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

INTRODUCTION
Different mechanisms have been proposed to explain the types of interactions
between probiotics and pathogens: (1) Competitive exclussion, production of
antimicrobial compounds such as bacteriocines, lysozimes and proteases (Austin et al.,
1995; Sugita et al., 1997; Gatesoupe, 1999; Gram et al., 1999; Verschuere et al., 2000); (2)
competition for available energy and nutrients (Smith and Davey, 1993; Pybus et al.,
1994; Gatesoupe et al., 1997; Gram et al., 1999); (3) Adhesive interference in the host
(Olsson et al., 1992; Jöborn et al., 1997; Nikoskelainen et al., 2001; Chabrillón et al.,
2005a and b). Recently, research have focused also on the immunomodulatory properties
of probiotic microorganisms (Irianto and Austin, 2003; Nikoskelainen et al., 2003;
Panigrahi et al., 2004; Salinas et al., 2005, 2006; Díaz-Rosales, 2006) (Table 6).
The gastrointestinal microbiota plays an important role in host nutrition and
health. Therefore, probiotics could perform an interesting function, modifying
gastrointestinal microbiota to induce favourable effects, such as improvement of
growth, digestion, immunity or resistance against a pathogen. There are numerous
authors that have characterized gastrointestinal microbiota of different farmed fish,
fundamentally salmonids (Spanggaard et al., 2000; Huber et al., 2004, Jensen et al., 2004;
Burr et al., 2005), however studies on gastrointestinal microbiota characterization or
evaluation of possible effects of probiotics are null in fish from Mediterranean area.
These studies are very interesting since could provide information for a better
application of microorganisms in prophylactic strategies and diseases biocontrol.
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