control of vibrio
spp. in shrimp hatcheries using the green algae tetraselmis suecica
C. Regunathan, S.G. Wesley-2004
Asian Fisheries Science, 17(1-2): 147-157
Abstract:
The Vibrio spp. Are the most common and
harmful shrimp pathogenic bacteria causing serous diseases of larval and
postlarval stages in the hatchery. The Vibrio inhibitory activity of
green algae Tetraselmis suecica has been reported in vitro (Austin
and Day 1990). In these experiments, the inhibitory activity was assessed in
vivo in a commercial shrimp hatchery of the white prawn Fenneropenaeus
indicus. The concentrate of the algae was used as a food supplement for
the broodstock and also as partial live larval feed in the larval rearing
tanks. Results showed that use of algae resulted in significant reduction of
Vibrio numbers in maturation and spawning tank water, broodstock gut
contents, egg and nauplii samples. The spawning tank water Vibrio
count showed a negative correlation with egg hatching rate. The algae when
used in larval tanks were found to reduce Vibrio count in both
rearing water and larval samples, resulting in improved nauplii 5 to
postlarvae 1 survival. Rearing tank experiments with axenic algae proved
that the inhibitory effect was by Tetraselmis and not by associated
bacteria. Usage of this algae in the hatcheries will be advantageous as it
suppresses the dominance of Vibrio spp. may be including the
potentially pathogenic ones.
(Aquaculture Division, Department of Zoology, Scott
Christian College, Nagercoil, Tamil Nadu, 629 003, India)