Identification of an isolate of Saprolegnia ferax as the causal agent of saprolegniosis of Yellow catfish (Pelteobagrus fulvidraco) eggs

Cao, Haipeng; Zheng, Weidong; Xu, Jun; Ou, Renjian; He, Shan; Yang, Xianle

doi:10.1007/s11259-012-9536-8

Cited by 30 publications

(31 citation statements)

References 25 publications

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“…() to have useful antifungal activity; however, our results and those of Cao et al. () noted that Cnidium monnieri did not inhibit Saprolegnia sp. growth.…”

Section: Discussioncontrasting

confidence: 80%

“…Good efficacy on control of S. parasitica infection in grass carps was observed with copper sulfate (Sun et al., ); Cao et al. () also found that a concentration of dithiocyano‐methane, another compound used to treat saprolegniosis, can influence the zoospore number of Saprolegnia ferax . None of these therapeutants, however, overcome the issue of applying treatments to large ponds.…”

Section: Discussionmentioning

confidence: 99%

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The in vitro antifungal activity of 30 Chinese herb extracts to Saprolegnia sp.

et al. 2015

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Chinese traditional medicines have been used for several thousands of years in Asian countries, not only in humans but also in many animal species. These compounds prevent and control different types of diseases including internal diseases as well as some infectious diseases, where the aetiological agent is viral, bacterial, parasitic or mycotic. Rhizoma coptidis is believed to inhibit Shigella dysenteriae and that Radix isatidis can prevent flu caused by the influenza virus. It is thus hypothesized that some of these traditional herbal compounds will have anti-fungal activity. Saprolegniosis is a disease common in fish and their eggs in both fresh and brackish water; a newer, safer medication against Saprolegnia is needed after the prohibition in many countries of the extremely effective fungicide, malachite green. In the present study an attempt is made to identify herbal compounds that have anti-Saprolegnia activity. A strain of Saprolegnia, CCF1301, was isolated from the skin of infected grass carp (Ctenopharyngodon idella) and identified as Saprolegnia ferax by the 26S rDNA D1/D2 region and ITS region. This strain was used to evaluate the antifungal activity of thirty Chinese traditional herbal medicine extracts, and a modified dish dilution method was developed for the evaluation. Saprolegnia-infected rapeseeds with visible hyphae were transplanted onto prepared PDA plates containing 2 g L À1 herbal plant extracts and incubated at 20°C for 48 h. Each herbal plant species was tested in triplicate. Those herbal plant extracts that showed negative mycelium presence at 2 g L À1 were further tested for minimum inhibitory concentration (MIC) evaluation. The results showed that Syzygium aromaticum, Magnolia officinalis, Melaphis chinensis, Euphorbia fischeriana Steud, and Sophora flavescentis exhibited enhanced growth inhibition at 2 g L À1 and MIC values of 500, 62.5, 250, 62.5, 250 mg L À1 concentrations, respectively. It was obvious that Magnolia officinalis and Euphorbia fischeriana Steud exhibited the best antifungal activity. Since there is a high natural toxicity in Euphorbia fischeriana Steud, its applicability as the main ingredient in an aquaculture therapeutic formulation requires further research. Thus, Magnolia officinalis would appear to be the more valuable antifungal herbal species with which to pursue further research.

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“…() to have useful antifungal activity; however, our results and those of Cao et al. () noted that Cnidium monnieri did not inhibit Saprolegnia sp. growth.…”

Section: Discussioncontrasting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

The in vitro antifungal activity of 30 Chinese herb extracts to Saprolegnia sp.

et al. 2015

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“…Kitancharoen, Yuasa and Hatai () found that abundance and duration of motile zoospore production of S. diclina and S. parasitica are inversely related with temperature. On the other hand, zoospore production of pathogenic Saprolegnia ferax isolate was optimal at 20°C in vitro (Cao, Zheng, Xu, Ou, He & Yang ), while the production at 5°C was ~85% less than in optimal conditions. Furthermore, appearance of zoospores was delayed for 30 h at 5°C compared to optimal conditions.…”

Section: Discussionmentioning

confidence: 99%

Suppression ofSaprolegniainfections in rainbow trout (Oncorhynchus mykiss) eggs using protective bacteria and ultraviolet irradiation of the hatchery water

et al. 2014

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Since formalin is widely used in prevention of Saprolegnia infections in salmonid fish hatcheries, there is a need for more environmentally safe treatment methods. Therefore, we screened 360 bacterial isolates against their ability to antagonize the growth of Saprolegnia parasitica hyphae in vitro, and best strains were selected according to their antagonistic properties and colonization capability on rainbow trout egg surface. Protective bacterial cultures of Pseudomonas sp. M162, Pseudomonas sp. M174 and Janthinobacterium M169 were tested for prevention of Saprolegnia sp. infections during incubation trials of rainbow trout (Oncorhynchus mykiss) eggs with UV irradiated (400 mWs cm−2) and non‐treated inlet water. UV irradiation of inlet water significantly decreased mortality during the incubation. Lowest mortalities were observed in protective culture treated groups incubated with UV‐irradiated inlet water. UV irradiation increased the dominance of the main bacterial colonizers and variation in the bacterial species diversity between the experimental units.

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“…However, Saprolegnia australis (Czeczuga & Muszyńska ), S. ferax (Cao et al. ) and S. parasitica (Czeczuga & Muszyńska ; Songe et al . ) are also known to infect fish eggs.…”

Section: Introductionmentioning

confidence: 99%

A thicker chorion gives ova of Atlantic salmon (Salmo salar L.) the upper hand against Saprolegnia infections

Songe

Willems

Sarowar

et al. 2015

Journal of Fish Diseases

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Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.

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Identification of an isolate of Saprolegnia ferax as the causal agent of saprolegniosis of Yellow catfish (Pelteobagrus fulvidraco) eggs

Cited by 30 publications

References 25 publications

The in vitro antifungal activity of 30 Chinese herb extracts to Saprolegnia sp.

The in vitro antifungal activity of 30 Chinese herb extracts to Saprolegnia sp.

Suppression ofSaprolegniainfections in rainbow trout (Oncorhynchus mykiss) eggs using protective bacteria and ultraviolet irradiation of the hatchery water

A thicker chorion gives ova of Atlantic salmon (Salmo salar L.) the upper hand against Saprolegnia infections

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