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International Journal of Marine Science 2013, Vol.3, No.40, 319-332
http://ijms.sophiapublisher.com
321
1.2 Bacterial counts
No significant difference in THB, TVLO and LB
abundance was found between ponds. Hence, the bacterial
counts from the two ponds were pooled to obtain average
values (n = 6). Fortnightly variations in counts of THB,
TVLO and LB in different shrimp pond components
(source water and sediment, rearing water and sediment
and shrimp hepatopancreas) are depicted in Figures 1 a-e.
Figures 1a-e Fortnightly changes in the abundance of total heterotrophic bacteria (THB), total
Vibrio
like organisms (TVLO) and
luminescent bacteria (LB) in creek water (a), creek sediment (b), pond water (c), pond sediment (d) and shrimp hepatopancreas (e)
during the cultivation of
P. monodon
. Vertical bars denote standard deviation
Counts of total heterotrophic bacteria (THB) in the
pond water did not vary much and remained at 10
3
CFU mL
-1
throughout the culture period. In the pond
sediments, their abundance varied from 10
4
CFU g
-1
at
the beginning of the culture period decreasing to 10
2
CFU g
-1
towards the end of the culture period. The
abundance of THB in the source water also followed a
similar pattern as in the ponds. However, in shrimp
hepatopancreas, their numbers were 1-2 orders higher
at 10
4-5
CFU g
-1
.
The abundance of TVLO observed in rearing water
was not significantly different from that of source
water. In the culture ponds and source water, TVLO
were low on 0-doc (0.02 × 10
3
CFU mL
-1
) but
increased by 2 orders at 30-doc. Thereafter, their
numbers reduced by 60-doc coinciding with water
exchange. The abundance of TVLO in creek and pond
sediments followed a similar pattern of abundance
through the culture period varying from 10
1-3
CFU g
-1
.
In shrimp hepatopancreas, the TVLO abundance was
significantly higher and varied from 10
4-5
CFU g
-1
.
The LB in the source water and ponds followed a
similar pattern of abundance through the culture
period varying between 0.01-1.46 × 10
3
CFU mL
-1
. In