scholarly journals Impacts of salmon lice on mortality, marine migration distance and premature return in sea trout

2020 ◽  
Vol 635 ◽  
pp. 151-168 ◽  
Author(s):  
RM Serra-Llinares ◽  
T Bøhn ◽  
Ø Karlsen ◽  
R Nilsen ◽  
C Freitas ◽  
...  
Keyword(s):  
Fresh Water ◽  
Salmo Trutta ◽  
Statistical Power ◽  
Fork Length ◽  
Control Fish ◽  
Control Group ◽  
Salmon Lice ◽  
Artificial Infestation ◽  
Marine Migration ◽  
Feeding Resources

Brown trout Salmo trutta (L.) is a facultative anadromous species, where a portion of individuals in populations with access to the sea perform migrations to use the richer feeding resources. We investigated the effect of salmon lice Lepeophtheirus salmonis (Krøyer 1837) infestation on the survival and behaviour of wild trout post-smolts (average fork length = 180 mm) during their marine migration. Comparisons of the marine migratory behaviour were made between an artificially infested group (n = 74) and a control group (n = 71) in an area with low natural lice infestation pressure. Artificial infestation was estimated to cause 100% prevalence and a mean intensity of 65 lice fish-1 (mean relative intensity of 2.4 lice g-1 fish). Survival analysis showed limited statistical power but revealed lice-induced mortality, with an estimated hazard ratio of 2.73 (95% CI = 1.04-7.13) compared to the control group, when data from a previous pilot study were included. Surviving individuals in the infested group additionally responded by residing closer to fresh water while at sea, and by prematurely returning to fresh water. On average, infested fish returned to fresh water after only 18 d at sea, while control fish spent on average 100 d at sea. The residency in the inner part of the fjord and the premature return to fresh water represent an adaptive behavioural response to survive the infestation, at the probable cost of reduced growth opportunities and compromised future fitness.

scholarly journals Changes in intestinal microbiota and humoral immune response following probiotic administration in brown trout (Salmo trutta)

2007 ◽  
Vol 97 (3) ◽  
pp. 522-527 ◽  
Author(s):  
José Luis Balcázar ◽  
Ignacio de Blas ◽  
Imanol Ruiz-Zarzuela ◽  
Daniel Vendrell ◽  
Ana Cristina Calvo ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Humoral Response ◽  
Lysozyme Activity ◽  
Control Fish ◽  
Control Group ◽  
Humoral Immune ◽  
Colony Forming Units ◽  
Significant Difference ◽  
Brown Trout Salmo Trutta

We studied the effect of several lactic acid bacteria (LAB) on the humoral response of brown trout (Salmo trutta). LAB groups (Lactococcus(Lc.)lactisssp.lactis,Lactobacillus(Lb.)sakeiandLeuconostoc(Leu.)mesenteroides) were administered orally at 106colony-forming units/g feed to brown trout for 2 weeks, after which fish were switched to an unsupplemented feed. Blood and intestinal samples were taken from the onset of feeding supplemented diets at 1, 2, 3 and 4 weeks. During the LAB-feeding period,Lc. lactisssp.lactis,Lb. sakeiandLeu. mesenteroidespersisted in the fish intestines, but the number of LAB slowly decreased in the intestines after changing to the unsupplemented diet. OnlyLb. lactisssp.lactisandLeu. mesenteroideswere detected at levels above 1 × 102colony-forming units/g at the end of the fourth week. In comparison to untreated control fish, the alternative complement activity in the serum was found to be significantly greater in all LAB groups at the end of the second week. Groups supplemented withLc. lactisssp.lactisandLeu. mesenteroidesexhibited an elevated level of lysozyme activity at the end of the third week, but the group supplemented withLb. sakeidid not exhibit any significant change in lysozyme activity. Serum immunoglobulin levels were higher compared with the control group, but there was no significant difference between the LAB and control groups.

scholarly journals Effects of laboratory salmon louse infection on osmoregulation, growth and survival in Atlantic salmon

