Effet du régime alimentaire sur la composition du ver de terre Eudrilus eugeniae

peer reviewedThe earthworm Eudrilus eugeniae is a well-known source of protein in animal feeding but there is lack of information on its fatty acid profile. This study aimed to determine its nutrient components and fatty acid profile. Earthworms were bred in substrate containing organic matter; peanut powder was added in the experimental group diet. The nutrient components (protein, ash, and minerals) of the adult worms were determined according to the Kjeldahl method and by atomic absorption spectrophotometer. The fatty acid profile was determined by gas chromatography / mass spectrometry. The dry-matter protein content significantly increased in worms fed peanut powder (p < 0.05) as did the minerals measured. The main fatty acid families had similar proportions in the groups. In the saturated fatty acids, C12:0 and C18:0 were present in higher proportions in both groups, whereas in monounsaturated fatty acids, C18:1ω9 prevailed. Significant differences (p < 0.05) in polyunsaturated fatty acids were observed between the two groups. An increase in the proportion of ω6 and ω3 was observed in the experimental group compared to the control. This study showed that peanut powder significantly influenced nutrient components of E. eugeniae. The fatty acid profile of this species was similar to that of most animals. Earthworms’ diet can be altered to improve the nutritional value of E. eugeniae

In vitro evaluation of the aryl hydrocarbon receptor transactivity induced by human intestinal metabolites

The gastrointestinal tract is directly exposed to the environment and constitutes one of the first lines of defense against harmful antigens in the diet or the microbiota. Highly expressed in intestinal cells, the aryl hydrocarbon receptor (AhR) plays a crucial role in gut mucosal integrity and in intestinal immune function. Substances derived from food and the microbiota in the intestinal lumen can induce AhR transcriptional activity and thus maintain intestinal barrier homeostasis. We suggested the combination of a simulator of the human gut microbial ecosystem (SHIME) with cell based AhR transactivity bioassays. Thereby, the effects of human gut microbiota metabolism on the AhR signaling pathways could be evaluated. Three AhR reporter gene cell lines (T47D, HepG2, HT29) from human mammary, hepatic, and intestinal tissues, respectively, were used to test mixtures of microbiota-derived metabolites that were generated in a 3-days experiment on a SHIME system. The SHIME samples induced an AhR agonist activation in the different cell lines, with slightly tissue-dependent effects. Microbiota produced metabolites, such as short-chain fatty acids (SCFA) and tryptophan catabolites were quantified chromatographically in the SHIME samples, and they might be causing the AhR agonist activity of the mixture. However, more detailed investigations are needed to identify the contribution of individual metabolites to AhR activation. This is an innovative suggestion to study in vitro the AhR modulation caused by the human intestinal metabolism.GutTransit Projec

Sucralose and maltodextrin affect differently the gut microbiota of healthy individuals and IBD patients

editorial reviewedIntestinal fibrosis is a long–term complication of inflammatory bowel diseases (IBD). Changes in microbial populations have been linked with the onset of fibrosis and some food additives are known to promote intestinal inflammation facilitating fibrosis induction. Most of these studies have been performed using murine models or healthy donors while the effects of food additives on intestinal microbiota of patients suffering from IBD is less understood. The aim of this work was therefore to determine how food additives affect intestinal microbiota of both healthy and “IBD” donors. Two food additives, sucralose (SUC) and maltodextrin (MDX), were tested in a short–term (72h) in vitro model of the human intestinal microbiota. Three groups of donors were investigated: healthy persons (H), patients in remission of IBD (R) and patients with an active period of IBD (A). Short-chain fatty acid production was assessed using SPME-GC/MS while the evolution of microbial populations positively or negatively correlated with health, inflammation and/or fibrosis was assessed using qPCR. MDX and SUC increased propionate and butyrate production in H and R donors. In addition, MDX increased butyrate in A donors and decreased the butyrate–producer genus Roseburia in H and R donors. Both, SUC and MDX decreased the beneficial bacteria F. prausnitzii in A donors. Moreover, in R and A donors, SUC and MDX decreased A. muciniphila. MDX promoted the growth of Enterococcus in H and R groups and Streptococcus in the three groups of donors, both genus being associated with intestinal inflammation. SUC induced increases of Escherichia/Shigella in H and Enterococcus in H and R groups. Ruminococcus, correlated with higher risk of fibrosis, was increased in the three groups of donors treated with MDX while SUC increased Ruminococcus only in IBD donors. Oscillospira, correlated with reduced risk of fibrosis, was decreased in the three groups of donors with MDX and in H and A donors with SUC. This study demonstrates how strongly the human microbiota can be affected by some food additives. In addition, to our knowledge, this is the first human in vitro study focusing on the impact of food additives on microbiota of IBD patients

Monitoring of oxolinic acid residues in tilapia flesh (Oreochromis niloticus) using a microbiological screening technique and an LC-UV confirmatory method

peer reviewe

Human Adult Microbiota in a Static Colon Model: AhR Transcriptional Activity at the Crossroads of Host–Microbe Interaction

peer reviewedFunctional symbiotic intestinal microbiota regulates immune defense and the metabolic processing of xenobiotics in the host. The aryl hydrocarbon receptor (AhR) is one of the transcription factors mediating host–microbe interaction. An in vitro static simulation of the human colon was used in this work to analyze the evolution of bacterial populations, the microbial metabolic output, and the potential induction of AhR transcriptional activity in healthy gut ecosystems. Fifteen target taxa were explored by qPCR, and the metabolic content was chromatographically profiled using SPME-GC-MS and UPLC-FLD to quantify short-chain fatty acids (SCFA) and biogenic amines, respectively. Over 72 h of fermentation, the microbiota and most produced metabolites remained stable. Fermentation supernatant induced AhR transcription in two of the three reporter gene cell lines (T47D, HepG2, HT29) evaluated. Mammary and intestinal cells were more sensitive to microbiota metabolic production, which showed greater AhR agonism than the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) used as a positive control. Some of the SCFA and biogenic amines identified could crucially contribute to the potent AhR induction of the fermentation products. As a fundamental pathway mediating human intestinal homeostasis and as a sensor for several microbial metabolites, AhR activation might be a useful endpoint to include in studies of the gut microbiota.GutTransit Project (Convention N  8225, Pôle–N  27), Wagralim, Wallonie, Belgiu

