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At least 19 recordsLinked to original sources
PubMed1983

The immunocytochemical localization of pituitary somatotrops in the genus Oncorhynchus using an antiserum to growth hormone of chum salmon (Oncorhynchus keta).

Pituitary somatotrops were localized in four species from the genus Oncorhynchus using an antiserum to chum salmon (Oncorhynchus keta) growth hormone. The antiserum cross-reacted specifically with the acidophils in the caudal pars distalis of all species tested. Corroborative immunodiffusion studies were also conducted with pituitary homogenates from the same species. Immunological identity of the GH molecule was observed for all species tested.

Animals↗
PubMed1981

Quantitative interlake comparison of thyroid pathology in Great Lakes coho (Oncorhynchus kisutch) and chinook (Oncorhynchus tschawytscha) salmon.

Coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha) from Lakes Ontario, Michigan, Erie, or Huron were found to suffer epizootics of thyroid hyperplasia and goiters which appeared to have an environmental etiology. There were 13-fold differences in goiter prevalence within the Great Lakes, and the differences in goiter frequency were correlated with the degree of thyroid hyperplasia. A means of assessing the degree of thyroid hyperplasia (thyroid index) is described, and the derived index was used to facilitate statistical interlake and interspecies comparisons. Despite the hyperplastic (or goitered) condition in all prespawning or spawning Great Lakes salmon, serum thyroid hormone levels were generally higher than in prespawning coho salmon from the Fraser River, British Columbia, indicating that the Great Lakes fish were not necessarily hypothyroid. The hyperplastic lesions appear to undergo progressive changes: (a) large follicles, partly colloid depleted, surrounded by cuboidal epithelial cells; (b) small follicles, largely colloid depleted, surrounded by columnar epithelial cells (in this form, the follicles commonly assume a trabeculate arrangement); (c) "microfollicles" with greatly enlarged columnar epithelial cells encompassing very small follicles; (d) apparently afollicular lesions with little or no colloid in evidence. There was some evidence of benign invasiveness, although the lesions generally resembled simple hyperplastic parenchymatous goiters seen in humans.

Animals↗
PubMed2002

Susceptibility of rainbow trout Oncorhynchus mykiss, Atlantic salmon Salmo salar and coho salmon Oncorhynchus kisutch to experimental infection with sea lice Lepeophtheirus salmonis.

Physiological, immunological and biochemical parameters of blood and mucus, as well as skin histology, were compared in 3 salmonid species (rainbow trout Oncorhynchus mykiss, Atlantic salmon Salmo salar and coho salmon O. kisutch) following experimental infection with sea lice Lepeophtheirus salmonis. The 3 salmonid species were cohabited in order to standardize initial infection conditions. Lice density was significantly reduced on coho salmon within 7 to 14 d, while lice persisted in higher numbers on rainbow trout and Atlantic salmon. Lice matured more slowly on coho salmon than on the other 2 species, and maturation was slightly slower on rainbow trout than on Atlantic salmon. Head kidney macrophages from infected Atlantic salmon had diminished respiratory burst and phagocytic capacity at 14 and 21 d post-infection (dpi), while infected rainbow trout macrophages had reduced respiratory burst and phagocytic capacities at 21 dpi, compared to controls. The slower development of lice, coupled with delayed suppression of immune parameters, suggests that rainbow trout are slightly more resistant to lice than Atlantic salmon. Infected rainbow trout and Atlantic salmon showed increases in mucus lysozyme activities at 1 dpi, which decreased over the rest of the study. Mucus lysozyme activities of infected rainbow trout, however, remained higher than controls over the entire period. Coho salmon lysozyme activities did not increase in infected fish until 21 dpi. Mucus alkaline phosphatase levels were also higher in infected Atlantic salmon compared to controls at 3 and 21 dpi. Low molecular weight (LMW) proteases increased in infected rainbow trout and Atlantic salmon between 14 and 21 dpi. Histological analysis of the outer epithelium revealed mucus cell hypertrophy in rainbow trout and Atlantic salmon following infection. Plasma cortisol, glucose, electrolyte and protein concentrations and hematocrit all remained within physiological limits for each species, with no differences occurring between infected and control fish. Our results demonstrate that significant differences in mucus biochemistry and numbers of L. salmonis occur between these species.

