11 research outputs found
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Sablefish (Anoplopoma fimbra Pallas, 1814) plasma biochemistry and hematology reference intervals including blood cell morphology
Plasma biochemistry and hematology reference intervals are integral health assessment tools in all medical fields, including aquatic animal health. As sablefish (Anoplopoma fimbria) are becoming aquaculturally and economically more important, this manuscript provides essential reference intervals (RI) for their plasma biochemistry and hematology along with reference photomicrographs of blood cells in healthy, fasted sablefish. Blood cell morphology can differ between fish species. In addition, blood cell counts and blood chemistry can vary between fish species, demographics, water conditions, seasons, diets, and culture systems, which precludes the use of RI’s from other fish species. For this study, blood was collected for plasma biochemistry and hematology analysis between June 20 and July 18, 2019, from healthy, yearling sablefish, hatched and reared in captivity on a commercial diet. Overnight fast of 16–18 hours did not sufficiently reduce lipids in the blood, which led to visible lipemia and frequent rupture of blood cells during analysis. Therefore, sablefish should be fasted for 24 to 36 hours before blood is collected to reduce hematology artifacts or possible reagent interference in plasma biochemistry analysis. Lymphocytes were the most dominant leukocytes (98%), while eosinophils were rare, and basophils were not detected in sablefish. Neutrophils were very large cells with Döhle bodies. In mammals and avian species, Döhle bodies are usually signs of toxic change from inflammation, but no such association was found in these fish. In conclusion, lipemia can interfere with sablefish blood analysis, and available removal methods should be evaluated as fasting for up to 36 h might not always be feasible. Also, more studies are required to establish RI for different developmental stages and rearing conditions
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Cumulative Effects of Natural and Anthropogenic Stress on Immune Function and Disease Resistance in Juvenile Chinook Salmon
Previous studies have shown that juvenile chinook salmon Oncorhynchus tshawytscha exposed in the field or the laboratory to polychlorinated biphenyls (PCBs), an anthropogenic stressor, are immunosuppressed. It is not known whether simultaneous exposure to natural stressors can increase this immunosuppression. To examine the effects of natural and anthropogenic stressors on immune function, we infected juvenile chinook salmon with metacercariae of the trematode Nanophyetus salmincola by exposing the fish to infected freshwater snails Juga plicifera. Infected (>300 metacercariae per fish) and noninfected salmon were then injected with either the commercial PCB mixture Aroclor 1254 or an acetone-emulphor carrier. B cell function was examined by in vitro hemolytic plaque-forming cell (PFC) assay. Nanophyetus salmincola infection resulted in significantly lower anterior kidney primary PFCs and lower splenic secondary PFCs. The combination of N. salmincola infection and Aroclor 1254 exposure caused a lower anterior kidney primary PFC response than did either stressor alone. The immune function of juvenile chinook salmon was also measured by challenging them with the marine bacterium Listonella anguillarum (formerly known as Vibrio anguillarum). Fish infected with N. salmincola had higher mortalities than noninfected fish when challenged with L. anguillarum. These experiments demonstrated that N. salmincola infection in juvenile chinook salmon can impair immune function and disease resistance. The findings also show that in combination these natural and anthropogenic stressors can have a greater negative effect on salmon health than either stressor alone.Keywords: stress, Oncorhynchus tshawytscha, polychlorinated biphenyls, immunosuppressio
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Increased Susceptibility of Juvenile Chinook Salmon to Vibriosis after Exposure to Chlorinated and Aromatic Compounds Found in Contaminated Urban Estuaries
Saltwater-adapted juvenile chinook salmon Oncorhynchus tshawytscha exposed to aromatic and chlorinated compounds, representative of contaminants found in urban estuaries in Puget Sound, have a higher susceptibility to vibriosis than do fish exposed only to the solvent vehicle. Susceptibility to vibriosis was assessed by examining the percent cumulative mortality of the salmon after exposure to the bacterial pathogen Vibrio anguillarum. The aromatic and chlorinated compounds examined consisted of a sediment extract from the Hylebos Waterway that was enriched in butadienelike compounds (chlorinated-enriched Hylebos Waterway sediment extract [CHWSE]), a model mixture of polycyclic aromatic hydrocarbons (PAHs), a polychlorinated biphenyl mixture (Aroclor 1254), hexachlorobutadiene (HCBD), and 7,12-dimethylbenz[a]anthracene (DMBA). Two trials were