Unveiling the influence of a probiotic combination of Heyndrickxia coagulans and Lacticaseibacillus casei on healthy human gut microbiota using the TripleSHIME® system.

Probiotics are host-friendly microorganisms that can have important health benefits in the human gut microbiota as dietary supplements. Maintaining a healthy gut microbial balance relies on the intricate interplay among the intestinal microbiota, metabolic activities, and the host's immune response. This study aims to explore if a mixture of Heyndrickxia coagulans [ATB-BCS-042] and Lacticaseibacillus casei [THT-030-401] promotes in vitro this balance in representative gut microbiota from healthy individuals using the Triple-SHIME® (Simulation of the Human Intestinal Microbial Ecosystem). Metataxonomic analysis of the intestinal microbes revealed that the probiotic mix was not causing important disruptions in the biodiversity or microbial composition of the three simulated microbiota. However, some targeted populations analyzed by qPCR were found to be disrupted at the end of the probiotic treatment or after one week of washout. Populations such as Cluster IV, Cluster XVIa, and Roseburia spp., were increased indicating a potential gut health-promoting butyrogenic effect of the probiotic supplementation. In two of the systems, bifidogenic effects were observed, while in the third, the treatment caused a decrease in bifidobacteria. For the health-detrimental biomarker Escherichia-Shigella, a mild decrease in all systems was observed in the proximal colon sections, but these genera were highly increased in the distal colon sections. By the end of the washout, Bacteroides-Prevotella was found consistently boosted, which could have inflammatory consequences in the intestinal context. Although the probiotics had minimal influence on most quantified metabolites, ammonia consistently decreased after one week of daily probiotic supplementation. In reporter gene assays, aryl hydrocarbon receptor (AhR) activation was favored by the metabolic output obtained from post-treatment periods. Exposure of a human intestinal cell model to fermentation supernatant obtained after probiotic supplementation induced a trend to decrease the mRNA expression of immunomodulatory cytokines (IL-6, IL-8). Overall, with some exceptions, a positive impact of H. coagulans and L. casei probiotic mix was observed in the three parallel experiments, despite inter-individual differences. This study might serve as an in vitro pipeline for the impact assessment of probiotic combinations on the human gut microbiota.

Food additives impair gut microbiota from healthy individuals and IBD patients in a colonic in vitro fermentation model.

Intestinal 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. In this study, we investigated how polysorbate 80, sucralose, titanium dioxide, sodium nitrite and maltodextrin affect the gut microbiota and the metabolic activity in healthy and IBD donors (patients in remission and with a flare of IBD). The Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) with a static (batch) configuration was used to evaluate the effects of food additives on the human intestinal microbiota. Polysorbate 80 and sucralose decreased butyrate-producing bacteria such as Roseburia and Faecalibacterium prausnitzii. Both compounds, also increased bacterial species positively correlated with intestinal inflammation and fibrosis (i.e.: Enterococcus, Veillonella and Mucispirillum schaedleri), especially in donors in remission of IBD. Additionally, polysorbate 80 induced a lower activity of the aryl hydrocarbon receptor (AhR) in the three groups of donors, which can affect the intestinal homeostasis. Maltodextrin, despite increasing short-chain fatty acids production, promoted the growth of Ruminococcus genus, correlated with higher risk of fibrosis, and decreased Oscillospira which is negatively associated with fibrosis. Our findings unveil crucial insights into the potential deleterious effects of polysorbate 80, sucralose and maltodextrin on human gut microbiota in healthy and, to a greater extent, in IBD patients.

M-Batches to Simulate Luminal and Mucosal Human Gut Microbial Ecosystems: A Case Study of the Effects of Coffee and Green Tea.

Gastrointestinal simulations in vitro have only limited approaches to analyze the microbial communities inhabiting the mucosal compartment. Understanding and differentiating gut microbial ecosystems is crucial for a more comprehensive and accurate representation of the gut microbiome and its interactions with the host. Herein is suggested, in a short-term and static set-up (named "M-batches"), the analysis of mucosal and luminal populations of inhabitants of the human colon. After varying several parameters, such as the fermentation volume and the fecal inoculum (single or pool), only minor differences in microbial composition and metabolic production were identified. However, the pool created with feces from five donors and cultivated in a smaller volume (300 mL) seemed to provide a more stable luminal ecosystem. The study of commercially available coffee and green tea in the M-batches suggested some positive effects of these worldwide known beverages, including the increase in butyrate-producing bacteria and lactobacilli populations. We hope that this novel strategy can contribute to future advances in the study of intestinal ecosystems and host-microbe relationships and help elucidate roles of the microbiome in health and disease.

