Probiotic Applications in Temperate and Warm Water Fish Species - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 275

and HK respiratory activities were significantly elevated at all levels tested, but the improve-
ments were greatest in all cases in carp fed Ps. aeruginosa at 10 7 CFU g -1 . Many of these
immune responses, and improved resistance to A. hydrophila , were also reported when using
simultaneous combinations of B.subtilis , Ps.aeruginosa and Lb.plantarum (Giri etal. 2013b).
Gopalakannan and Arul (2011) demonstrated that dietary provision of E. faecium (RPS = 75
and 78 on days 30 and 60, respectively) and C. divergens (RPS = 50 and 61 on days 30 and
60, respectively) improved common carp resistance to A. hydrophila . Both probiotics also ele-
vated neutrophil NBT activity. Improved resistance of catla to A. hydrophila has also been
reported with Lb. plantarum and B. megaterium applications (Parthasarathy and Ravi 2011),
and koi carp fed B. subtilis displayed reduced, albeit not significantly, mortalities when chal-
lenged with A. hydrophila (He et al . 2011a). In addition, elevated hepatic expression of TNFα,
HSP70, TGF-β and IL-10 and intestinal expression of IL-1β,TNFα,TGF-β and IL-10 genes
were observed in B. subtilis fed koi (He et al . 2011a).
Although somewhat limited in their scope, these studies provide clear evidence that pro-
biotics can improve a number of immunological responses of carp species and that these
responses confer protection against A. hydrophila infections.
10.8 ZEBRAFISH ( DANIO RERIO )
The zebrafish and human genomes share extensive conserved synthenic fragments and
zebrafish is therefore increasingly seen as a powerful and highly amenable model system. The
zebrafish has been used to elucidate the molecular mechanisms involved in several different
physiological processes, including host-microbiome responses, and as such the model has
been used extensively to study probiotics (Table 10.7).
10.8.1 Effects of probiotic on zebrafish reproduction,
development and survival
A number of recent studies have evidenced the positive role of Lb. rhamnosus IMC 501 on
zebrafish gamete quality, spawning rates, oocyte growth and maturation, larval development,
fecundity, backbone calcification and the expression of genes which regulate growth, devel-
opment and immunity (Table 10.7). The roles of the probiotics in zebrafish development,
reproduction and nutrient metabolism have been reviewed by Carnevali et al . (2013) and again
here in Chapter 12 . Readers with a specific interest in this topic are directed to these reviews.
Further information is available with respect to modulation of the gastric microbiota, growth
performance, immunity and disease resistance.
10.8.2 Zebrafish immunity and disease resistance studies
The antimicrobial activities of Lb. plantarum JCM 1149 T (observed to have positive adhe-
sive capabilities to the zebrafish gut) and Lb. acidophilus JCM 1132 T (observed to be less
capable of adhering to the zebrafish gut) were assessed against A. hydrophila in vitro and
in vivo by Zhou et al . (2012a). Both probiotic strains showed strong, and similar, in vitro
antimicrobial activities against A. hydrophila . In the 2 week in vivo challenge study dietary
Lb. acidophilus JCM 1132 improved the survival rate by 3%, 7% and 37%, compared to the
control, when provided at 10 6 cell g -1 ,10 7 cell g -1 and 10 8 cell g -1 , respectively. However,