conducted. In trial l, the percent cumulative mortality of juvenile chinook salmon exposed to V. anguillarum after receiving either CHWSE, HCBD, or the model mixture of PAHs ranged from 28% to 31% compared with the 16% observed in the acetone:emulphor control group at 7 d post-bacterial challenge. In trial 2, the net cumulative mortality of juvenile chinook salmon exposed to V. anguillarum after receiving either DMBA or Aroclor 1254 ranged from 46% to 49% compared with the 25% observed in the acetone:emulphor control group at 9 d postchallenge. The differences in mortality between groups of fish in the treated and control groups in both trials were significant at P 0.05. These findings suggest that a higher predisposition to infection and subsequent disease can occur in salmon exposed to chemical contaminants found in urban estuaries of Puget Sound, WashingtonKeywords: polychlorinated-biphenyls, juveniles, Vibriosis, Oncorhynchus tshawytscha, estuarie
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Survey of Pathogens in Hatchery Chinook Salmon with Different Out-Migration Histories through the Snake and Columbia Rivers
The operation of the Federal Columbia River Power System (FCRPS) has negatively affected threatened and endangered salmonid populations in the Pacific Northwest. Barging Snake River spring Chinook salmon Oncorhynchus tshawytscha through the FCRPS is one effort to mitigate the effect of the hydrosystem on juvenile salmon out-migration. However, little is known about the occurrence and transmission of infectious agents in barged juvenile salmon relative to juvenile salmon that remain in-river to navigate to the ocean. We conducted a survey of hatchery-reared spring Chinook salmon at various points along their out-migration path as they left their natal hatcheries and either migrated in-river or were barged through the FCRPS. Salmon kidneys were screened by polymerase chain reaction for nine pathogens and one family of water molds. Eight pathogens were detected; the most prevalent were Renibacterium salmoninarum and infectious hematopoietic necrosis virus. Species in the family Saprolegniaceae were also commonly detected. Pathogen prevalence was significantly greater in fish that were barged through the FCRPS than in fish left to out-migrate in-river. These results suggest that the transmission of infectious agents to susceptible juvenile salmon occurs during the barging process. Therefore, management activities that reduce pathogen exposure during barging may increase the survival of juvenile Chinook salmon after they are released.Keywords: Oncorhynchus tshawytscha, Pacific Northwest, hatchery, pathogens, juvenile
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Survey of Pathogens in Juvenile Salmon Oncorhynchus Spp. Migrating through Pacific Northwest Estuaries
Although the adverse impact of pathogens on salmon populations in the Pacific Northwest is often discussed and recognized, little is currently known regarding the incidence and corresponding significance of delayed disease-induced mortalities. In the study reported herein, we surveyed the presence and prevalence of selected micro- and macroparasites in out-migrant juvenile coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha from 12 coastal estuaries in the Pacific Northwest over a 6-year period (1996-2001). The major finding of this study was the widespread occurrence of pathogens in wild salmon from Pacific Northwest estuaries. The six most prevalent pathogens infecting both juvenile Chinook and coho salmon were Renibacterium salmoninarum, Nanophyetus salmincola, an erythrocytic cytoplasmic virus (erythrocytic inclusion body syndrome or erythrocytic necrosis virus), and three gram-negative bacteria (Listonella anguillarum, Yersinia ruckeri, and Aeromonas salmonicida). The most prevalent pathogen in both Chinook and coho salmon was N. salmincola, followed by the pathogens R. salmoninarum and the erythrocytic cytoplasmic virus. Statistically significant differences in the prevalence of R.. salmoninarum and N. salmincola were observed between Chinook and coho salmon. Based on the prevalence of pathogens observed in this study, disease appears to be a potentially significant factor governing the population numbers of salmon in the Pacific Northwest. Development of a detailed understanding of the principal components influencing the ecology of infectious disease will aid in the development of management and control strategies to mitigate disease in and hence further the recovery of salmon stocks listed under the Endangered Species Act
Reduced cytochrome P4501A activity and recovery from oxidative stress during subchronic benzo[a]pyrene and benzo[e]pyrene treatment of rainbow trout
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Toxicology and Applied Pharmacology 254 (2011): 1-7, doi:10.1016/j.taap.2011.04.015.This
study
assessed
the
role
of
aryl
hydrocarbon
receptor
(AHR)
affinity,
and
cytochrome
P4501A
(CYP1A)
protein
and
activity
in
polyaromatic
hydrocarbon
(PAH)-‐induced
oxidative
stress.
