Prebiotics in Finfish: An Update - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 389

revealed that MOS supplementation increased villi folding compared to the control fish. Scan-
ning electron microscopy revealed that MOS promoted microvilli structures of better quality
and with greater density in the anterior part of the intestine. These results were in agreement
with the previous MOS applications in fish and strengthen the suggestion that MOS produce
a positive effect in the overall intestinal morphology, function and efficiency.
In Poeciliidae, Abasali and Mohamad (2011a; 2011b) carried out studies to evaluate if
dietary Immunogen (5, 10 and 15 g kg −1 ) affected platy ( Xiphophorus maculatus ) and sword-
tail ( Xiphophorus helleri ) reproductivity. Gonadosomatic index (GSI), relative fecundity,
fry production per female and fry survival were significantly higher when platy were fed
15 g Immunogen kg −1 . Swordtail showed significantly higher growth when fed 10 and 15 g
Immunogen kg −1 , while the highest GSI was observed in fish fed 10 g kg −1 Immunogen. The
authors suggested that their findings were attributed to balanced production of essential nutri-
ents. However, no convincing experiments have been conducted so far to validate this hypothe-
sis and, as the authors suggested, further studies are needed to clarify the mechanisms involved.
Recently, Mouriño et al . (2012) evaluated the effect of dietary inulin (5 g kg −1 )onthe
autochthonous gut microbiota, haematological and immunological parameters of hybrid soru-
bims ( Pseudoplatystoma corruscans and Pseudoplatystoma fasciatum ). Inclusion of inulin
did not affect total gut bacterial levels or Vibrio levels; however, Pseudomonas levels were
decreased and LAB levels increased. None of the haematological parameters investigated
were affected by dietary inulin and, of the immunological parameters evaluated, only total
immunoglobulin was affected, which was increased from 1.80 ± 0.58 mg ml −1 in the control
group compared to 4.17 ± 0.84 mg ml −1 in the inulin group.
14.12 SYNBIOTICS
Synbiotics are nutritional supplements combining a mixture of probiotics and prebiotics in a
form of synergism, which beneficially affect the host by improving the survival and imple-
mentation of live microbial dietary supplements in the GI tract of the host (Andersson et al .
2001). Since the first study on synbiotics in fish published in 2009 (Rodriguez-Estrada et al .
2009) there has been a growing interest in the use of synbiotics in aquaculture and recently
Cerezuela et al . (2011) published a review on this topic. Since this review was published sev-
eral further synbiotic studies have emerged (Table 14.10). These studies have assessed growth
performance, feed utilization, digestive enzyme activities, body composition, immunologi-
cal responses, haematological/serum biochemical parameters, disease resistance, survival rate
and gut microbiota of synbiotic fed finfish, shellfish and echinoderms. Readers with a special
interest in prebiotics and synbiotics in crustaceans are referred to Chapter 15 . To avoid dupli-
cation, the studies reviewed comprehensively by Cerezuela et al . (2011) are not discussed in
this section and readers with a special interest are referred to the original review.
Firouzbakhsh etal . (2012) evaluated the effect of Biomin IMBO ( Enterococcusfaecium and
FOS; 0.5, 1, 1.5 g kg −1 ) on rainbow trout SGR, FCR, feed conversion efficiency (FCE), sur-
vival and disease resistance towards Saprolegnia parasitica . All inclusion levels significantly
improved SGR, FCE, survival and resistance against S. parasitica while FCR and CF were
reduced. Similar improvements in growth, and in some cases survival, have been observed
with the application of commercial synbiotic Biomin IMBO to kutum (Haghighi et al . 2010),
angelfish ( Pterophyllum scalare ) and zebrafish ( Danio rerio ) (Nekoubin et al . 2012b).