Placemat and rotational culturing: A novel method to control Cryptocaryon irritans infection by removing tomonts

Jiang, Biao; Li, Y.W.; Abdullahi, A. Y.; Dan, Xue-Ming; Gong, Hui; Ke, Qiaozhen; Li, A.X.; Li, G.Q.

doi:10.1016/j.aquaculture.2016.03.028

Cited by 31 publications

(7 citation statements)

References 23 publications

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“…Regularly changing aquaculture tanks would isolate the fish from the pathogens (8), but this practice is stressful for the fish. Regularly replacing the bottom place mat would be somewhat effective (9), but the associated labor costs could be exceedingly high. For these reasons, it would be a significant step forward in aquaculture management if the protomonts and tomonts could be killed using a nonpolluting and cost-effective method.…”

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confidence: 99%

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Yin

Bao

Liu

et al. 2019

Appl Environ Microbiol

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Copper and alloys containing >60% copper by weight are antimicrobial. In aquaculture, copper alloys are used as part of corrosion-resistant cages or as part of copper coating. To test whether a copper alloy surface prevents the outbreak of parasitosis in the aquaculture of Larimichthys crocea, we covered the bottom of the aquaculture tank with sheets of copper alloy containing 74% to 78% copper, and we cultured L. crocea juveniles that had been artificially infected with the protozoan parasite Cryptocaryon irritans. Our results showed that these copper alloy sheets effectively blocked the infectious cycle of C. irritans within a 1-week period and significantly reduced the number of C. irritans trophonts and tomonts, thereby decreasing the mortality rate of L. crocea. In in vitro assays, the cytoplasmic membranes of protomonts disintegrated and the cytoplasm overflowed after just 5 minutes of contact with copper alloy surfaces. Although the same cytoplasmic membrane disintegration was not observed in tomonts, the tomonts completely lost their capacity for proliferation and eventually died following direct contact with copper alloy sheets for 1 h; this is likely because C. irritans tomonts took in >100 times more copper ions following contact with the copper alloy sheets than within the control aquaculture environment. Exposure to copper alloy sheets did not lead to excessive heavy metal levels in the aquacultured fish or in the culture seawater. IMPORTANCE Cryptocaryon irritans, a parasitic ciliate that penetrates the epithelium of the gills, skin, and fins of marine fish, causes acute suffocation and death in cultured fish within days of infection. Much of the existing research centers around the prevention of C. irritans infection, but no cure has been found. Studies demonstrate that copper has strong antimicrobial properties, and fish grown in copper-containing cages have lower rates of C. irritans infection, compared to those grown in other currently used aquaculture cages. In this study, we found that an alloy containing 74% to 78% copper by weight effectively killed C. irritans cells and prevented cryptocaryoniasis outbreaks within a 1-week period. These findings offer a new perspective on the prevention and control of cryptocaryoniasis.

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confidence: 99%

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Yin

Bao

Liu

et al. 2019

Appl Environ Microbiol

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“…The infection intensity and damage degree of fish was positively associated with the number of theronts (Zhong et al, 2020). Hence, it is crucial to inactivate theronts to control the C. irritans infection in the aquaculture system (Jiang et al, 2016). The •OH inactivation threshold of C. irritans theronts was 1.0 mg∙min/L, which was 1/8 that of ClO 2 and 1/600 that of HCHO.…”

Section: Discussionmentioning

confidence: 99%

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO₂ or HCHO: Survival, physiological and histological response