Butyrogenic, bifidogenic and slight anti-inflammatory effects of a green kiwifruit powder (Kiwi FFG®) in a human gastrointestinal model simulating mild constipation.

Green kiwi (Actinidia deliciosa var. Hayward) is a fruit with important nutritional attributes and traditional use as a laxative. In this work, we studied in vitro the colonic fermentation of a standardized green kiwifruit powder (Kiwi FFG®) using representative intestinal microbial content of mildly constipated women. Static (batch) and dynamic configurations of the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) were used to estimate the impact of Kiwi FFG® in the human gut. Analysis of metabolites revealed a significant butyrogenic effect of the kiwifruit powder and, consistently, butyrate-producing bacterial populations (i.e., Faecalibacterium prausnitzii, Cluster IV, Roseburia spp.) were greatly increased in the dynamic gastrointestinal model. Bifidobacterium spp. was also found boosted in the microflora of ascending and transverse colon sections, and a significant rise of Akkermansia muciniphila was identified in the transverse colon. Reporter gene assays using human intestinal cells (HT-29) showed that kiwifruit fermentation metabolites activate the aryl hydrocarbon receptor (AhR) transcriptional pathway, which is an important regulator of intestinal homeostasis and immunity. Moreover, modulation in the production of human interleukins (IL-6 and IL-10) in Caco-2 cells suggested a potential mild anti-inflammatory effect of the kiwifruit powder and its gut microbiota-derived metabolites. Our results suggested a potential health benefit of Kiwi FFG® in the gut microbiota, particularly in the context of constipated people.

Effects of Aflatoxins and Fumonisins, Alone or in Combination, on Performance, Health, and Safety of Food Products of Broiler Chickens, and Mitigation Efficacy of Bentonite and Fumonisin Esterase.

The current study evaluated the effects of feeding diets contaminated with aflatoxin B1 (AFB1), fumonisins (FBs), or both on the performance and health of broiler chickens and the safety of their food products as well as the efficacy of bentonite and fumonisin esterase to mitigate the effects of these mycotoxins under conditions representative for sub-Saharan Africa (SSA). Four hundred one-day-old Cobb 500 broiler chickens were randomly assigned to 20 treatments with either a control diet, a diet with moderate AFB1 (60 µg/kg feed) or high AFB1 (220 µg/kg feed), or FBs (17,430 µg FB1+FB2/kg feed), alone or in combination, a diet containing AFB1 (either 60 or 220 µg/kg) and/or FBs (17,430 µg FB1+FB2/kg) and bentonite or fumonisin esterase or both, or a diet with bentonite or fumonisin esterase only. The experimental diets were given to the birds from day 1 to day 35 of age, and the effects of the different treatments on production performance were assessed by feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR). Possible health effects were evaluated through blood biochemistry, organ weights, mortality, liver gross pathological changes, and vaccine response. Residues of aflatoxins (AFB1, B2, G1, G2, M1 and M2) were determined in plasma, muscle, and liver tissues using validated UHPLC-MS/MS methods. The results obtained indicated that broiler chickens fed high AFB1 alone had poor FCR when compared to a diet with both high AFB1 and FBs (p = 0.0063). Serum total protein and albumin from birds fed FBs only or in combination with moderate or high AFB1 or detoxifiers increased when compared to the control (p < 0.05). Liver gross pathological changes were more pronounced in birds fed contaminated diets when compared to birds fed the control or diets supplemented with mycotoxin detoxifiers. The relative weight of the heart was significantly higher in birds fed high AFB1 and FBs when compared to the control or high AFB1 only diets (p < 0.05), indicating interactions between the mycotoxins. Inclusion of bentonite in AFB1-contaminated diets offered a protective effect on the change in weights of the liver, heart and spleen (p < 0.05). Residues of AFB1 were detected above the limit of quantification (max: 0.12 ± 0.03 µg/kg) in liver samples only, from birds fed a diet with high AFB1 only or with FBs or the detoxifiers. Supplementing bentonite into these AFB1-contaminated diets reduced the levels of the liver AFB1 residues by up to 50%. Bentonite or fumonisin esterase, alone, did not affect the performance and health of broiler chickens. Thus, at the doses tested, both detoxifiers were safe and efficient for use as valid means of counteracting the negative effects of AFB1 and FBs as well as transfer of AFB1 to food products (liver) of broiler chickens.