Alkaline Phosphatase↗
PubMed1983

In vivo antiviral effect of 9-(2-hydroxyethoxymethyl) guanine on experimental infection of chum salmon (Oncorhynchus keta) fry with Oncorhynchus masou virus (OMV).

The therapeutic efficacy of 9-(2-hydroxyethoxymethyl) guanine (Acyclovir, ACV) was evaluated using Oncorhynchus masou virus (OMV) and chum salmon fry. The fish, which were experimentally infected with OMV, were treated with ACV either orally or by the immersion method. Daily immersion of fish into ACV solution (25 microgram/ml, 30 min/day, 15 times) reduced mortality of the infected fish. Oral administration of the drug (25 microgram/fish per day, 60 times) did not affect survival of the chum salmon. On the contrary, the group administered 5-iodo-2'-deoxyuridine (IUdR) by the oral route showed a higher survival than the ACV-administered group. This suggested that an effective level of ACV was not maintained in fish given the drug by the oral route. Daily immersion of infected fish into ACV solution (25 microgram/ml, 30 min/day, 60 times) considerably suppressed the development of tumors induced by OMV.

Acyclovir↗
PubMed2002

The effects of thyroxine or a GnRH analogue on thyroid hormone deiodination in the olfactory epithelium and retina of rainbow trout, Oncorhynchus mykiss, and sockeye salmon, Oncorhynchus nerka.

Using low (0.5nM) substrate levels we determined the activities of thyroxine (T4) outer-ring deiodination (ORD), T4 inner-ring deiodination (T4IRD) and 3,5,3(')-triiodothyronine (T3) IRD activities in the olfactory epithelium (OLF) and retina (RET) of laboratory-held immature 1-year-old rainbow trout and immature 2.5-year-old sockeye salmon. In both species all three deiodination activities were detected in OLF and RET. For OLF, no particular pathway predominated and activities were similar to those of brain. For RET, T3IRD activity was greater than T4ORD activity and in sockeye RET T3IRD activity exceeded that of liver. Trout immersion for 6 weeks in 100ppm T4 increased plasma T4 levels 3-fold and plasma T3 levels by 50% and caused the anticipated autoregulatory responses in brain and liver deiodination ( downward arrow T4ORD, upward arrow T4IRD, and upward arrow T3IRD); OLF deiodination and RET T4ORD activity were unaltered but RET T4IRD and T3IRD activities increased dramatically. Two injections of a GnRH analogue (20 microgkg(-1)) into sockeye increased plasma T3 levels but not T4 levels and decreased RET T4IRD and T3IRD activities without changing liver, brain, or OLF deiodination. We conclude that in salmonids the main TH deiodination pathways occur in OLF but show no regulation by T4 or GnRH. In contrast, T3IRD activity predominates in RET and can be regulated by T4 and GnRH, suggesting that for RET plasma may be the major T3 source. These findings have implications for thyroidal regulation of sensory functions during salmonid diadromous migrations.

Animals↗
PubMed2000

In vivo effect of EICAR (5-ethynyl-1-beta-D-ribofuranosylimidazole-carboxamide) on experimental infected rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch) fry with infectious pancreatic necrosis virus.

The in vivo antiviral effect of 5-ethynyl-1-beta-D-ribofuranosylimidazole-carboxamide (EICAR) was evaluated in coho salmon and rainbow trout fry, experimentally infected with infectious pancreatic necrosis virus (IPNV). Treatment consisted of a daily bath of 2 h in 0.4 microg ml(-1) or 0.8 microg ml(-1) of EICAR, for approximately 20 days. The behavior of the fish was studied for 45 days post-infection. The survival of the infected treated groups was compared with the survival of non-infected and infected untreated control groups. The results showed that the survival of coho salmon and rainbow trout fry in the infected group treated with both doses of EICAR was similar to the survival observed in the healthy control group (approximately 94%). While, the survival of the infected and untreated control fish was 56% for salmon and 28% for trout, there were no significant difference in the weight of coho salmon fry between those treated with EICAR and non-infected and infected untreated control groups. However, in rainbow trout there was a statistically significant weight decrease in infected untreated group. Finally, the analysis of tissue samples of the fish by reverse transcription associated with the polymerase chain reaction (RT-PCR) suggest that EICAR have decreased the viral load in infected treated fry. Consequently, the results indicate that EICAR is an effective inhibitor of IPNV replication in vivo and could be a promissory antiviral compound for the treatment of IPNV disease.

