First report of Streptococcus parauberis in a cultured freshwater ornamental fish, the ram cichlid Mikrogeophagus ramirezi (Myers & Harry, 1948)

First paragraph: Since the first report of an outbreak of a streptococcal infection in rainbow trout (Oncorhynchus mykiss) in Japan in 1958 (Hoshina, Sano, & Morimoto,1958), streptococcosis has been responsible for significant mortalities resulting in considerable losses to the aquaculture industry (Noga,2010; Salati,2006). Numerous species from the family Streptococcaceae have been identified as aetiological agents of streptococcosis in fish (Noga,2010; Salati,2006; Toranzo, Magariños, & Romalde,2005), susceptibility to which was documented in both food (Inglis, Roberts, & Bromage,1993) and ornamental fish species (Russo, Mitchell, & Yanong,2006).Streptococcus parauberisis a coccoid, non-motile, alpha-haemolytic Gram-positive bacterium belonging to theStreptococcaceafamily (Nho etal.,2011) and has been reported as the aetiological agent of streptococcosis in a few fish species, including turbot (Scophthalmus maximus), olive flounder (Paralichthys olivaceus), sea bass (Sebastes ventricosus) and striped bass (Morone saxatilis) (Baeck, Kim, Gomez, & Park,2006; Domeénech etal.,1996; Haines etal.,2013; Mata etal.,2004; Oguro etal.,2014; Park etal.,2009).Streptococcus parauberishas been previously identified as the aetiological agent of bovine mastitis (Bradley,2002). It was formerly known asStreptococcustype II until comparative analysis of the sequence data ofStreptococcus uberistypes I and II showed that both were phylogenetically distinct, and the new speciesS.parauberiswas proposed (Williams and Collins1990)

The effect of tertiary treated wastewater on fish growth and health: Laboratory-scale experiment with Poecilia reticulata (guppy)

Treated wastewater (TWW) constitutes a sustainable water resource and has been used for fish culture in some countries around the world, although there are no comprehensive data on the effect of TWW on fish growth and health in the context of aquaculture production. Our objectives were to examine how fish culture in TWW affected fish growth and fitness, as well as compliance with the international standards for safe consumption. Guppy (Poecilia reticulata) fingerlings were reared in 0%, 50% and 100% tertiary TWW (TTWW), from the age of five days, for a period of four months. In water analyses, 33 out of 67 tested organic micropollutants (OMPs) were detected in the TTWW samples at least once, at concentrations that are typically reported in domestic TTWW. Fish survival ranged between 77-80% and did not differ between treatment groups. Fish growth and mortality following challenge infection with Tetrahymena sp. (which ranged between 64-68%), were similar among treatment groups. Of tested immunological parameters, lysozyme and anti-protease was similar among treatments while complement activity was highest in the 50% TTWW-reared fish. No abnormalities were observed in the histopathological analysis. Levels of heavy metals, poly-chlorinated-biphenyls (PCBs) and organochlorines (OCs) in fish were below the detection limit and below the Food and Agriculture Organization of the United Nations (FAO) and the European Union EU maximal permitted levels in food fish. Results suggest that the yield of fish grown in TTWW is potentially similar to that in freshwater, and the produced fish comply with the standards of consumer safety. The results are in line with previous studies that examined the feasibility of TWW-fed aquaculture.Jewish Charitable Association (ICA); Israel Ministry of Science and Technology [3-12876]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Pathogenic characteristics of Aeromonas veronii isolated from the liver of a diseased guppy (Poecilia reticulata)

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The Development of a Small-scale Laboratory System to Study Cryptocaryon irritans Infection in Seawater-adapted Guppies, Poecilia reticulata

The protozoan parasite Cryptocaryon irritans is responsible for significant economic losses of commercially farmed marine fishes. In this study we report, for the first time, C. irritans infection in the seawater-adapted guppy Poecilia reticulata. We describe a simple method for experimental propagation and maintenance of the infection in a laboratory, without apparent loss of infectivity, for 15 months. Fish were gradually adapted to increasing concentrations of artificial seawater by successive transfer to incremental steps of 10 ppt every 2 days and then transferred to disease propagation aquaria (salinity 30 ± 2 ppt) where the infection was maintained. Between 2- 3 fish were held at any one time in each aquaria, each fish being replaced once it succumbed to the infection and died. Gross observations of heavily infected fish revealed a uniform distribution of trophonts visible on the skin and fins as white surface lesions or ‘spots’ after 4-5 days. Death of the host usually occurred after 7-8 days. Heavily infected fish were fixed and processed using routine histological techniques and histological examination revealed infective trophonts, round or pyriform in shape, invading the fish epithelium as well as larger, feeding trophonts located beneath the epithelium. A thickening of the epithelial layers and a proliferation of mucous secreting cells was evident around embedded parasites

