Volume 209, Issues 3–4, 30 April 2015, Pages 235–241
Efficacy of ginger-based treatments against infection with Gyrodactylus turnbulli in the guppy (Poecilia reticulata (Peters))
Highlights
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- Parasitic infections of fish result in high mortalities and economic losses.
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- Natural plant-based treatments offer alternative disease control strategies.
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- Ginger-based products eliminate monogeneans in guppies.
Abstract
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 ± 0.2 min, respectively, whereas at 5 and 40 ppt ethanolic extract
parasites died at 26.1 ± 0.7 and 4.9 ± 0.3 min, 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.
Keywords
- Gyrodactylid;
- Monogenea;
- Natural treatments;
- Parasite control;
- Zingiber officinale
- Corresponding author. Tel.:
+972 506612343; fax: +972 8 6596742.
Copyright © 2015 Elsevier B.V. All rights reserved.