Animals↗
PubMed2001

PCB congeners in Lake Michigan coho (Oncorhynchus kisutch) and chinook (Oncorhynchus tshawytscha) salmon.

We determined PCB congener concentrations in coho and chinook salmon collected in two Lake Michigan tributaries during the fall of 1996. Chinook salmon were larger than coho salmon and contained higher concentrations of the 78 PCB congeners we detected. There were no differences between male and female chinook or coho salmon in size or their PCB concentrations. Among individual fish, we found little evidence for a relationship between congener concentrations and percent lipid; however, congener concentrations did show a generally positive relationship with salmon size. Fish and macroinvertebrate congener concentrations are clearly related, and PCB congeners biomagnify approximately 20-30-fold as they flow from macroinvertebrates, two trophic levels below salmon, to the salmon. Slopes of regressions of salmonid congener concentrations on macroinvertebrate congener concentrations within homologs indicated that the degree of biomagnification generally increased with the degree of congener chlorination, although this pattern was much stronger for Mysis than for Diporeia. Log Kow and categorical variables for coplanar and "toxic" PCBs were not significant additional model terms, indicating that bioaccumulation of PCB congeners was not statistically related to these physicochemical attributes of the PCBs. The distribution of homologue PCBs shifts from a distinct predominance of hexachlorobiphenyls in macroinvertebrates to pentachlorobiphenyls and hexachlorobiphenyls in the salmon.

Animals↗
PubMed1995

[The thyroid gland of humpback salmon (Oncorhynchus gorbuscha) fry and of humpback and cherry salmon (Oncorhynchus masu) hybrids during smoltification].

Thyroid gland follicular cells were studied morphofunctionally on different stages of juvenile humpback salmon migration from the spawning sites into the sea. Salmon hybrids kept in laboratory conditions in fresh and salt water were exposed to the same examination. Juvenile humpback salmon fished out from the river mouth, when coming to the sea water had significant increase of follicular epithelium height and decrease of follicular diameter and amount of the deponated colloid. Thyroid glands follicle topography of hybrids is close to those of juvenile humpback salmon although it is more compact in hybrids. Completely formed follicles were found in three-month-old fish. Microscopic and morphometric studies revealed the increase of thyroid gland activity in hybrids in April: follicular diameter grew smaller, epithelial height significantly increased and amount of colloid in the follicles decreased. In May increased activity of the gland remained and went smaller in June. Ten days after hybrids transferation into the sea water activity of the gland cells significantly increased. Thus, thyroid gland activity is an important characteristics of smoltification both for the juvenile salmon from natural population and hybrids kept in laboratory conditions.

Animals↗
PubMed1988

A genetic analysis of early development in pink (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) at three different temperatures.

A factorial mating design was employed in which five males were mated to each of five females in each of two stocks for both pink and chum salmon. The resulting embryos and alevins were incubated at constant water temperatures of 4, 8, and 16 degrees C for pink salmon and 3, 8, and 15 degrees C for chum salmon. Variation among families in alevin and fry survival rates, hatching, button-up time, length, and weight was the least at 8 degrees C. Heritability of traits directly correlated with fitness, such as survival rates and button-up time, was low at all temperatures (h2 less than or equal to 0.25). Maternal effects could account for a substantial portion of the variation in alevin and fry size characters. Nonadditive genetic variance accounted for more of the variation in fry size characters than in those of alevins. Negative genetic correlations were observed between embryo survival and subsequent alevin size and between hatching time and subsequent alevin and fry size. Genotype-temperature interactions could underlie a substantial amount of phenotypic variation in the developmental characters examined for both species.