In
the
1-‐100
nM
concentration
range
benzo[a]pyrene
(BaP)
but
not
benzo[e]pyrene
(BeP)
competitively
displaced
2
nM
[3H]2,
3,
7,
8-‐tetrachloro-‐dibenzo-‐p-‐dioxin
from
rainbow
trout
AHR2α.
Based
on
appearance
of
fluorescent
aromatic
compounds
in
bile
over
3,
7,
14,
28
or
50
days
of
feeding
3
μg
of
BaP
or
BeP/g
fish/day,
rainbow
trout
liver
readily
excreted
these
polyaromatic
hydrocarbons
(PAHs)
and
their
metabolites
at
near
steady
state
rates.
CYP1A
proteins
catalyzed
more
than
98%
of
ethoxyresorufin-‐O-‐deethylase
(EROD)
activity
in
rainbow
trout
hepatic
microsomes.
EROD
activity
of
hepatic
microsomes
initially
increased
and
then
decreased
to
control
activities
after
50
days
of
feeding
both
PAHs.
Immunohistochemistry
of
liver
confirmed
CYP1A
protein
increased
in
fish
fed
both
PAHs
after
3
days
and
remained
elevated
for
up
to
28
days.
Neither
BaP
nor
BeP
increased
hepatic
DNA
adduct
concentrations
at
any
time
up
to
50
days
of
feeding
these
PAHs.
Comet
assays
of
blood
cells
demonstrated
marked
DNA
damage
after
14
days
of
feeding
both
PAHs
that
was
not
significant
after
50
days.
There
was
a
strong
positive
correlation
between
hepatic
EROD
activity
and
DNA
damage
in
blood
cells
over
time
for
both
PAHs.
Neither
CYP1A
protein
nor
3-‐
nitrotyrosine
(a
biomarker
for
oxidative
stress)
immunostaining
in
trunk
kidney
were
significantly
altered
by
BaP
or
BeP
after
3,
7,
14,
or
28
days.
There
was
no
clear
association
between
AHR2α
affinity
and
BaP
and
BeP-‐induced
oxidative
stress.The
Oregon
Agricultural
Experiment
Station,
Northwest
Fisheries
Science
Center,
and
RO1ES006272
from
the
National
Institute
of
Health
supported
this
work
Sablefish (Anoplopoma fimbra Pallas, 1814) plasma biochemistry and hematology reference intervals including blood cell morphology.