Efficacy of garlic based treatments against monogenean parasites infecting the guppy (Poecilia reticulata (Peters))

Monogenean infections of commercially farmed fishes are responsible for significant economic losses. Garlic (Allium sativum) is a well-known spice which also possesses anti-microbial and anti-parasitical properties. The current work aimed to test the efficacy of garlic-based treatments against infection with monogenean sp. in the guppy (Poecilia reticulata). Clipped sections of tail fins of guppies heavily infected withGyrodactylus turnbulliwere exposed to aqueous garlic extract (7.5 to 30mLL−1) and visually observed under a dissecting microscope. Results revealed that exposure to garlic caused detachment of parasite and cessation of movement indicating death. A positive correlation was seen between garlic concentration and time to detachment and death of parasites, which, at the highest concentration of 30mLL−1, occurred at 4.1 and 8.6min, respectively. Bathing in aqueous garlic extract (7.5 and 12.5mLL−1) was tested in guppies infected withG. turnbulli. Prior acute toxicity tests revealed the maximum tolerance levels of guppies to garlic extract to be 12.5mLL−1for 1h. Bathing of infected fish in garlic extract (7.5 and 12.5mLL−1) significantly (p<0.05) reduced infection prevalence and intensity as compared to the control. Oral treatments using dry garlic powder-supplemented diet were tested on guppies infected withG. turnbulliandDactylogyrussp. Fish were fed with food containing 10% and 20% dry garlic powder for 14 days. Groups fed with garlic supplemented diets showed significantly reduced (p<0.05) mean prevalence and mean intensity of parasites as compared to the control. Dietary application of garlic did not appear to affect palatability. Fresh crushed garlic was added at a level of 1gL−1and applied as an indefinite bath for 14 days. This treatment was seen to significantly reduce (p<0.05) parasite prevalence and mean intensity as compared to the control. Histopathology revealed elevated muscular dystrophy in the 20% garlic-fed group, as compared to control. These findings demonstrate the potential of garlic as a natural alternative to currently used chemical treatments formonogeneansp. infection in the guppy

A novel treatment against the monogenean parasite, Gyrodactylus turnbulii, infecting guppies (Poecilia reticulata), using a plant-based commercial insecticide Timor C

Monogenean infections are a common cause of fish morbidity and mortality in aquaculture. In most cases, treatment relies on the application of toxic or unapproved chemicals. Therefore, alternative treatments against monogenean infections in fish that are safe and environmentally friendly are needed. In the present study, the efficiency of Timor C, a plant-based commercial insecticide, was investigated against Gyrodactylus turnbulii, a monogenean parasite infecting guppies (Poecilia reticulata). Since G. turnbulii primarily infects the fins and skin, with a predilection for the caudal fin, tail clips of heavily parasitized guppies were exposed in vitro to Timor C at various concentrations and parasite detachment and death were recorded over time. There was a positive correlation between time to detachment and Timor C concentration, with complete detachment within 60 min of exposure at a concentration of 50 ppm. Withdrawal of Timor C afterward did not lead to recovery of the exposed parasites. Treatment of infected fish for 24 h at 10 and 20 ppm was effective in lab-based trials, reducing the infection prevalence from 100% at time 0 to 22% post-treatment, and the infection rate to an average of less than one parasite per fish, as compared to an average of about five parasites per fish in the control. Repeated weekly treatment application for three consecutive weeks appeared safe for the fish, and did not cause an adverse effect to the biofiltration system, as determined by examining nitrification activity, compared to non-treated controls. Treatment was successfully tested in three separate applications at a commercial closed recirculating guppy farm, where a significant reduction in infection rates was achieved. Timor C was not toxic to Artemia at concentrations ranging from 10 to 100 ppm over 24 h of exposure. This study demonstrates the effectiveness of Timor C as a treatment against G. turnbulii infection in guppies and potentially against similar parasites in other aquacultural species

A novel treatment against the monogenean parasite, Gyrodactylus turnbulii, infecting guppies (Poecilia reticulata), using a plant-based commercial insecticide Timor C

