scholarly journals Gnotobiotic rainbow trout (Oncorhynchus mykiss) model reveals endogenous bacteria that protect against Flavobacterium columnare infection

2021 ◽  
Vol 17 (1) ◽  
pp. e1009302
Author(s):  
David Pérez-Pascual ◽  
Sol Vendrell-Fernández ◽  
Bianca Audrain ◽  
Joaquín Bernal-Bayard ◽  
Rafael Patiño-Navarrete ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Antibiotic Use ◽  
Control Fish ◽  
Economic Losses ◽  
Flavobacterium Columnare ◽  
Bacterial Strains ◽  
Farmed Fish ◽  
Germ Free ◽  
Significant Difference

The health and environmental risks associated with antibiotic use in aquaculture have promoted bacterial probiotics as an alternative approach to control fish infections in vulnerable larval and juvenile stages. However, evidence-based identification of probiotics is often hindered by the complexity of bacteria-host interactions and host variability in microbiologically uncontrolled conditions. While these difficulties can be partially resolved using gnotobiotic models harboring no or reduced microbiota, most host-microbe interaction studies are carried out in animal models with little relevance for fish farming. Here we studied host-microbiota-pathogen interactions in a germ-free and gnotobiotic model of rainbow trout (Oncorhynchus mykiss), one of the most widely cultured salmonids. We demonstrated that germ-free larvae raised in sterile conditions displayed no significant difference in growth after 35 days compared to conventionally-raised larvae, but were extremely sensitive to infection by Flavobacterium columnare, a common freshwater fish pathogen causing major economic losses worldwide. Furthermore, re-conventionalization with 11 culturable species from the conventional trout microbiota conferred resistance to F. columnare infection. Using mono-re-conventionalized germ-free trout, we identified that this protection is determined by a commensal Flavobacterium strain displaying antibacterial activity against F. columnare. Finally, we demonstrated that use of gnotobiotic trout is a suitable approach for the identification of both endogenous and exogenous probiotic bacterial strains protecting teleostean hosts against F. columnare. This study therefore establishes an ecologically-relevant gnotobiotic model for the study of host-pathogen interactions and colonization resistance in farmed fish.

scholarly journals Gnotobiotic rainbow trout (Oncorhynchus mykiss) model reveals endogenous bacteria that protect against Flavobacterium columnare infection

2020 ◽  
Author(s):  
David Pérez-Pascual ◽  
Sol Vendrell-Fernández ◽  
Bianca Audrain ◽  
Joaquín Bernal-Bayard ◽  
Rafael Patiño-Navarrete ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Fish Farming ◽  
Antibiotic Use ◽  
Control Fish ◽  
Economic Losses ◽  
Flavobacterium Columnare ◽  
Bacterial Strains ◽  
Germ Free ◽  
Significant Difference

ABSTRACTThe health and environmental risks associated with antibiotic use in aquaculture have promoted bacterial probiotics as an alternative approach to control fish infections in vulnerable larval and juvenile stages. However, evidence-based identification of probiotics is often hindered by the complexity of bacteria-host interactions and host variability in microbiologically uncontrolled conditions. While these difficulties can be partially resolved using gnotobiotic models harboring no or reduced microbiota, most host-microbe interaction studies are carried out in animal models with little relevance for fish farming. Here we studied host-microbiota-pathogen interactions in a germ-free and gnotobiotic model of rainbow trout (Oncorhynchus mykiss), one of the most widely cultured salmonids. We demonstrated that germ-free larvae raised in sterile conditions displayed no significant difference in growth after 35 days compared to conventionally-raised larvae, but were extremely sensitive to infection by Flavobacterium columnare, a common freshwater fish pathogen causing major economic losses worldwide. Furthermore, re-conventionalization with 11 culturable species from the conventional trout microbiota conferred resistance to F. columnare infection. Using mono-re-conventionalized germ-free trout, we identified that this protection is determined by a commensal Flavobacterium strain displaying antibacterial activity against F. columnare. Finally, we demonstrated that use of gnotobiotic trout is a suitable approach for the systematic identification of both endogenous and exogenous probiotic bacterial strains that may protect teleostean hosts against F. columnare and other pathogens. This study establishes a novel and ecologically-relevant gnotobiotic model that will improve the sustainability and health of aquaculture.