Plasma biochemistry and hematology reference intervals are integral health assessment tools in all medical fields, including aquatic animal health. As sablefish (Anoplopoma fimbria) are becoming aquaculturally and economically more important, this manuscript provides essential reference intervals (RI) for their plasma biochemistry and hematology along with reference photomicrographs of blood cells in healthy, fasted sablefish. Blood cell morphology can differ between fish species. In addition, blood cell counts and blood chemistry can vary between fish species, demographics, water conditions, seasons, diets, and culture systems, which precludes the use of RI's from other fish species. For this study, blood was collected for plasma biochemistry and hematology analysis between June 20 and July 18, 2019, from healthy, yearling sablefish, hatched and reared in captivity on a commercial diet. Overnight fast of 16-18 hours did not sufficiently reduce lipids in the blood, which led to visible lipemia and frequent rupture of blood cells during analysis. Therefore, sablefish should be fasted for 24 to 36 hours before blood is collected to reduce hematology artifacts or possible reagent interference in plasma biochemistry analysis. Lymphocytes were the most dominant leukocytes (98%), while eosinophils were rare, and basophils were not detected in sablefish. Neutrophils were very large cells with Döhle bodies. In mammals and avian species, Döhle bodies are usually signs of toxic change from inflammation, but no such association was found in these fish. In conclusion, lipemia can interfere with sablefish blood analysis, and available removal methods should be evaluated as fasting for up to 36 h might not always be feasible. Also, more studies are required to establish RI for different developmental stages and rearing conditions
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Transcriptional changes in innate immunity genes in head kidneys from Aeromonas salmonicida-challenged rainbow trout fed a mixture of polycyclic aromatic hydrocarbons
We previously observed that exposure to a complex mixture of high molecular weight polycyclic aromatic hydrocarbons (PAHs) increased sensitivity of rainbow trout (Oncorhynchus mykiss) to subsequent challenge with Aeromonas salmonicida, the causative agent of furunculosis. In this study, we evaluate potential mechanisms associated with disease susceptibility from combined environmental factors of dietary PAH exposure and pathogen challenge. Rainbow trout were fed a mixture of ten high molecular weight PAHs at an environmentally relevant concentration (7.82μg PAH mixture/g fish/day) or control diet for 50 days. After 50 days of PAH exposure, fish were challenged with either Aeromonas salmonicida at a lethal concentration 30 (LC30) or growth media without the pathogen (mock challenge). Head kidneys were collected 2, 4, 10 and 20 days after challenge and gene expression (q<0.05) was evaluated among treatments. In animals fed the PAH contaminated diet, we observed down-regulation of expression for innate immune system genes in pathways (p<0.05) for the terminal steps of the complement cascade (complement component C6) and other bacteriolytic processes (lysozyme type II) potentially underlying increased disease susceptibility after pathogen challenge. Increased expression of genes associated with hemorrhage/tissue remodeling/inflammation pathways (p<0.05) was likely related to more severe head kidney damage due to infection in PAH-fed compared to control-fed fish. This study is the first to evaluate transcriptional signatures associated with the impact of chronic exposure to an environmentally relevant mixture of PAHs in disease susceptibility and immunity
Assimilation Efficiency of PBDE Congeners in Chinook Salmon
Polybrominated
diphenyl ether (PBDE) flame retardants are environmental
contaminants that can accumulate in biota. PBDE accumulation in an
organism depends on exposure, assimilation efficiency, and elimination/metabolism.
Net assimilation efficiency represents the fraction of the contaminant
that is retained in the organism after exposure. In the present study,
congener-specific estimates of net PBDE assimilation efficiencies
were calculated from dietary exposures of juvenile Chinook salmon.
The fish were exposed to one to eight PBDE congeners up to 1500 ng
total PBDEs/g food. Mean assimilation efficiencies varied from 0.32
to 0.50 for BDE congeners 28, 47, 99, 100, 153, and 154. The assimilation
efficiency of BDE49 was significantly greater than 100%, suggesting
biotransformation from higher brominated congeners. Whole body concentrations
of BDE49 significantly increased with both exposure to increasing
concentrations of BDE99 and decreasing fish lipid levels, implying
lipid-influenced debromination of BDE99 to BDE49. Excluding BDE49,
PBDE assimilation efficiency was not significantly related to the
numbers of congeners in the diets, or congener hydrophobicity, but
was greater in foods with higher lipid levels. Estimates of PBDE assimilation
efficiency can be used in bioaccumulation models to assess threats
from PBDE exposure to Chinook salmon health and recovery efforts,
as well as to their predators