Camellia sinensis extract delays microbiological and oxidative changes in striped catfish fillets during frozen storage

peer reviewedThis study investigated the effects of tea leaf (Camellia sinensis) extract on the quality of striped catfish (Pangasianodon hypophthalmus) fillets during 18-months of frozen storage (-20 ± 2 °C). Fillet samples were submitted to the treatments Control (cold tap water), CS 7.63 (C. sinensis extract solution 7.63 µg/mL) and CS 625 (C. sinensis extract 625 µg/mL) and stored for 18 months, with collections performed at 0, 1, 3, 6, 9, 12 and 18 months. Total viable count, physicochemical parameters (water holding capacity, total volatile basic nitrogen, peroxide value, thiobarbituric acid reactive substances, moisture and pH), sensory properties and color measurement were evaluated. Results showed that fillets treated with C.a sinensis extracts slightly reduced lipid oxidation, inhibited bacterial growth and improved sensory properties compared to untreated samples, without causing significant changes in the other quality indicators. The findings indicated that the green tea leaf extract immersion treatments, contributed to the improved quality preservation of striped catfish fillets during frozen storage

Preservation practices and safety of fresh shrimp (Penaeus notialis) sold in Beninese markets

peer reviewedAbstractThe microbiological characteristics of fresh shrimps during storage in ice (FSPI) (1–4.5 °C) and at ambient temperature (FSKAT) (27.5–29.5 °C) was evaluated in Beninese selling market conditions to assess hygiene and shrimp safety in artisanal preservation practices. Furthermore, samples of FSPI and FSKAT sold at the retail markets were collected and analyzed using bacteriological and physicochemical methods. The acceptable limits for aerobic mesophilic bacteria (AMB) [7.0 Log10 (CFU/g)] and trimethylamine (TMA) (5 mg/100 g) were exceeded after 12 days (FSPI) and 9 h (FSKAT). Most market samples (75% FSPI, 92% FSKAT) were non-compliant with the acceptable limit for AMB. The maximal limits specified were exceeded regarding Enterobacteriaceae, E. coli, and Salmonella, up to 75%, 92%, and 42%, respectively (FSKAT) and 33%, 67%, and 75% (FSPI). About 33% (FSPI) and 58% (FSKAT) samples were non-compliant with the TMA limit. All the samples were within the acceptable limits of histamine and tyramine. However, training stakeholders in good handling and hygienic practices is necessary

Use of an in vitro gastrointestinal model to evaluate the potential impact of a vegetal extract on human intestinal health

editorial reviewedThere are numerous medicinal plants and fruits traditionally used to treat gastrointestinal disorders. However, the effects caused by these vegetal products on the intestinal microbial populations are poorly understood. METHODS: An in vitro simulator of human digestion (SHIME®) was used to analyze the intestinal effects of two weeks of treatment with three increasing doses of a vegetal extract. Gut microbiota community and metabolites were studied on ascending (AC), transverse (TC), and descending (DC) colons using qPCR and SPME-GC/MS methods, respectively. RESULTS: A significant increase of acetic acid in TC, and of butyrate in all colons were observed by the end of treatment, while propionate levels remained unchanged. On 11 targeted microbial populations, most decreased in DC during the treatment, and Bacteroidetes decreased in all colon compartments, while Firmicutes increased. Bifidobacterium increased in AC even two weeks after completing the treatment. Akkermansia muciniphila increased in TC and DC following treatment with the higher doses. During the two weeks after completing the treatment, Bacteroides-Prevotella populations significantly increased in TC and DC regions, probably as a residual effect induced by the vegetal extract. Overall, the studied vegetal extract increased health-promoting bacteria which could have a beneficial impact on gastrointestinal health and gut barrier.GutTansit Projec

Impact Assessment of vB_KpnP_K1-ULIP33 Bacteriophage on the Human Gut Microbiota Using a Dynamic In Vitro Model

peer reviewedNew control methods are needed to counter antimicrobial resistances and the use of bacteriophages as an alternative treatment seems promising. To that end, the effect of the phage vB_KpnP_K1-ULIP33, whose host is the hypervirulent Klebsiella pneumoniae SA12 (ST23 and capsular type K1), was assessed on intestinal microbiota, using an in vitro model: the SHIME® system (Simulator of the Human Intestinal Microbial Ecosystem). After stabilization of the system, the phage was inoculated for 7 days and its persistence in the different colons was studied until its disappearance from the system. The concentration of short chain fatty acids in the colons showed good colonization of the bioreactors by the microbiota and no significant effect related to the phage treatment. Diversity (α and β), the relative abundance of bacteria, and qPCR analysis targeting different genera of interest showed no significant variation following phage administration. Even if further in vitro studies are needed to assess the efficacy of this phage against its bacterial host within the human intestinal ecosystem, the phage ULIP33 exerted no significant change on the global colonic microbiota

The efficacy and effect on gut microbiota of an aflatoxin binder and a fumonisin esterase using an in vitro simulator of the human intestinal microbial ecosystem (SHIME®)

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