scholarly journals Chorion Alterations in Eyed-Stage Salmonid Eggs Farmed in La Araucanía, Chile: A Retrospective Study

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2427
Author(s):  
Iván Valdebenito ◽  
Elías Figueroa ◽  
Matías Valdebenito ◽  
Luis Paiva
Keyword(s):  
Rainbow Trout ◽  
Coho Salmon ◽  
Quality Analysis ◽  
Southern Chile ◽  
Fish Farms ◽  
Fish Embryo ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Abrupt Changes ◽  
Trout Farms ◽  
Salmonid Eggs

The chorion is the primary envelop that protects the fish embryo against mechanical actions, pathogens, and abrupt changes in physical and chemicals conditions of the incubation medium. During embryo development, chorion alterations are not rare, but the occurrence of these is scarcely reported. Increased frequency of chorion alterations can result in increased embryo mortality and thus decreased reproductive performance and losses for fish farms. In this study, we characterize different chorion alterations observed in samples collected over 14 years from 12 salmon and trout farms located in the region of La Araucanía in southern Chile, which sent live eyed-stage embryos (‘eyed-eggs’) for quality analysis to our laboratory. We found soft chorion as the most common alteration observed, being present in the whole 14-year series analyzed in Atlantic Salmon (Salmo salar) and affecting up to 35.0% of the samples examined in a year. This alteration also affected up to 20.0 and 5.7% of Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Oncorhynchus mykiss) samples analyzed in a year, respectively. We also found an increase of other chorion alterations, including perforated and white-spotted chorion in Atlantic and Coho Salmon, in the last 8 years. Among the three species, Rainbow Trout exhibited fewer chorion alterations. As the embryonated eggs analyzed here were obtained from broodstocks maintained under standard industrial conditions, these alterations might be linked to changes in environmental conditions affecting the incubation water that need to be further investigated.

scholarly journals Study of pathogenicity and severity of Lactococcus garvieae isolated from rainbow trout (Oncorhynchus mykiss) farms in Kohkilooieh and Boyerahmad province

2019 ◽  
Vol 22 (1) ◽  
Author(s):  
Esmaeil Karami ◽  
Mojtaba Alishahi ◽  
Taravat Molayemraftar ◽  
Masoud Ghorbanpour ◽  
Mohammad Reza Tabandeh ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Systemic Infection ◽  
Fish Farms ◽  
Pcr Assay ◽  
Biochemical Tests ◽  
High Severity ◽  
Lactococcus Garvieae ◽  
Specific Pcr ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Trout Farms

Abstract Background Lactococcus garvieae is one of the most important risk factors in the rainbow trout culture. Therefore, the purpose of this study was to identify and detect strains isolated from rainbow trout suspected of having Lactococcus garvieae using biochemical characteristics and PCR and determination of the degree of severity of isolated strains. Methods In this study, the cause of lactococcosis in selected rainbow trout farms in Kohkilooieh and Boyerahmad province was assayed. Gram-positive and catalase-negative bacterial isolates were first obtained from selected trout fish farms using conventional biochemical tests and PCR assay. The 10-day LD50 method (concentration causing 50% mortality in 10 days) was used to determine the severity of the isolated bacteria. Results One bacterial isolate was detected from all sampled fish which confirmed as Lactococcus garvieae using a specific PCR assay based on the 16S rDNA gene by producing a single band of 1107 bp. Analysis of the rate of mortality showed that the 10-day LD50 was 4.6 × 105 CFU/fish. The results of this study showed that isolated bacteria had high severity for rainbow trout. The presence of bacteria in internal organs of suspected fish showed a severe systemic infection in challenged fish. Antibiogram assay also indicated that the isolated Lactococcus garvieae were resistant to some mostly used antibiotics in rainbow trout. Conclusions According to current research, it can be concluded that the condition of lactococcosis in the studied area is not suitable, and despite the presence of disease, there is no proper action to control and prevent the disease. Unfortunately, isolated bacteria from the studied area have a very high severity compared to bacteria isolated from other regions of the country or other countries. Therefore, further investigation is needed to determine the cause of this difference and possibly in the design of the vaccine.

