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International Journal of Aquaculture 2012, Vol.2, No.3, 11
-
14
http://ija.sophiapublisher.com
12
10
9
kob/g. Bacteria load and dominant species in the
intestinal flora change according to the feeding
regimen. In a study in which sea bass larvae were fed
with different feeds (commercial diet, including
artemia and iron) for 20 days, bacteria levels were
found to be 10
9
kob/g, 10
7
kob/g and 10
8
kob/g,
respectively, and dominant species differed in every
group (Reuter, 2001).
At the beginning of the feeding, the number of lactic
acid bacteria was at a level of 10
4
kob/g, there was an
increase in the groups fed by feeds containing
probiotic, and probiotic + prebiotic during the feeding
period. The number of lactic acid bacteria stayed the
same at the end of the 60-day feeding period in the
control group. In the groups containing probiotic, the
number of lactic acid bacteria increased during the
feeding period and approximately reached a level of
10
6
kob/g. When K1 species of
Carnobacterium
sp.
was added to the feed by 5×10
10
kob/g as probiotic, it
was reported that the number of probiotic bacteria in
the intestinal flora at the beginning was lower than the
identifiable level, and the number reached a maximum
(1.3×10
8
kob/g) on day 7, and decreased to a level of
2.9×10
5
on the last day of feeding (Jöborn et al., 1997).
The number of lactic acid bacteria of the intestinal
samples of trout during feeding increased until the 30
th
day of feeding, decreased on the 45
th
day, and
increased again on the 60th day and reached a level of
5.06 log kob/g. The lowest and the highest meanvalues
were identified on day 0 and day 60, respectively.
The values that belong to the 15
th
and 30
th
days of
the feeding were found to be statistically insignificant
(p>0.05) (Figure 1).
Figure 1 Count lactic acid bacteria for feeding period
Similar to our results, Dulluç (2010) reported that the
number of probiotic bacteria of baby tilapias that were
fed by feeds containing probiotic bacteria at different
levels (10
5
kob/g, 10
6
kob/g and 10
7
kob/g) were 4.37
log kob/g, 3.70 log kob/g, and 5.08 log kob/g,
respectively. The results of a study investigating the
effects of Carnobac terium spp. on Atlantic salmon and
rainbow trout intestinal load were in parallel with our
study (Robertson et al., 2000).
The level of Enterobacteriaceae was found to be at a
level of 10
3
kob/g on the first day of feeding in all
treatment groups. The numbers remained at the same
level in the groups fed by feeds containing prebiotic
and controls during the feeding period. On the other
hand, in groups containing probiotic, the number of
Enterobacteriaceae decreased to a lower than measurable
level on the 15
th
day. The same results were obtained
on the other days of feeding in these groups (p<0.01).
These results demonstrate that probiotics have an
important inhibiting effect on Gram negative bacteria.
According to this, the differences of the means of the
groups of probiotic + prebiotic and the control group
are higher than 1 logarithmic unit. According to this,
probiotics cause a remarkable reduction in the number
of Enterobacteriaceae (Figure 2).
Figure 2 Count of enterobacteriaceae for feeding period
Similar results were identified by Burr and Gatlin
(2005) and these researchers reported that probiotic
bacteria in fish intestinal flora have an inhibiting
effect on Enterobectericeae and coliform bacteria,
and by adherence to the intestinal lumen of some
microorganisms, they inhibit their growth. Similarly,
Öztürk (2008) reported that feeding carp with feed
containing probiotic (
Enterococcus faecium
) had an
inhibiting effect on Enterobacteriaceae and that the
number of Enterobacteriaceae decreased to a lower
than measurable level due to probiotic use. Bagheri et
al (2008) suggested that lactic acid bacteria compete
with the pathogeneous microorganisms in the intestinal
flora and inhibit their growth.