Prebiotics in Finfish: An Update - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 387

week trial in a closed circulation system. In the second sub-trial, prebiotics were tested using
diets with FM and SBM inclusion in 6 week trials conducted in either closed (the same cir-
culation system as sub-trial 1) or open (with independent biofilters for each tank) circulation
systems. In sub-trial 2, the authors wanted to examine whether the circulation system interacted
with the effect from the prebiotics supplementation. The results from the first sub-trial showed
that growth parameters such as weight gain, FCR and PER remained unaffected for both pre-
biotics. Whole body proximate composition showed that ash and lipid contents were similar
for all diets. Protein content was reduced for both prebiotics compared with the basal diet.
Inulin supplementation increased the moisture content compared to the basal diet. The results
from the second sub-trial revealed that weight gain, FCR, PER and whole body proximate
composition remained unaffected by the prebiotic supplementations. Similarly, the two circu-
lation systems did not affect any of these parameters. Microbial fingerprint was also examined
in sub-trial 2. Intestinal samples from fish and samples from systems biofilters were anal-
ysed using PCR-DGGE. There were no differences in the intestinal microbiota between the
feeding regimes.
Buentello et al . (2010) evaluated the effect of supplementation of FOS, MOS, TOS and
GroBiotic ® -A to SBM based diets on weight gain, feed efficiency and non-specific immunity
of red drum after challenge with Amyloodinium ocellatum , more commonly known as marine
velvet, which is one of the most frequently encountered pathogens affecting tropical marine
ornamental fishes. Prebiotics supplementation significantly improved feed efficiency, serum
lysozyme, intracellular superoxide anion production and survival after challenge.
Zhou et al . (2010) evaluated four different prebiotics; FOS, GOS, MOS and Previda™.
Each prebiotic was supplemented to a basal diet at a level of 10 g kg −1 . Fish fed Previda™ had
significantly higher weight gain compared to fish fed the basal diet or MOS supplemented diet.
Fish fed MOS displayed lower survival rates than the fish fed the other four diets. HSI, muscle
ratio, CF and morphological changes of the gut (fold and enterocyte height) were not affected
by prebiotics. Microvilli heights in the pyloric caeca, proximal intestine and mid intestine were
significantly increased by all prebiotics, but the microvilli heights in the distal intestine were
not affected.
14.11 OTHER FISH SPECIES
Beyond the aforementioned fish species, the effects of prebiotics on various other species have
been reported (Table 14.9). For example, raftilin, raftilose, lactosucrose, MOS and chitosan
oligosaccharides (COS) have been investigated in flatfish (Mahious et al . 2006b; Dimitroglou
et al . 2011c; Cui et al . 2012). In an 8 week feeding trial, Cui et al . (2012) evaluated the effect
of feeding turbot (∼12 g) several graded inclusion levels (0.075, 0.15, 0.3, 0.6 and 1.2 g kg −1 )
of COS on growth, innate immune responses and resistance against IP injection with Edward-
siella tarda . The results showed that an inclusion level of 0.3 g COS kg −1 improved SGR,
FCR, phagocytic index, serum superoxide dismutase activity, and survival against Ed . tarda
challenge. However, no effect was observed in malondialdehyde and metallothionein. In a
Senegalese sole study, vaccinated and unvaccinated fish (∼45 g) were fed 4 g MOS kg −1 after a
natural outbreak of pasteurellosis, caused by Photobacteriumdamselae subsp. piscicida (Dim-
itroglou et al . 2011c). After 10 weeks the mortality was significantly lower in MOS fed fish
and histological examination of the anterior and the posterior intestine using light microscopy