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Abstract:
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Giant freshwater prawn, Macrobrachium rosenbergii
(de Man), is an important commercial species with
considerable export value, ideal for cultivation
under low saline conditions and in freshwater zones
(Kurup 1994). However, despite more than a
decade of research on its larval production systems,
vibriosis still hampers seed production resulting in
high mortality rates. Among the different species of
vibrios, Vibrio alginolyticus has been isolated frequently
from diseased shrimp as the aetiological
agent of vibriosis and has been described as a
principal pathogen of both penaeids and nonpenaeids
(Lightner 1988; Baticados, Cruz-Lacierda,
de la Cruz, Duremdez-Fernandez, Gacutan, Lavilla-
Pitogo & Lio-Po 1990; Mohney, Lightner & Bell
1994; Lee, Yu, Chen, Yang & Liu 1996). Vibrio
fluvialis, V. alginolyticus, V. cholerae non-O1
(Fujioka & Greco 1984), Aeromonas liquifaciens
and V. anguillarum (Colorni 1985) have been
isolated from the larvae of M. rosenbergii. A
profound relationship between the abundance of
members of the family Vibrionaceae and larval
mortality (Singh 1990) and the predominance of
Vibrio in eggs, larvae and post-larvae of
M. rosenbergii (Hameed, Rahaman, Alagan &
Yoganandhan 2003) was reported. The present
paper reports the isolation, characterization, pathogenicity
and antibiotic sensitivity of V. alginolyticus
associated with M. rosenbergii larvae during an
occurrence of severe mass mortality at the ninth
larval stage. |