Monogenean infections are a common cause of fish morbidity and mortality in aquaculture. In most cases, treatment relies on the application of toxic or unapproved chemicals. Therefore, alternative treatments against monogenean infections in fish that are safe and environmentally friendly are needed. In the present study, the efficiency of Timor C, a plant-based commercial insecticide, was investigated against Gyrodactylus turnbulii, a monogenean parasite infecting guppies (Poecilia reticulata). Since G. turnbulii primarily infects the fins and skin, with a predilection for the caudal fin, tail clips of heavily parasitized guppies were exposed in vitro to Timor C at various concentrations and parasite detachment and death were recorded over time. There was a positive correlation between time to detachment and Timor C concentration, with complete detachment within 60 min of exposure at a concentration of 50 ppm. Withdrawal of Timor C afterward did not lead to recovery of the exposed parasites. Treatment of infected fish for 24 h at 10 and 20 ppm was effective in lab-based trials, reducing the infection prevalence from 100% at time 0 to 22% post-treatment, and the infection rate to an average of less than one parasite per fish, as compared to an average of about five parasites per fish in the control. Repeated weekly treatment application for three consecutive weeks appeared safe for the fish, and did not cause an adverse effect to the biofiltration system, as determined by examining nitrification activity, compared to non-treated controls. Treatment was successfully tested in three separate applications at a commercial closed recirculating guppy farm, where a significant reduction in infection rates was achieved. Timor C was not toxic to Artemia at concentrations ranging from 10 to 100 ppm over 24 h of exposure. This study demonstrates the effectiveness of Timor C as a treatment against G. turnbulii infection in guppies and potentially against similar parasites in other aquacultural species

Efficacy of ginger-based treatments against infection with Gyrodactylus turnbulli in the guppy (Poecilia reticulata (Peters))

Monogenean infections of commercially farmed fishes are responsible for significant economic losses and existing chemical therapeutants, often stressful to the fish, pose associated risks. As part of a recent trend to move towards the use of alternative, plant-based remedies for commonly occurring aquaculture-related diseases, the efficiency of ginger (Zingiber officinale) was investigated against the monogenean parasite Gyrodactylus turnbulli in the guppy.In vitro trials revealed the clear anti-parasitic effects of ginger. Ethanolic and aqueous extracts, prepared from freeze dried ginger, were tested. An increase in extract concentration was associated with reduced time to parasite immobilisation, with ethanolic extract being more efficient; at 75 and 200 ppt aqueous ginger extract parasites died at 65.6±2.8 and 1.8±0.2min, respectively, whereas at 5 and 40 ppt ethanolic extract parasites died at 26.1±0.7 and 4.9±0.3min, respectively.  Bathing G. turnbulli-infected fish in ethanolic ginger extract (i.e. 5 and 7.5 ppt for 90 and 30 min, respectively) significantly reduced infection prevalence and intensity when compared to the water and ethanol controls. The higher concentration (i.e.7.5 ppt) proved as equally effective as Praziquantel, the conventionally used chemical treatment for gyrodactylosis, with the fish appearing to be completely cleared of the infection in both cases. Oral treatments of G. turnbulli-infected guppies with diets supplemented with 10 and 20% ginger powder proved to be ineffective in decreasing parasite load. These findings demonstrate that immersion in ginger extract offers an effective, alternative treatment against monogenean infection in fish

Dietary Supplementation With ω6 LC-PUFA-Rich Algae Modulates Zebrafish Immune Function and Improves Resistance to Streptococcal Infection

Arachidonic acid (ARA, 20:4n-6) and dihomo-γ-linolenic acid (DGLA, 20:3n-6) are omega-6 long-chain polyunsaturated fatty acids (LC-PUFA), which are key precursors for lipid mediators of the immune system and inflammatory response. The microalga Lobosphaera incisa (WT) and its Δ5-desaturase mutant P127 (MUT) are unique photosynthetic sources for ARA and DGLA, respectively. This study explores the effect of dietary supplementation with L. incisa and P127 biomass on tissue fatty acid composition, immune function, and disease resistance in zebrafish (Danio rerio). The broken microalgal biomass was added to commercial fish feed at 7.5 and 15% (w/w), providing 21.8 mg/g feed ARA for the WT-supplemented group and 13.6 mg/g feed DGLA for the MUT-supplemented group at the 15% inclusion levels. An unsupplemented group was used as the control. After 1 month of feeding, fish were challenged with Streptococcus iniae. Fish were sampled before the challenge and 1 week after the challenge for various analyses. Tissue ARA and DGLA levels significantly increased in the liver, corresponding to microalgal supplementation levels. The elevated expression of specific immune-related genes was evident in the kidneys in all treatment groups after 1 month of feeding, including genes related to eicosanoid synthesis, lysozyme, and NF-κB. In the liver, microalgal supplementation led to the upregulation of genes related to immune function and antioxidant defense while the expression of examined genes involved in ARA metabolism was downregulated. Importantly, fish fed with 15% of both WT- and MUT-supplemented feed showed significantly (p < 0.05) higher survival percentages (78 and 68%, respectively, as compared to only 46% in the control group). The elevated expression of genes related to inflammatory and immune responses was evident post-challenge. Collectively, the results of the current study demonstrate the potential of microalgae-derived dietary ARA and DGLA in improving immune competence and resistance to bacterial infection in zebrafish as a model organism