EFFECTS OF SACCHAROMYCES CEREVISIAE VAR
BOULARDII ON INTERLEUKIN-1β EXPRESSION AND GUT
MORPHOMETRY IN EUROPEAN SEA BASS: PRELIMINARY
RESULTS.
G. Maricchiolo1*, M.C. Guerrera1, M. Castex2, F. Gai3, V. Parisi4, A. Perdichizzi1, L.
Genovese1 and S. Gangemi5
1Institute
for Coastal Marine Environment (IAMC), CNR U.O.S. Messina. Spianata S. Raineri, 86
98122 Messina (ITALY).
2 Lallemand Animal Nutrition, Blagnac, France. 3 Institute of Science of Food Production, CNR,
Grugliasco (TO). 4 Department of Veterinary Science, University of Messina. 5 Department of
Clinical and Experimental Medicine, School of Allergy and Clinical Immunology, University of
Messina.
Email: giulia.maricchiolo@iamc.cnr.it
Introduction
Probiotics, according to currently adopted definition of World Health Organization, are
“live microoorganisms that when administered in adequate amounts confer a beneficial
health effect on the host” (WHO, 2001). In aquaculture, probiotics are opening a new era
in the health management strategies, because, also for aquatic species, are counted
among functional foods,. In particular, probiotics are able to colonize and multiply in the
gut of host. They positively influence the physiology of the host organism by modulating
mucosal and systemic immunity, as well as, by improving the nutritional and microbial
balance in the intestinal tract (Balcazar et al., 2006; Mohapatra et al., 2012). Currently,
the specific literature underlines the numerous beneficial effects in fish of these useful
microbes, but their mechanisms of action are still little known and need to be explored.
Here, is presented a preliminary insight into the effects of Saccharomyes cerevisiae var
boulardii on some gut mucosa changes and local expression of interleukin-1ß (IL-1ß) in
European seabass, Dicentrarchus labrax. We report some preliminary data of a more
complete systemic study in which are considered numerous indicators of health status.
Materials and methods
The experiment was carried out in the Aquaculture Experimental Plant, Institute for
Coastal Marine Environment, Messina (Italy). Four hundred ninety-five seabass (average
weight 170 g) were used to assess the effect of diets enriched with Saccharomyes
cerevisiae var boulardii. The commercial probiotic was, Levucell (LSB) SB20®
(Lallemand Animal Nutrition, Blagnac, France) formulated with live S. cerevisiae
CNCM I-1079. Three diets containing 0 (LSB0), 100 (LSB100) and 300 (LSB300) mg
kg-1 of freeze-dried yeast were prepared. Each treatment was conducted in triplicate.
Fish were fed 1,2-1,7% biomass day-1, provided in equal rations at 9 am and 17 pm, for
90 days. Samplings were conducted after 21 and 45 days of feeding and at the end of
experimental period. The expression of gene interleukin-1ß was examined in the
proximal and distal tract of gut. Each sample was homogenized and total RNA extracted
with Trizol Reagent method (Invitrogen, USA). cDNA was synthesized using the High
Capacity cDNA Archive Kit (Applied Biosystems, USA) following the manufacturer's
instructions. Primers used were designed on the basis of the published sequences for
Dicentrarchus labrax (GeneBank). RT-PCR was performed in triplicate using a 7300
Real-Time PCR System (Applied Biosystems). Results were quantified using the 2-∆∆CT
algorithm and expressed as ± n-fold difference versus standard. Standard histological
analyses were carried out to evaluate morphological features of gut mucosa. Data were
analyzed to determine significant differences by means of the Mann-Whitney U Test.
Results
The relative expression of IL-1ß gene in distal gut is shown in Fig. 1. It was significantly
(p < 0,05) lower in LSB100 group after 21 days of probiotic feeding. There was no
significant difference among control and LSB300 group.
The proximal gut of LSB100-fed group showed a significantly (p < 0,05) increase in the
length of mucosal villi compared with the fish fed the control diet (336,9 ± 87,93 μm
versus 316,5 ± 87,93 μm).
Fig.1. RT-PCR analysys of IL-1ß gene expression in sea bass distal gut after 21 days of probiotic feeding.
LSB0: control; LSB100: 100 mg Kg-1 S. cerevisiae; LSB300: 300 mg Kg-1 S. cerevisiae. Each value represents
the mean ± S.E. of independent RT-PCR reaction of three replicates. Significant difference (p < 0,05) from the
control group is indicated by an asterisk.
Discussion and conclusions
In our study, Saccharomyes cerevisiae var boulardii induces significantly lower IL-1ß
expression in distal gut compared to the control, implying the involvement of the
probiotic, through this mediator, in immune response.
The same trend of IL-1ß expression is reported by Coves et al., 2011 in Atlantic bluefin
tuna larvae fed with Pedicoccus acidilactici; the authors, in fact, observe a downregulation of IL-1ß gene expression in the larvae fed with probiotic compared to control.
Interesting, also, the reaction of the intestinal mucosa to probiotic treatment. We observe
an increasing in the length of villi in LSB100 group considered as a positive response of
the mucosa being indicator of a greater absorption capacity.
This results, although preliminary, might indicate a positive effect of S. cerevisiae on sea
bass health and inflammatory status which, however, needs to be further confirmed.
Acknowledgments
This work was founded by the project INNOVAQUA - PON02_00451_3362185
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