Alleviation of rainbow trout egg softening caused by sodium hypochlorite as an antifungal agent

Kashiwagi, Masayuki; Kishihara, Tatsuya; Watanabe, T.; Inaba, Tadashi; Kato, T.; Ikushima, Satoshi; Khomvilai, Chutima; Yoshioka, Motoi

doi:10.1111/j.1444-2906.2007.01322.x

Cited by 6 publications

(6 citation statements)

References 2 publications

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“…Other compounds have also been investigated, for example, sodium hypochlorite (NaOCl) was thought to be a remarkable and effective antifungal chemical to prevent fungal infection on the eggs of white‐spotted char, Salvelinus leucomaenis , rainbow trout Oncorhynchus mykiss and chum salmon O. keta , but Kashiwagi et al. () found that it could lead to egg softening at certain concentrations. Good efficacy on control of S. parasitica infection in grass carps was observed with copper sulfate (Sun et al., ); Cao et al.…”

Section: Discussionmentioning

confidence: 99%

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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Section: Discussionmentioning

confidence: 99%

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

et al. 2015

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“…In intensive systems, disinfection treatments are routinely applied after egg hardening (i.e., fertilization) to reduce pathogens, but it is known that some chemical agents used for this purpose may have deleterious effects on chorion in a dose-dependent fashion. Kashiwagi et al [ 14 ] have reported that sodium hypochlorite applied after fertilization at 30 mg/L for 60-min every third day, but not 10 mg/L for 15-min daily, induces egg softening in Rainbow Trout. In Chile, the national regulatory agency (SERNAPESCA) dictates the compulsory use of (available) iodine given at a concentration of, at least, 100 ppm for 10-min, pH 6–8, for the disinfection of farmed egg.…”

Section: Discussionmentioning

confidence: 99%

“…Images were taken using a stereomicroscope (Olympus SMZ-2T; Olympus Co., Tokyo, Japan) attached with an upright digital camera (MicroPublisher 3.3 RTV; Q Imaging, Surrey, BC, Canada) controlled by a PC running the software Q-Capture Pro 5.1 (Q Imaging, Surrey, BC, Canada), which was also used to measure the diameter of eyed-eggs and morphometric parameters for the characterization of chorion alterations. For the determination of the chorion strength, we used a modified push–pull force gauge as described by Kashiwagi et al [ 14 ]; a fixed value of 100 g was applied and flattened or invaginated eyed-eggs after the pressure application were categorized as soft chorion.…”

Section: Methodsmentioning

confidence: 99%

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

Valdebenito

Figueroa

Valdebenito

et al. 2021

Animals

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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.

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Section: Analysis Of Variance For the Egg Hardnessmentioning

confidence: 99%

“…The softening seems to be a major reason why NaOCl has not been discussed as a suitable drug for fishery use, though the actual harm of softening is not clear. Under these circumstances, Kashiwagi et al 10 indicated that eggs of rainbow trout Oncorhynchus mykiss did not soften with NaOCl treatment at 10 mg/L with daily 15-min exposure. It has been known 9 that the same treatment with NaOCl is effective in controlling fungal infections on the eggs of chum salmon Oncorhynchus keta, and maintaining a higher percentage of their eying.…”

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confidence: 99%