International Journal of Aquaculture, 2017, Vol.7, No. 3, 15
-
22
18
Figure 5 Hepatopancreas of shrimp infected with
Vibrio mimicus
Note: Mag. ×400 H and E (Hemolysin and Eosin)
Imp: Unhealthy Hepatopancreas
1.4 Challenge test
No mortality was recorded in treatment group 1 (shrimp culture inoculated with
Pseudomonas
aeruginosa
and
challenged with
Vibrio mimicus
). The control group 2 with no addition of bacteria had 22% mortality while the
control group 3 infected with
Vibrio mimicus
recorded the highest mortality of 54% (Table 3). Statistical analyses
performed on the results of the water quality parameters measured during the culture period showed that the value
of each parameter in each treatment group was not significantly different. Moreover, the water quality parameters
were within the optimum ranges throughout the culture period (Table 4).
Table 3 Probiotic trial of
Pseudomonas aeruginosa
on shrimp (
Penaeus monodon
) culture challenged with
Vibrio mimicus
Treatment groups Bacterial cell (3 x 10
5
cfu/ml)
No of dead shrimp/ No tested (with time intervals)
Mortality (%)
Day 0
Day 3
Day 6
Day 9
Day 12
1
Pseudomonas aeruginosa
plus
Vibrio
mimicus
0/50
0/50
0/50
0/50
0/50
0
2
Non-infected control (habitat water
only)
0/50
1/50
3/50
7/50
11/50
22
3
Vibrio mimicus
0/50
8/50
12/50
19/50
27/50
54
Table 4 Water quality measurements during 12 days shrimp culture
Parameters
Optimum range (Suantika et al., 2013)
Culture range
pH
7.0-8.3
7.1-7.5
Temperature (
o
C)
28-32
27-28
Ammonia
(mg/L)
<0.03
0.021-0.027
Nitrate (mg/L)
<60
0.8-0.9
Nitrite (mg/L)
<1.0
0.01-0.03
Salinity (ppt)
0.5-35
20.1-20.2
Dissolve oxygen (mg/L)
5.0-9.0
7.44-7.52
2 Discussion
In the present study, molecular analysis carried out on the antagonistic
Pseudomonas
sp. Ps2 and pathogenic
Vibrio
sp. V1 previously isolated from healthy and moribund shrimp
(Penaeus monodon
) intestines (Ariole and
Aungwa, 2013) respectively, revealed that they are closely related to
Pseudomonas aeruginosa
(Figure 1) and
Vibrio
mimicus
(Figure 2) respectively.
Pseudomonas
and
Vibrio
are common dwellers of aquatic habitat
including ponds for shrimp culture and have been isolated by other workers (Vijayan et al., 2006; Chau et al.,
Swollen tubule
Degenerated connective tissue
Degenerated tubule lumen
Infected nucleus
Degenerated vacuole