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Per Gunnar Fjelldal ◽  
Tom J Hansen ◽  
Ørjan Karlsen
Keyword(s):  
Atlantic Salmon ◽  
Infection Intensity ◽  
Infected Fish ◽  
Control Fish ◽  
Control Group ◽  
Threshold Values ◽  
Growth And Survival ◽  
Salmon Lice ◽  
Intensity Threshold ◽  
Specific Growth Rates

Abstract Anadromous Atlantic salmon (Salmo salar) rely on long ocean migrations to build energy stores for maturation and spawning. In seawater, wild Atlantic salmon are threatened by high salmon lice (Lepeophtheirus salmonis) infestation levels resulting from intensive salmonid sea-cage aquaculture. Salmon lice infection can cause a stress response and an osmotic imbalance in the host. The lice infection intensity threshold values for these responses, however, remain to be identified in Atlantic salmon. In order to define this under laboratory conditions, individually tagged F1 wild origin Atlantic post-smolts (40 g) were infected with salmon lice copepodids or left as uninfected controls. Twenty-eight days post infection, infected post-smolts had a mean of 0.38 (range of 0.07–0.9) mobile lice g−1 fish weight. During this period, specific growth rates (SGRs) were lower in infected than control fish (0.4 vs 1.0% day−1). Higher plasma Na+, Cl− and osmolality in infected fish also indicate osmoregulatory impairment. SGR correlated negatively with plasma Na+, Cl−, osmolality and cortisol in the infected, but not in the control group. Infection intensity (lice g−1 fish) correlated positively with mortality rate and plasma Na+, Cl−, osmolality and cortisol and correlated negatively with SGR and condition factor. Calculated lice intensity threshold values for changes in plasma ions were 0.18 lice g−1 for plasma Cl−, and 0.22 lice g−1 for plasma Na+. Moribund infected fish occurred at infection intensities above 0.2 lice g−1, and these fish had extreme plasma Cl−, Na+, osmolality and cortisol levels. There was a positive correlation between plasma cortisol and plasma Na+, Cl− and osmolality in infected fish. This study provides vital information that can be used to define thresholds in the monitoring and conservation of wild Atlantic salmon populations affected by aquaculture-driven salmon lice infestations.

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome

2011 ◽  
Vol 14 (3) ◽  
pp. 443-448 ◽  
Author(s):  
N. Kurhalyuk ◽  
H. Tkachenko ◽  
K. Pałczyńska
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Thiobarbituric Acid Reactive Substance ◽  
Tbars Level ◽  
Reactive Substance ◽  
Brown Trout Salmo Trutta

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome In the present work we evaluated the effect of ulcerative dermal necrosis (UDN) syndrome on resistance of erythrocytes to haemolytic agents and lipid peroxidation level in the blood from brown trout (Salmo trutta m. trutta L.). Results showed that lipid peroxidation increased in erythrocytes, as evidenced by high thiobarbituric acid reactive substance (TBARS) levels. Compared to control group, the resistance of erythrocytes to haemolytic agents was significantly lower in UDN-positive fish. Besides, UDN increased the percent of hemolysated erythrocytes subjected to the hydrochloric acid, urea and hydrogen peroxide. Results showed that UDN led to an oxidative stress in erythrocytes able to induce enhanced lipid peroxidation level, as suggested by TBARS level and decrease of erythrocytes resistance to haemolytic agents.

scholarly journals Chimeric Protein IPath® with Chelating Activity Improves Atlantic Salmon’s Immunity against Infectious Diseases

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 361
Author(s):  
Valentina Valenzuela-Muñoz ◽  
Bárbara P. Benavente ◽  
Antonio Casuso ◽  
Yeny Leal ◽  
Cristian Gallardo-Escárate
Keyword(s):  
Immune Response ◽  
Atlantic Salmon ◽  
Iron Metabolism ◽  
Iron Transport ◽  
Aeromonas Salmonicida ◽  
Transcriptional Analysis ◽  
Control Fish ◽  
Control Group ◽  
Commercial Fish ◽  
Chelating Activity