Aging↗
PubMedDate not supplied

[Changes in the content of 11-oxycorticosteroids in the blood serum of the spawning Siberian salmon Oncorhynchus keta and humpback salmon Oncorhynchus gorbuscha].

Studies have been made on 11-oxycorticosteroid content of the blood serum in spawning salmons. During sexual maturation and spawning migration, the level of 11-oxycorticosteroids in the blood serum undergoes significant changes. The pattern of these changes is similar in both of the species investigated. During fresh-water period of migration, 11-3xycorticosteroid content in the blood serum of females of O. gorbuscha is 3 times higher as compared to that during sea-water period. In O. keta, this level increases two-fold. The increased content of 11-oxycorticosteroids remains constant up to spawning. After the latter, the level of 11-oxycorticosteroids decreases reaching the values typical for sea-water period.

Adrenal Cortex Hormones↗
PubMed1984

[Demonstration of specific gonadotropin binding sites of chum salmon (Oncorhynchus keta) in membrane preparations of granulosa cells from the ovary of amago salmon (Oncorhynchus rhodurus)].

During late vitellogenesis, radioactive iodine labelled Salmon gonadotropin binds to theca--or granulosa--membrane preparations from amago Salmon ovary. In granulosa, native hormone inhibits iodinated GTH binding, thus indicating a specific binding (70% of total binding). In theca, a lower specific binding is found while non specific binding is higher: contamination by granulosa cells, on one hand, the possible heterogeneity of theca, on the other, could account for these results.

Animals↗
PubMed1984

Detection of infection and susceptibility of different Pacific salmon stocks (Oncorhynchus spp.) to the haemoflagellate Cryptobia salmositica.

The haematocrit centrifugation technique, modified by keeping the haematocrit tubes cold (between 1 and 10 C), was sensitive for detecting light infections of Cryptobia salmositica (as few as 75 flagellates per ml of blood). In wet mount preparations, infections lighter than 7.5 X 10(3) flagellates per ml of blood could not be detected consistently. Different Pacific salmon stocks from British Columbia demonstrated differences in susceptibility to C. salmositica in experimental studies using laboratory reared juvenile fish. Oncorhynchus keta and Oncorhynchus tshawytscha from the Big Qualicum River stocks (Vancouver Island), and Oncorhynchus nerka from the Fulton River stock (Skeena River system), were all equally susceptible and suffered high mortalities at low exposures (100 flagellates in 0.1 ml physiological saline inoculated intraperitoneally per fish). Oncorhynchus nerka from the Weaver Creek stock (Fraser River system) was the most resistant with no mortalities even at exposures of 10(6) flagellates (in 0.1 ml physiological saline) per fish. Oncorhynchus kisutch seemed to be slightly less resistant than the Weaver Creek O. nerka, but fewer than 16% of the inoculated fish died. Oncorhynchus kisutch from the Big Qualicum River seemed to be slightly more resistant than O. kisutch from the Capilano River stock (a coastal river near Vancouver), with fewer mortalities and lighter infections when the experiments were terminated. Differences in susceptibility are believed to be associated with innate, genetically transmitted resistance.

Animals↗
PubMed1995

Phylogenetic analysis of Pacific salmon (genus Oncorhynchus) based on mitochondrial DNA sequence data.

Previous phylogenetic analyses of the fishes belonging to the genus Oncorhynchus based on mitochondrial DNA data have produced conflicting trees. This is especially true with respect to the relationships among the three most derived Pacific salmon species, the pink salmon (Oncorhynchus gorbuscha), sockeye salmon (Oncorhynchus nerka), and chum salmon (Oncorhynchus keta). Smith (Syst. Biol. 41(1): 41-57, 1992) suggested that introgression in opposite directions on either side of the Pacific ocean may account for some of the conflicting data. The ATPase 6 and ND3 mitochondrial genes were sequenced from Asian and North American representatives of several species of Pacific salmon and the aligned sequences were analyzed along with other data on these genes. Analysis of the ATPase 6 and ND3 sequence data and RFLP data gives strong support for a sister relationship between pink salmon and chum salmon.

Adenosine Triphosphatases↗