INTERNATIONAL JOURNAL OF AGRICULTURAL TECHNOLOGY

Volume 14, No. 07, Month DECEMBER, Year 2018, Pages 2191 - 2206

Efficacy of herbal extracts to control multi-antibiotics resistant (mar) aeromonas veronii isolated from motile aeromonas septicemia (mas)-exhibiting nile tilapia (oreochromis niloticus)

U-taynapun, K., Mueangkan, N. and Chirapongsatonku, N.

Abstract Download PDF

Motile Aeromonas septicemia (MAS) is a disease causing a devastating loss in fish farming including Nile tilapia (Oreochromis niloticus). The disease is caused by pathogenic bacteria Aeromonas spp. Our previous study has revealed that A. verronii is one of commonly isolated species from the MAS–expressing Nile tilapia cultured in Southern Thailand. Among the collected bacteria, one isolate exhibiting multi-antibiotic resistance (MAR) against tetracycline and oxyteracycline was selected as a model for testing the biological control ability of herbal extracts. The herbal extracts obtained from 6 herbal plants; Caesalpinia sappan (Cs), Allium sativum (As), Illicium verum (Iv), Alpinia galanga (Ag), Piper longum (Pl), and Foeniculum vulgare (Fv), extracted using 3 different solvents; 95% ethanol (E95), water (W) and soybean oil (O) were first screened for their inhibitory potential by disc diffusion method compared with tetracycline (30 μg). The clear zones (7–18 mm) were detected in Cs-E95, Cs- W, As-E95, Iv-E95, IV-W, and Ag-E95 while the clear zone in tetracycline was about 13 mm. All 6 herbal extracts showing clear zone were further evaluated for their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against the MAR–A. veronii. The greatest MIC of 0.469 mg/ml was recorded in Cs-E95 and Cs-W and MBC of 0.938 mg/ml in Cs-W. Moreover, the inhibitory effect of Cs-E95, at the concentration of MIC and MBC, on the growth of MAR–A. veronii cultured under the water temperature observed in the fish farm was also demonstrated. This finding revealed the potential of herbal extracts as a favorably health and environmental friendly approach in modern aquaculture to control the bacterial pathogens instead of using antibiotics.

Keywords

motile Aeromonas septicemia (MAS), Oreochromis niloticus, multi-antibiotics resistance (MAR), herbal extract, Aeromonas veronii

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