scholarly journals Weissellosis in rainbow trout in Colombia

2020 ◽  
Vol 13 (3) ◽  
pp. 575-580
Author(s):  
Gersson Vásquez-Machado ◽  
Miguel Rubiano-Garzón ◽  
Jonny Yepes-Blandón ◽  
Daniel Gordillo-González ◽  
Jersson Avila-Coy
Keyword(s):  
Rainbow Trout ◽  
Clinical Signs ◽  
Fish Swimming ◽  
Gram Positive Bacteria ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Ocular Lesions ◽  
Intraocular Hemorrhage ◽  
Trout Farms ◽  
Kidney Liver ◽  
Corneal Rupture

Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.

scholarly journals Chromosomal characterization of cultured populations of Chilean coho salmon (Oncorhynchus kistuch)

1999 ◽  
Vol 22 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Nelson Colihueque V.
Keyword(s):  
Pericentric Inversion ◽  
Chromosome Pair ◽  
Secondary Constriction ◽  
Coho Salmon ◽  
Southern Chile ◽  
Fish Farms ◽  
Submetacentric Chromosome ◽  
Chromosome Arm

Chromosomal characterization of coho salmon samples from three fish farms in southern Chile (Polcura, Castro and Coyhaique) was carried out in order to compare their chromosome constitutions. All populations had a 2n = 60; however, Polcura and Coyhaique had a different chromosome arm number (NF = 110; 40m + 10sm + 10st/t) than Castro (NF = 108; 40m + 8sm + 12st/t). Variation in NF was due to chromosome pair 25, which was submetacentric in Coyhaique and Polcura, but subtelocentric in Castro. In all karyotypes, a large submetacentric chromosome pair exhibited an interstitial secondary constriction in the short arm. The observed variability in chromosome arm number agrees with previous reports for O. kisutch, and in this particular case it seemed to be caused by a pericentric inversion of pair 25. Cultured populations of Chilean coho salmon are, therefore, likely to be cytogenetically variable.

scholarly journals Current bacterial diseases of fresh water fishes

2005 ◽  
Vol 21 (3-4) ◽  
pp. 141-151 ◽  
Author(s):  
Svetlana Jeremic ◽  
Vladimir Radosavljevic ◽  
Dobrila Jakic-Dimic
Keyword(s):  
Rainbow Trout ◽  
Culture Media ◽  
Clinical Manifestations ◽  
Fish Farming ◽  
Diagnostic Methods ◽  
Feed Conversion ◽  
Fish Farms ◽  
Bacterial Diseases ◽  
Fish Pathology ◽  
Trout Farms

From the beginning of fish cultivation, diseases have appeared as a serious problem in this branch of agriculture. In recent years, by the intensifying of production, fish diseases have become even more significant and complex field. Bacterial diseases are constant threat for fish farming, and because of rapid course and severity of clinical manifestations the represent significant part of fish pathology, and also have great economical importance. Harmful effects of bacterial diseases on fishes are: increased morbidity and mortality rate, decreased feed conversion efficiency, decreased growth rates, weakening of fishes, and reproduction problems. In order to examine epizootiological situation and occurrence of bacterial diseases among cultured fish in Serbia, three year research was carried out in 7 carp farms and 3 rainbow trout farms. Also, regular systematic examinations were conducted. Samples of internal organs, skin and gills were inoculated with streak-plate technique on standard and differential culture media plates. Inoculated plates were incubated for 24-48 hours at 20?C and 30?C. After incubation period, colonies were examined, and determination was done on the basis of following characteristics of colonies: form, color, mucosity granulation, roughness and hemolytic properties. Determination of bacterial isolates was done by using API 20E, API rapid. API Coryne systems, and by agglutination method with hyper immune aera. The most frequent diseases among the farmed carp and rainbow trout populations in the examined fish farms were: Bacterial gill disease, Columnaris disease. Yersiniosis Renibacteriosis, Erythrodermatitis. Motile Aeromonas and Pseudomonas infections. Based on the obtained results, modern diagnostic methods were implemented and proper prevention and successful therapy was taken.

Sign in / Sign up

Export Citation Format

Share Document