scholarly journals Multi-Approach Assessment for Stress Evaluation in Rainbow Trout Females, Oncorhynchus mykiss (Walbaum, 1792) from Three Different Farms during the Summer Season

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1810
Author(s):  
Paul Uiuiu ◽  
Călin Lațiu ◽  
Tudor Păpuc ◽  
Cristina Craioveanu ◽  
Andrada Ihuț ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Biochemical Parameters ◽  
Principal Component ◽  
Environmental Parameters ◽  
Blood Parameters ◽  
Summer Season ◽  
Farmed Fish ◽  
Blood Profile ◽  
Blood Biochemical

Blood biochemistry parameters are valuable tools for monitoring fish health. Their baseline values are still undefined for a multitude of farmed fish species. In this study, changes in the blood profile of rainbow trout females (Oncorhynchus mykiss) from three farms were investigated using different biomarkers during the summer season. In the given context, the main water physicochemical parameters were investigated and twelve biochemical parameters were measured from blood samples of rainbow trout reared in the Fiad, Șoimul de Jos, and Strâmba farms. We selected these farms because the genetic background of the rainbow trout is the same, with all studied specimens coming from the Fiad farm, which has an incubation station. Forty-five samples were collected monthly (May to August) throughout summer to observe the changes in the blood profile of rainbow trout. Principal component analysis showed a clear separation both among the studied farms and months. Furthermore, significant correlations (p < 0.05) between the majority of the biochemical parameters were found, indicating that the environmental parameters can influence several blood parameters at the same time. The present study provides several useful norms for assessing the welfare of rainbow trout, indicating that the relationships among different parameters are important factors in interpreting the blood biochemical profiles.

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.

The adrenergic volume changes of immature and mature rainbow trout (Oncorhynchus mykiss) erythrocytes

2000 ◽  
Vol 203 (19) ◽  
pp. 3025-3031 ◽  
Author(s):  
T. Lecklin ◽  
A. Tuominen ◽  
M. Nikinmaa
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Large Fraction ◽  
Control Fish ◽  
Volume Distribution ◽  
Volume Changes ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Before And After ◽  
Volume Response ◽  
Fluorescence Polarisation

In this study, we examined whether the adrenergic volume response of teleost erythrocytes is related to cell maturity. Rainbow trout (Oncorhynchus mykiss) were made anaemic by reducing their haematocrit to approximately 50 % of the original value. After 3–4 weeks, small, young erythrocytes were seen in the circulation. By measuring the volume distribution of blood samples from anaemic fish before and after noradrenaline stimulation (10 min, 10(−5)mol l(−1) final concentration), we were able to show that the volume response of young, immature erythrocytes to catecholamine stimulation was greater than that of mature erythrocytes. In addition, the membrane fluidity, measured using the steady-state fluorescence polarisation method, was greater in anaemic fish after 24 days of recovery from bleeding than in control fish. Since blood from anaemic fish contained a large fraction of immature erythrocytes, this result indicates that the fluidity of the membrane of immature erythrocytes is greater than that of mature erythrocytes.

scholarly journals Micronucleus occurrence in diploid and triploid rainbow trout (Oncorhynchus mykiss Walbaum)

2012 ◽  
Vol 48 (No. 8) ◽  
pp. 215-220 ◽  
Author(s):  
I. Strunjak-Perovic ◽  
R. Coz-Rakovac ◽  
N. Topic Popovic
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Water Temperature ◽  
Peripheral Circulation ◽  
Ploidy Levels ◽  
Mean Values ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Significant Difference

