Bacterial microbiota of eggs
from cage-reared and tank-reared grouper, Epinephelus coioides
E.A.
Tendencia-2004
Bulletin
of the European Association of Fish Pathologists, 24(3): 161-165 (from ISI Current Contents)
Abstract:
At SEAFDEC AQD, opaque spawned grouper eggs are observed during collection
in cage-reared brood stock; while opaque and multi-colored eggs are often
observed in tank-reared fishes. This study aimed to investigate the
occurrence of these opaque and multicolored eggs and at the same time to
compare the bacterial microbiota of eggs from brood stock reared in cages,
to those from fish reared in concrete tanks. Grouper eggs from brood stocks
reared in cages and tanks were processed for bacterial count and
identification. Results showed that total bacterial count (on MA) and
presumptive Vibrio count (on TCBS) of eggs from brood stock reared in
concrete tanks were lower than those from cage-reared fishes. Aeromonads
(for tank-reared) and Pseudomonads (for cage-reared) were the dominant
bacteria in the good eggs; while Vibrios were dominant in the bad eggs for
both egg sources. Total bacterial count of the egg-incubating medium from
the brood stock tanks (10(4) cfu/ml) was lower than the total bacterial
count of water from the cages (10(7) cfu/ml). Presumptive Vibrio counts of
water from the tanks (10(2) cfu/ml) were lower than those from the cages
(10(6) cfu/ml). The Aeromonads dominated the water from the tanks; while
Vibrios dominated those from the cages. Good eggs that did not hatch, turned
yellow after 3 days, and pink after 5 days.
(SE Asian Fisheries Dev. Ctr., Dept. of Aquaculture,
Tigbauan 5021, Philippines)