Infection processes displayed by pathogens require the acquisition of essential inorganic nutrients and trace elements from the host to survive and proliferate. Without a doubt, iron is a crucial trace metal for all living organisms and also a pivotal component in the host–parasite interactions. In particular, the host reduces the iron available to face the infectious disease, increasing iron transport proteins’ expression and activating the heme synthesis and degradation pathways. Moreover, recent findings have suggested that iron metabolism modulation in fish promotes the immune response by reducing cellular iron toxicity. We hypothesized that recombinant proteins related to iron metabolism could modulate the fish’s immune system through iron metabolism and iron-responsive genes. Here a chimeric iron transport protein (IPath®) was bioinformatically designed and then expressed in a recombinant bacterial system. The IPath® protein showed a significant chelating activity under in vitro conditions and biological activity. Taking this evidence, a vaccine candidate based on IPath® was evaluated in Atlantic salmon challenged with three different fish pathogens. Experimental trials were conducted using two fish groups: one immunized with IPath® and another injected with adjutant as the control group. After 400 accumulated thermal units (ATUs), two different infection trials were performed. In the first one, fish were infected with the bacterium Aeromonas salmonicida, and in a second trial, fish were exposed to the ectoparasite Caligus rogercresseyi and subsequently infected with the intracellular bacterium Piscirickettsia salmonis. Fish immunized with IPath® showed a significant delay in the mortality curve in response to A. salmonicida and P. salmonis infections. However, no significant differences between infected and control fish groups were observed at the end of the experiment. Notably, sea lice burden reduction was observed in vaccinated Atlantic salmon. Transcriptional analysis evidenced a high modulation of iron-homeostasis-related genes in fish vaccinated with IPath® compared to the control group during the infection. Moreover, increasing expression of Atlantic salmon IgT was associated with IPath® immunization. This study provides evidence that the IPath® protein could be used as an antigen or booster in commercial fish vaccines, improving the immune response against relevant pathogens for salmon aquaculture.

scholarly journals Physical activity in the classroom to prevent childhood obesity: a pilot study in Santiago, Chile

2017 ◽  
Vol 6 ◽  
Author(s):  
Francisco Mardones ◽  
Pilar Arnaiz ◽  
Johana Soto-Sánchez ◽  
Juana Saavedra ◽  
Angélica Domínguez ◽  
...  
Keyword(s):  
Physical Activity ◽  
Blood Pressure ◽  
Pilot Study ◽  
Grip Strength ◽  
Statistical Power ◽  
Physical Activity Intervention ◽  
Hand Grip Strength ◽  
Control Group ◽  
High Waist Circumference ◽  
Hand Grip

AbstractThis paper describes a 4-month pilot study that tested the suitability of a physical activity intervention for first graders (children aged 6 and 7 years) in a public school in Santiago, Chile. Teachers were trained to deliver the programme in the classroom during the school day. Teachers were surveyed to determine if this intervention fit within their curriculum and classroom routines and they reported in a focus group that it was suitable for them. All children actively participated in the programme and positive changes in their attitudes towards physical activity were observed by their teachers. Anthropometrics, blood pressure and hand grip strength were measured in the students. A significant reduction was observed in children with high waist circumference ≥ 90th percentile, and in mean systolic blood pressure. However, statistical power values for those comparisons were rather low. Anthropometry and hand grip strength were not modified. The latter calculations and the lack of a control group are showing the weaknesses of this pilot study and that further research with a larger sample size and an experimental design is strongly needed.

Does reduced feeding prior to release improve the marine migration of hatchery brown trout Salmo trutta smolts?

2014 ◽  
Vol 85 (6) ◽  
pp. 1992-2002 ◽  
Author(s):  
J. G. Davidsen ◽  
M. Daverdin ◽  
A. D. Sjursen ◽  
L. Rønning ◽  
J. V. Arnekleiv ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Marine Migration ◽  
Brown Trout Salmo Trutta

School Progress and Cognitive Development of 6-Year-Old Children Whose Mothers Were Treated Antenatally with Betamethasone

PEDIATRICS ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 99-105 ◽  
Author(s):  
B. A. MacArthur ◽  
R. N. Howie ◽  
J. A. Dezoete ◽  
J. Elkins
Keyword(s):  
Cognitive Development ◽  
Statistical Power ◽  
Control Group ◽  
Psychometric Tests ◽  
Premature Labor ◽  
Second Year ◽  
School Progress