The aim of the study was to observe the influence of different ploidy levels in fish on micronucleus occur&shy;rence. Twenty minutes after fertilization, one group of rainbow trout eggs was exposed to water temperatures of 26&deg;C in duration of 20 minutes to induce triploidy. Second group was kept in water temperature of 10&deg;C, which is optimal for development of rainbow trout. The frequency of micronucleated erythrocytes was determined in the peripheral circulation of rainbow trout 67 days (following absorption of the yolk &ndash; swim-up stage) and 128 days (fry stage) post fertilization. There was a significant difference (P &lt; 0.001) between frequency of micronucleated erythrocytes of diploid (1.10 &plusmn; 0.96&permil;) and triploid (2.41 &plusmn; 1.28&permil;) fish at swim-up stage. Increased mean values of micronucleus in diploid (1.80 &plusmn; 1.57&permil;) and triploid (5.92 &plusmn; 3.80&permil;) fry were also recorded.

scholarly journals The Effect of Slaughtering Procedures on Blood Spotting in Rainbow Trout (Oncorhynchus Mykiss)

2011 ◽  
Vol 68 (2) ◽  
Author(s):  
George Liviu MIHALCA ◽  
Mihaela TIŢA ◽  
Ana MIHALCA ◽  
Ovidiu TIŢA
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Fish Muscle ◽  
Rigor Mortis ◽  
Visual Appearance ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Colour Measurements ◽  
Significant Difference

Rainbow trout (Oncorhynchus mykiss) was submitted for various slaughter and bleeding procedures to see what effect this would have on blood drainage of the muscles. Results show that the bleeding method is of less importance, while it is the timing that is important. No significant difference in bloodspotting was observed between fish that were bled live by a gill cut or percussive killed and bled by gutting. Most of the drainage of blood in the fish muscle seems to occur within the first hours postmortem, so rigor mortis is of little importance. The visual appearance of the fillet was influenced by number and size of the bloodstains. Colour measurements with Hunter L*, a*, b* did not reveal this. We conclude that a gill cut is not necessarily to obtain bleeding, so the industry can omit this phase and go directly to gutting.

scholarly journals Orally Administered Erythromycin in Rainbow Trout (Oncorhynchus mykiss): Residues in Edible Tissues and Withdrawal Time

2006 ◽  
Vol 51 (3) ◽  
pp. 1043-1047 ◽  
Author(s):  
Annarita Esposito ◽  
Laura Fabrizi ◽  
Dario Lucchetti ◽  
Luigi Marvasi ◽  
Ettore Coni ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Water Temperature ◽  
Fish Muscle ◽  
Feed Water ◽  
Farmed Fish ◽  
Withdrawal Time ◽  
Off Label ◽  
Intensive Farming ◽  
Council Directive

ABSTRACT Aquaculture production has notably increased in the last decades, mainly thanks to intensive farming. Together with market globalization, this gives rise to the spreading of several fish diseases, thus increasing the demand for veterinary drugs for aquatic species. Nonetheless, very few chemicals are registered for use in aquaculture, and fish farmers are often forced to resort to off-label use of drugs authorized for other food-producing animal species. Rainbow trout is the major farmed fish species in Italy and the second one in Europe. Erythromycin is the antibiotic of choice against gram-positive cocci, the major concern for trout farming, but it is not yet registered for aquaculture use in most European countries. The aim of this study was to follow the depletion of erythromycin in rainbow trout (Oncorhynchus mykiss), after its administration at 100 mg kg−1 trout body weight day−1 for 21 days through medicated feed (water temperature, 11.5°C). Erythromycin residues in fish muscle plus skin in natural proportion were determined by a validated liquid chromatography-electrospray ionization-tandem mass spectrometry method. Interpolation of our data, following European Agency for the Evaluation of Medicinal Products guidelines, gives a withdrawal time of 255°C-days (°C-day = water temperature × days), thus showing that the general value (500°C-day) recommended by the Council Directive (EEC) no. 82/2001 for off-label drug use in aquaculture would be too conservative in this case, with excessive costs for the farmers. Our study provides preliminary data for a more prudent use of erythromycin in rainbow trout, suggesting a possible withdrawal time after treatment.

Sign in / Sign up

Export Citation Format

Share Document