enzymes (Finnie et al., 1995; Hamer et al., 2008). The
in vitro
expression of
mucin epithelial genes (MUC) has been shown to increase after butyrate
administration (Gaudier et al., 2004). Other components of the intestinal
defense barrier being influenced by butyrate are transglutaminase which is
actively involved in mucosal healing (D´Argenio et al., 2005), antimicrobial
peptides which protect the mucosa against the invasion and adherence
of bacteria and thereby prevent infection (Schauber et al., 2006; Sunkara
et al., 2011) and heat shock proteins which confer protection against
inflammation by suppressing the production of inflammatory modulators
(Malago et al., 2005).
Gustor Aqua is manufactured in both free and protected forms. While free
sodium butyrate maximizes the antimicrobial activity and confers trophic
and immunological properties in the upper-medium gastrointestinal tract
of fish, the protected product allows a gradual release of sodium butyrate,
therefore promoting antimicrobial, trophic and immunological effects along
the entire tract.
The efficacy of dietary supplementation of Gustor Aqua on performance
parameters have been evaluated in different aquatic species. In a trial carried
out at Nong Lam University (Vietnam) a catfish (
Pangasius hypohthalmus
)
diet was supplemented with 0.5 kg Gustor Aqua -free form)-per ton of feed
and fed twice daily during 56 days. Results (Table 7) showed significant
improvements in weight gain (+35%), specific growth rate (SGR) (+30%),
feed conversion ratio (FCR) (-16%) and protein efficiency ratio (PER) (+35%)
relative to the non-supplemented diet. In a second trial conducted at the
College of Aquaculture and Fisheries at Can Tho University (Vietnam) a
shrimp (
Penaeus monodon
) diet was supplemented with 1 kg of Gustor Aqua
-protected form- per ton of feed and fed during two months. Coefficients
of digestibility were determined by the use of chromic oxide as an inert
marker. As shown in Table 8 the supplementation of protected sodium
butyrate significantly enhanced digestibility of dry matter (DMd) (+12%),
crude protein (CPd) (+5%) and energy (Ed) (+7%) leading to numerical
improvements in weight gain, survival and FCR. In both experiments the
positive outcomes are attributed to the abovementioned modes of action
described for sodium butyrate.
Table 7. Effect of dietary supplementation of GUSTOR Aqua (free form) on
performance parameters of catfish (
P. hypohthalmus
)
Initial weight (g)
Weight gain (g)
SGR (% day)
FCR PER
Control
6.90
a
37.56
a
3.34
a
1.65
a
1.34
a
GUSTOR
Aqua
6.75
a
50.68
b
4.32
b
1.39
b
1.81
b
Gustor Aqua dosed at 0.5 kg/ton feed
Means with different superscripts in the same column are significantly different (P<0.05)
SGR: Specific growth rate/FCR: Feed conversion ratio/PER: Protein efficiency ratio
20
Natural growth promoters in aquaculture practices
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