Efficacy of Aloe vera against the pathogen Aeromonas hydrophila infecting gold fish
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Date
2016-11-05
Authors
Dissanayaka, D.M.S.G.
De S. Jagoda, S.S.S.
Arulkanthan, A.
Wijesundara, R.R.M.K.K.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya, Sri Lanka
Abstract
Aloe vera, a herb with known antibacterial properties, has not been fully exploited in aquatic medicine. Therefore, the present study was conducted to evaluate the effectiveness of Aloe vera in gold fish experimentally infected with A. hydrophila, a strain isolated from a septicaemic gourami Trichopodus leerii.
To test the in vitro antibacterial effect of A. vera against the above strain, an agar gel diffusion test was employed using the supernatant of Aloe vera gel homogenate collected from fresh and mature leaves. In addition, to test the effect of A.vera against A.hydrophia in vivo, experimental feed number 1, 2 and 3 containing 20%, 33.3% and 42.9% of A.vera gel, was prepared respectively. Seventy two gold fish were divided into four groups (n=18; 6 fish per tank with three replicates) and the groups 1, 2 and 3 were fed with experimental feed number 1, 2 and 3, respectively while the group four was fed with a control feed without A.vera. All the above groups were fed with respective diets twice daily at a rate of 0.5 g per tank for 56 days. The body weights were taken at day 0 and day 42 of the experiment. On day 42, all fish from groups 1 to 4 were injected intraperitoneally with an overnight broth of A.hydrophila at a dose 2.42 × 10⁴ cfu per fish and observed daily for a period of 14 days.
A.vera gel supernatant inhibited the growth of A. hydrophila in a dose dependent manner in vitro. There is no statistical difference among the body weight gain of group 1 (0.7g), 2 (0.87g), 3 (0.87g) and 4 (0.65g) (p > 0.05). Further, upon artificial infection with A. hydrophila the survival rate of groups 1 (55.5%), 2 (66.6%), 3 (66.6%) were higher than that of control group (5.55%) (p < 0.05). The in vitro and in vivo effectiveness of A. vera against A. hydrophila suggests that A. vera can be used as a cheap alternative to antibiotics to control A.hydrophila infections in gold fish.
Description
Keywords
Aloe vera , Gold fish
Citation
Proceedings of the Peradeniya University International Research Sessions (iPURSE) – 2016, University of Peradeniya, P 349