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Monastir, Tunisia

Lamari F.,French Research Institute for Exploitation of the Sea | Lamari F.,Laboratoire Analyse | Castex M.,British Petroleum | Larcher T.,French National Institute for Agricultural Research | And 4 more authors.

Probiotics may have many effects on health and development of fish larvae. One of the most promising is related to spinal conformation, though the mode of action is not clearly understood. The present study attempted to investigate the effects of two strains of lactic acid bacteria on associated microbiota, histological development and gene expression. Sea bass larvae were fed since 5 dph (day post hatch) with either a standard control diet (Diet C), or the same diet supplemented with Pediococcus acidilactici MA18/5M (Diet P), or with an autochthonous strain of Lactobacillus casei (X2; Diet L). The two lactic acid bacteria were incorporated in the diets at the levels of 106 and 107CFU (colony forming units) g-1 in two consecutive experiments, respectively. The experimental treatments maintained the lactic acid bacteria above the detection threshold in the larvae. In the second experiment, the Bray-Curtis indices revealed the dissimilarity between the Bacterial Community Profiles (BCPs) associated with Diet P and those of the two other dietary groups. The two lactic acid bacteria promoted growth, especially by 20-22 dph, but the development seemed affected differently in the two groups. The osteocalcin gene was overexpressed at 20-22 dph in group L, suggesting a difference in the early bone development compared with Group P. A possible consequence was the highest incidence of spinal deformities in Group L. At day 62 dph, the ossification was achieved and normal in 60% of the larvae in Group P, whereas this rate was only 13 and 19% in Groups C and L, respectively. The evaluation of probiotics should not be therefore limited to growth measurements, and should take into account ontogenetic chronology for improving larval quality with such treatments. © 2012 Elsevier B.V. Source

Bouaicha A.,Laboratoire Analyse | Allagui H.,Laboratoire Analyse | Mami A.,Laboratoire Analyse | Rouane A.,University of Lorraine
2013 10th International Multi-Conference on Systems, Signals and Devices, SSD 2013

In order to further understanding the behavior of PEM fuel cell and optimize their performance, it is necessary to perform measurements in real time. The measure of internal impedance of a fuel cell in load is of great importance. In this work, we present the impedance measurement method of a PEM fuel cell by electrochemical impedance spectroscopy method (EIS), as well the study of an electronic load for the implementation of the measurement technique. The theoretical results are obtained by a simulation with PSPICE software. © 2013 IEEE. Source

Lamari F.,Laboratoire Analyse | Sadok K.,Laboratoire Analyse | Bakhrouf A.,Laboratoire Analyse | Gatesoupe F.-J.,French National Institute for Agricultural Research
Aquaculture International

Lactic acid bacteria (LAB) were isolated from rotifer cultures in a marine hatchery to search for potential probiotics for marine animals. Fifteen strains were first selected among a total of 55, according to antibacterial activity against Vibrio sp. Among eight strains identified as Lactobacillus casei, four were highly adhesive, suggesting some ability for surface colonization. The other strains were identified as Lactobacillus plantarum, Lactobacillus dextrinicus, and Leuconostoc sp. To validate probiotic potential, Artemia were challenged against pathogenic Vibrio alginolyticus, with or without one of six selected LAB strains. The six strains protected Artemia against the pathogen, to some extent on condition that nutrient enrichment was provided. La. casei BR51 and X2 were preferred, as they were efficient even in the absence of nutrient supply. La. casei X2 was finally selected as candidate probiotic, due to the best growth performances of Artemia, with or without the pathogen. © 2013 Springer Science+Business Media Dordrecht. Source

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