The cognitive development of children whose mothers had been included in the first Auckland trials of betamethasone therapy in premature labor were studied. An earlier study of these children used psychometric tests during the fifth year of life. In the present study tests were given during the seventh year of life (the second year of school) to 250 (82.2%) of 304 surviving children. Of the 250 children, 139 were in the group whose mothers had received betamethasone and 111 were in the control group. Further tests of cognitive development were made, together with assessment of the children's progress in school. Again, on the majority of measures there were no significant differences between children whose mothers had received betamethasone and the children in the control group. Calculations of statistical power showed that important differences were unlikely to have been missed.

scholarly journals Salmon lice evasion, susceptibility, retention, and development differ amongst host salmonid species

2017 ◽  
Vol 75 (3) ◽  
pp. 1071-1079 ◽  
Author(s):  
Samantha Bui ◽  
Elina Halttunen ◽  
Agnes M Mohn ◽  
Tone Vågseth ◽  
Frode Oppedal
Keyword(s):  
Atlantic Salmon ◽  
Chinook Salmon ◽  
Salmo Trutta ◽  
Parasite Development ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Salmon Lice ◽  
Salmonid Species ◽  
Host Parasite ◽  
Temporal Overlap

Abstract With different ecological characteristics amongst salmonid species, their response to parasitic infestation is likely to vary according to their spatial and temporal overlap with the parasite. This study investigated the host–parasite interactions amongst three species of salmonids and the ectoparasitic salmon louse, Lepeophtheirus salmonis. To determine any variation in infestation parameters amongst salmonids, single population groups of Atlantic salmon (Salmo salar), chinook salmon (Onchorhynchus tshawytscha), and previously-infested and naïve sea trout (Salmo trutta) were exposed to a controlled infestation challenge. We found that chinook salmon and both sea trout groups were more susceptible to acquiring lice than Atlantic salmon. Behavioural responses during infestation were more pronounced in Atlantic and chinook salmon. Parasite development was similar in lice attached to Atlantic salmon and sea trout, but hindered on chinook salmon. At 16 days post-infestation, chinook salmon had reduced lice loads to the same level as Atlantic salmon, whilst sea trout retained their lice. These results demonstrate differences in interactions with L. salmonis amongst these species, and highlight the vulnerability of sea trout to infestation.

scholarly journals Effects of salmon lice Lepeophtheirus salmonis on wild sea trout Salmo trutta—a literature review

2015 ◽  
Vol 7 (2) ◽  
pp. 91-113 ◽  
Author(s):  
EB Thorstad ◽  
CD Todd ◽  
I Uglem ◽  
PA Bjørn ◽  
PG Gargan ◽  
...  
Keyword(s):  
Literature Review ◽  
Salmo Trutta ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Salmon Lice

scholarly journals Immune Response of Rainbow Trout (Oncorhynchus mykiss) to Selected Antigens of Yersinia ruckeri

2009 ◽  
Vol 78 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Unal Ispir ◽  
H. Bayram Gokhan ◽  
Mikail Ozcan ◽  
Mustafa Dorucu ◽  
Naim Saglam
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Metabolic Activity ◽  
Control Fish ◽  
Phagocytic Index ◽  
Control Group ◽  
Yersinia Ruckeri ◽  
Whole Cells ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Fish Group

In this study, effects of Yersinia ruckeri antigens on the immune mechanisms of rainbow trout (Oncorhynchus mykiss) were examined. The weight of the 120 fish used in this study was 20–30 g. After injecting 1 mg of formalin-inactivated whole cells (FKC) and O-antigen (Ag-O) intraperitoneally, blood was taken from the caudal vein of anaesthetized fish and metabolic activity of leukocytes (Nitroblue tetrazolium (NBT) activities), phagocytic activity (PA), phagocytic index (PI), serum protein and serum total immunoglobulin (TIg) levels were determined on day 30 after the first immunization. The same procedure was conducted in the control group. In all the experimental groups, considerable increases in the immune indicators were found and significant differences detected between the control and experimental groups (p < 0.05). Metabolic activity of leukocytes decreased significantly (p < 0.05) during the following treatment with antigens compared to the control fish group.

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