The Potential of Galangal (Alpinia galanga Linn.) Extract against the Pathogens that Cause White Feces Syndrome and Acute Hepatopancreatic Necrosis Disease (AHPND) in Pacific White Shrimp (Litopenaeus vannamei)

Tidaporn Chaweepack,Boonyee Muenthaisong,Surachart Chaweepack,Kaeko Kamei

doi:10.5539/ijb.v7n3p8

Abstract

White feces syndrome and acute hepatopancreatic necrosis disease (AHPND) are serious diseases that have recently been noted in Pacific white shrimp (Litopenaeus vannamei). Vibrio bacteria and 6 species of fungi (Aspergillus flavus, A. ochraceus, A. japonicus, Penicillium sp., Fusarium sp., and Cladosporium cladosporioides) were isolated from shrimp naturally infected with white feces syndrome. Antibiotics have been used to treatment the disease for many years, but these have been ineffective and have resulted in drug residue problems for the shrimp industry. In this study, an alternative method was tested for its efficacy in controlling these pathogens. The crude extract of galangal (Alpinia galanga Linn.), an herbal medicine, inhibited the growth of 8 vibrio species of the pathogen, V. parahaemolyticus (EMS/AHPND) in particular. The results also showed that 0.5 mg/ml of the galangal extract was a concentration that produced the strongest inhibition of the fungi A. ochraceus. Naturally infested shrimp L. vannamei were fed 2 and 4% (v/w) portions of the herb extract for 12 days and their progress was compared with that of a control group (no herb extract). At the end of the feeding trial, the numbers of total Vibrio spp. and the incidence of fungi infestation in the hepatopancreas and intestines of treated shrimp were significantly lower than that in the control group (P<0.05). Furthermore, the survival rates for the treatment groups, after injections with V. parahaemolyticus (EMS/AHPND), were significantly higher than that of the control group (P<0.05). Based on these results, we can report that the galangal extract has antimicrobial properties that are applicable as bio-medicinal agents against white feces syndrome and AHPND. Therefore, in the future this herb should be an alternative to chemotherapeutic agents that are being used in the shrimp industry.

Highlights

Disease outbreaks caused by viruses, bacteria and protozoa are important disease agents within the shrimp aquaculture, a major industry in Southeast Asia, because they can lead to serious economic losses for long periods of time
Pathogenic Vibrio species that included V. cholerae, V. parahaemolyticus, V. parahaemolyticus (EMS/acute hepatopancreatic necrosis disease (AHPND)), V. fluvialis, V. vulnificus, V. alginolyticus, V. mimicus, and V. harveyi were isolated from diseased Pacific white shrimp (L. vannamei) obtained from grow-out ponds in Chanthaburi Province, using the Ruangpan & Kitao (1991) method
Based on the results of the present study, we recommend alternative methods for control of the disease that causes white feces syndrome and AHPND in the shrimp industry by using galangal crude extract, which has proven to be effective and safe for the environment as well as for consumers. This investigation was focused on the efficacy of galangal extract for treatment of the pathogenic organisms that cause white feces syndrome and AHPND in Pacific white shrimp, L. vannamei

Summary

Introduction

Disease outbreaks caused by viruses, bacteria and protozoa are important disease agents within the shrimp aquaculture, a major industry in Southeast Asia, because they can lead to serious economic losses for long periods of time. These bacterial disease pathogens have grown rapidly due to global warming, which has stressed the shrimp population by reducing immunity and enhancing the infection rates. Shrimp was initially named Early Mortality Syndrome (EMS) in China. This disease was later referred to as Acute Hepatopancreatic Necrosis Disease (AHPND). Infestations of Gregarine protozoa and Vibrio bacteria have been found that caused loose shells, www.ccsenet.org/ijb

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Discussion

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