Prebiotics in Finfish: An Update - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 369

However the survival rate, haematological and serum biochemical parameters were not signif-
icantly affected by dietary yeast. Although no substantial effects were observed on the total
autochthonous intestinal heterotrophic bacterial levels, the autochthonous LAB levels were
significantly elevated in beluga fed 20 g yeast kg −1 .
Feeding 10 and 30 g kg −1 of Immunoster™, a commercial prebiotic containing MOS and
β-glucans derived from the cell wall of a single source of brewer's yeast, or ImmunoWall, a pre-
biotic mixture of polysaccharides derived from the cell wall of S.cerevisiae , to beluga juveniles
(ca. 95 g) in two 8 week trials, Ta'ati etal . (2011a; 2011b) showed that these prebiotic products
significantly increased growth performance. Although some haematological parameters were
affected (e.g. MCV, MCH, lymphocytes and eosinophils), no significant effects were observed
in the immune parameters investigated (IgM and serum lysozyme) (Ta'ati et al . 2011a).
Razaghi Mansour et al . (2012) reported results from a study evaluating dietary inclusion
of MOS at 2 and 4 g kg −1 on growth performance, haematological parameters and intestinal
LAB levels of beluga juveniles (46.89 ± 2.57 g). The results of this study showed that MOS
did not influence growth performance, haematological parameters or LAB levels in the gut.
Mohajer Esterabadi et al . (2010) tested four inclusion levels (5, 10, 20 and 40 g kg −1 )of
Immunogen ® , a commercial prebiotic containing 30% glucans and 18% MOS, on growth
performance on beluga in an 8 week experiment. The authors reported significant improvement
in SGR, length and CF in fish fed diets containing 0.5 and 1% Immunogen compared to the
control fish.
14.4.2 Siberian sturgeon
Recently, Geraylou et al . (2012) tested AXOS (AXOS-3-0.25, low degree of polymerization;
and AXOS-32-0.30, high degree of polymerization) on juvenile Siberian sturgeon growth per-
formance, immune responses and allochthonous hindgut microbiota. Both supplementations
enhanced the phagocytic activity of macrophages, while the alternative haemolytic comple-
ment activity and total serum peroxidase content improved only in fish fed AXOS-32-0.30.
Neither AXOS preparation affected growth performance, serum lysozyme activity and
superoxide dismutase. Inclusion of AXOS however modulated the allochthonous hindgut
microbiota: for example, Clostridium colicanis , Clostridium baratii , Lactobacillus aviaries ,
Lactococcus raffinolactis, , Lactococcus lactis and Eubacterium budayi were uniquely present
in fish fed AXOS-32-0.30. The production of short chain fatty acids, the end products
of microbial fermentation, were significantly higher in fish fed AXOS-32-0.30 than in
AXOS-3-0.25 and the control group. Based on their results the authors concluded that AXOS
improved sturgeon health through prebiotic actions, but the induced effect is dependent on
the degree of polymerization.
14.5 CYPRINIDAE
Carps represent the largest group of cultured fish globally. In 2011, total carp production
exceeded 23 million tonnes with production predominantly in China, India and to a lesser
degree Eastern Europe. As such, prebiotic investigations have been undertaken with common
carp ( Cyprinus carpio ), koi carp ( Cyprinus carpio koi ), crucian carp ( Carassius auratus
gibelio ), gibel carp ( Carassius auratus ) and Indian carp ( Catla catla ) as well as a number
of other cyprinids: Caspian roach ( Rutilus rutilus ), kutum ( Rutilus frisii kutum ), goldfish