Papel de las actividades superóxido dismutasa y catalasa en la ...

RESULTS AND DISCUSSION
dominant species will produce simpler patterns and the less abundant species may not
adequately represent in the community pattern. Moreover, the technique has limitations,
and it is possible that some of these bands may not be individual species, as
theoretically is defined, but rather groups which have the same relative G+C content and
have comigrated (Simpson et al., 1999; Temmerman et al., 2003). These limitations may
account in part for the decreased band number and may also have influenced the
apparent diversity and similarity values (McCraken et al., 2001).
The obtained results do not demonstrate that probiotics induce significant shifts in
intestinal microbiota, since bands that appear in groups fed with probiotics are also
present in control groups.
On the other hand, it is not possible to confirm that observed bands correspond to
Pdp11 or Pdp13, strains only attending to electrophoretic mobility, therefore,
phylogenetic identification or PCR products sequencing studies will be necessary. After
this work it is possible to affirm that Pdp11 and Pdp13 strains are not capable, at doses
(10 9 ufc g -1 ) and time assayed (two months), to induce significant shifts in intestinal
microbiota. However to exert a local effect during transit through gastrointestinal
system it is not necessary colonization to induce shifts on intestinal microbiota
(Ouwehand et al., 2002). In fact, variation of fish microbiota is substantial and fluctuates
daily (Spanggaard et al., 2000; Al-Harbi and Naim Uddin, 2004; Panigrahi et al., 2004).
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