accurately some characteristics of the enzyme activity inhibited by 0.3 M NaCl. Trout serum and high density lipoproteins (HDL) activated both rat and trout adipose tissue LPLs. A fraction of apo HDL obtained by gel filtration also activated the enzyme. The mean Mr was 10,000. Isoelectric focusing of the same fraction gave several bands of proteins with apparent pI in the range of 4.2-4.9. These results show that in trout, LPL is activated by a cofactor similar to that in mammals, the apo CII. In addition, a fraction mainly containing apo AI (+ traces of apo C) activated trout LPL and reinforced the activation by apo CII. These findings suggest that trout apo AI may promote the activating effect of apo CII on trout LPL.  相似文献   

18.
To assess the influence of water temperature on silver uptake, rainbow trout Oncorhynchus mykiss ( c . 50 g; held at 13° C) were exposed to 0·1 μM AgNO3 in ion‐poor water for 1 week at 4 and 16° C without previous temperature acclimation. To assess the influence of temperature on elimination of previously accumulated Ag, rainbow trout were exposed to 0·1 μM AgNO3 in ion‐poor water for 1 week at 12° C, then were randomly divided amongst two Ag‐free water containers, differing only in temperature (3 and 16° C), for 2 months. In the uptake study greater accumulation of Ag was seen in the gills, plasma and especially the livers and bile of 'warm' rainbow trout (16° C) compared to 'cold' rainbow trout (4° C), which can be explained by the higher metabolic rates of the warmer fish. In the depuration study there was no net elimination of Ag from the livers and bile but there was biphasic elimination of Ag from the gills and plasma of 'warm' and 'cold' fish, but with few differences between them. This indicated that temperature‐dependent processes were less important in Ag elimination than in Ag uptake. Toxicokinetic modelling of Ag uptake by livers indicated four‐fold greater uptake of Ag by 'warm' rainbow trout compared to 'cold' rainbow trout (one compartment uptake model). Elimination of previously accumulated Ag from the plasma was best fitted by a two compartment rate‐constant based model, with approximately half the plasma Ag load eliminated within 24 h, followed by slower elimination of Ag over 2 months.  相似文献   

19.
Newly formed hybrid populations provide an opportunity to examine the initial consequences of secondary contact between species and identify genetic patterns that may be important early in the evolution of hybrid inviability. Widespread introductions of rainbow trout (Oncorhynchus mykiss) into watersheds with native cutthroat trout (Oncorhynchus clarkii) have resulted in hybridization. These introductions have contributed to the decline of native cutthroat trout populations. Here, we examine the pattern of hybridization between introduced rainbow trout and 2 populations of cutthroat trout native to Colorado. For this study, we utilized 7 diagnostic, codominant nuclear markers and a diagnostic mitochondrial marker to investigate hybridization in a population of greenback cutthroat trout (Oncorhynchus clarkii stomias) and a population of Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus). We infer that cutthroat-rainbow trout hybrid swarms have formed in both populations. Although a mixture of hybrid genotypes was present, not all genotype combinations were detected at expected frequencies. We found evidence that mitochondrial DNA introgression in hybrids is asymmetric and more likely from rainbow trout than from cutthroat trout. A difference in spawning time of the 2 species or differences in the fitness between the reciprocal crosses may explain the asymmetry. Additionally, the presence of intraspecific cytonuclear associations found in both populations is concordant with current hypotheses regarding coevolution of mitochondrial and nuclear genomes.  相似文献   

20.
The occurrence of Hexamita salmonis Moore, 1922 and Loma salmonae Putz, Hoffman and Dunbar, 1965 was investigated at 10 sites on the R. Itchen (five for brown trout only, three for rainbow trout only, and two for both brown trout and rainbow trout) and at three of its nine fish farms (two for rainbow trout, one for brown trout). Hexamita salmonis was recorded in brown trout from three river sites and the farm, and in rainbow trout from both farms and four river sites. Prevalence of Hexamita salmonis in farmed rainbow trout was higher than in farmed brown trout and was consistent with the former species being more susceptible to infection. H. salmonis was at significantly higher prevalence in rainbow trout from farm no. 5 than farm no. 2 for three size classes of fish. In wild brown trout and feral rainbow trout, the highest prevalences of H. salmonis were recorded at sites in the vicinity of farm no. 2. This distribution was consistent with an area of naturally high infection levels, and with infected fish unintentionally released from farm no. 2 serving as a source of infection, the infection subsequently becoming established in the river fish. Loma salmonae was recorded in wild brown trout and in rainbow trout from both farms. This appears to be the first recording of this parasite from British salmonids and also the first recording of the parasite from brown trout. The distribution of the parasite (particularly the prevalence being higher at farm no. 2 than farm no. 5) was consistent with it being introduced into the R. Itchen via rainbow trout from farm no. 2 (and probably no. 3) much of whose stock derived from imported Californian 'Shasta' rainbow trout.  相似文献   

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