Zhong

Bai

et al. 2022

Journal of Fish Diseases

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Cryptocaryon irritans causes one of the most serious diseases in various wild and cultured marine fish, leading to mass mortality and economic loss. In this study, hydroxyl radical (•OH) solution produced by strong ionization discharge combined with water jet cavitation effect was injected into orange-spotted grouper (Epinephelus coioides) aquaculture tanks for C. irritans control. The results showed that all C. irritans theronts were inactivated by •OH solution at concentrations of 0.5 mg/L within 2 min. •OH could induce alteration of shape, the absence of motility and macronucleus dispersion in theronts. A possible explanation was that the macronucleus of C. irritans might be damaged by •OH; as a result, its metabolism and life activities were disturbed. The •OH treatment increased the survival rate of E. coioides challenged with C. irritans from 64.7 ± 8.0% (mean ± SD) to 100% and reduced their infection intensity significantly. Stress response biomarkers such as malonaldehyde, glutathione, glutathione peroxidase, superoxide dismutase (SOD) and catalase levels in the gills of E. coioides at different time points were analysed. The SOD activity in the •OH group first decreased and then recovered to the initial level at the end of the experiment. The other stress response biomarkers had no significant difference from that in the uninfected control group after •OH treatment. Additionally, the gill of E. coioides in the •OH group exhibited slight and reversible transformation compared with the uninfected control group. Compared with •OH treatment, chlorine dioxide and formalin treatment reduced the survival rate, induced oxidative damage and changed the histological gill structure in E. coioides. In conclusion, •OH could be applied effectively to control C. irritans infection without affecting the normal physiological condition of E. coioides.

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“…T. blochii, which was more susceptible to C. irritans infections, were transferred across the net-pen cages, while B. taipingensis was added during the sampling period. This is a common practice adopted by farmers in Hong Kong and China to help reduce infections (moving fish around may have a "dilution" factor on infections) caused by parasites and other pathogens [34]. In this site, severe mortalities of juvenile T. blochii caused by C. irritans were reported by the farmer and diagnostics confirmed through the ambulatory of veterinary services of the Jockey Club College of Veterinary Medicine and Life Sciences from City University of Hong Kong (Figure 1a).…”

Section: Farm Selection Fish Species and Parasite Identificationmentioning

confidence: 99%

Digital Droplet PCR-Based Environmental DNA Tool for Monitoring Cryptocaryon irritans in a Marine Fish Farm from Hong Kong

et al. 2021

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The adoption of new investigative strategies based on environmental DNA (eDNA) can be used to monitor parasites, associated bacterial microbiomes, and physical-chemical parameters in fish farms. In this study, we used the economically important and globally distributed fish ciliate parasite Cryptocaryon irritans as a model to understand the parasite abundance and potential drivers of its presence in marine fish farms. Environmental (rainfall) and physical-chemical (temperature, oxygen, salinity, pH) data collected from a marine fish farm in Hong Kong were analyzed together with the eDNA approach targeting C. irritans abundance based on digital droplet PCR and 16S metagenomics to determine associations and triggers between parasites and specific bacterial groups. Rainfall and temperature demonstrated positive associations with high abundance of C. irritans (eDNA) at the studied marine fish cage farm. However, rainfall was the only parameter tested that demonstrated a significant association with parasite eDNA, indicating that the raining season is a risky period for fish farmers in Hong Kong. Coraliomargarita was the bacterial genus with the most significant relationship with low abundance of C. irritans in water. Understanding the environmental triggers of ciliate parasites propagation and associated bacterial microbiome could elucidate new insights into environmental control, microbial management, and promote the reduction of chemical use in marine fish farms.

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Placemat and rotational culturing: A novel method to control Cryptocaryon irritans infection by removing tomonts

Cited by 31 publications

References 23 publications

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO₂ or HCHO: Survival, physiological and histological response

Digital Droplet PCR-Based Environmental DNA Tool for Monitoring Cryptocaryon irritans in a Marine Fish Farm from Hong Kong

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Placemat and rotational culturing: A novel method to control Cryptocaryon irritans infection by removing tomonts

Cited by 31 publications

References 23 publications

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO2 or HCHO: Survival, physiological and histological response

Digital Droplet PCR-Based Environmental DNA Tool for Monitoring Cryptocaryon irritans in a Marine Fish Farm from Hong Kong

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Product

Resources

About

Treatments of orange‐spotted grouper (Epinephelus coioides) against Cryptocaryon irritans with •OH, ClO₂ or HCHO: Survival, physiological and histological response