Evaluation of Four Multispecies Probiotic Cocktails in a Human Colonic Fermentation Model.

Bacteriotherapy represents an attractive approach for both prophylaxis and treatment of human diseases. However, combining probiotic bacteria in "cocktails" is underexplored, despite its potential as an alternative multi-target therapy. Herein, three-strain probiotic mixtures containing different combinations of Bacillus (Bc.) coagulans [ATB-BCS-042], Levilactobacillus (Lv.) brevis [THT 0303101], Lacticaseibacillus (Lc.) paracasei [THT 031901], Bacillus subtilis subsp. natto [ATB-BSN-049], Enterococcus faecium [ATB-EFM-030], and Bifidobacterium (Bf.) animalis subsp. lactis [THT 010802] were prepared. Four cocktails (PA: Bc. coagulans + Lv. brevis + Lc. paracasei, PB: Bc. subtilis subsp. natto + Lv. brevis + Lc. paracasei, PC: E. faecium + Lv. brevis + Lc. paracasei, PD: Bc. coagulans + Lv. brevis + Bf. animalis subsp. lactis) were tested using a short-term (72 h) simulation of the human colonic microbiota in a final dose of 6 × 109 CFU. All these probiotic mixtures significantly increased butyrate production compared to the parallel control experiment. PA and PB promoted a bifidogenic effect and facilitated lactobacilli colonization. Furthermore, reporter gene assays using the AhR_HT29-Lucia cell line revealed that fermentation supernatants from PA and PB notably induced AhR transactivity. Subsequent examination of the metabolic outputs of PA and PB in intestinal epithelial models using cell culture inserts suggested no significant impact on the transepithelial electrical resistance (TEER). Assessment of the expression of proinflammatory and anti-inflammatory cytokines, as well as AhR-related target genes in the Caco-2 cell monolayers indicated that PB's metabolic output upregulated most of the measured endpoints. This in vitro investigation evaluated the potential impact of four multispecies probiotic mixtures in the human colonic microbiota and identified a promising formulation comprising a combination of Bc. subtilis subsp. natto, Lv. brevis, and Lc. paracasei as a promising formulation for further study.

Phage Targeting Neonatal Meningitis E. coli K1 In Vitro in the Intestinal Microbiota of Pregnant Donors and Impact on Bacterial Populations.

Escherichia coli K1 is a leading cause of neonatal meningitis. The asymptomatic carriage of these strains in the maternal intestinal microbiota constitutes a risk of vertical transmission to the infant at birth. The aim of this work was to evaluate the efficacy of phage therapy against E. coli K1 in an intestinal environment and its impact on the intestinal microbiota. For this purpose, three independent experiments were conducted on the SHIME® system, the first one with only the phage vB_EcoP_K1_ULINTec4, the second experiment with only E. coli K1 and the last experiment with both E. coli K1 and the phage. Microbiota monitoring was performed using metagenetics, qPCR, SCFA analysis and the induction of AhR. The results showed that phage vB_EcoP_K1_ULINTec4, inoculated alone, was progressively cleared by the system and replicates in the presence of its host. E. coli K1 persisted in the microbiota but decreased in the presence of the phage. The impact on the microbiota was revealed to be donor dependent, and the bacterial populations were not dramatically affected by vB_K1_ULINTec4, either alone or with its host. In conclusion, these experiments showed that the phage was able to infect the E. coli K1 in the system but did not completely eliminate the bacterial load.

In Vitro Effect on Piglet Gut Microbiota and In Vivo Assessment of Newly Isolated Bacteriophages against F18 Enterotoxigenic Escherichia coli (ETEC).

Enterotoxigenic Escherichia coli (ETEC) causing post-weaning diarrhea (PWD) in piglets have a detrimental impact on animal health and economy in pig production. ETEC strains can adhere to the host's small intestinal epithelial cells using fimbriae such as F4 and F18. Phage therapy could represent an interesting alternative to antimicrobial resistance against ETEC infections. In this study, four bacteriophages, named vB_EcoS_ULIM2, vB_EcoM_ULIM3, vB_EcoM_ULIM8 and vB_EcoM_ULIM9, were isolated against an O8:F18 E. coli strain (A-I-210) and selected based on their host range. These phages were characterized in vitro, showing a lytic activity over a pH (4-10) and temperature (25-45 °C) range. According to genomic analysis, these bacteriophages belong to the Caudoviricetes class. No gene related to lysogeny was identified. The in vivo Galleria mellonella larvae model suggested the therapeutic potential of one selected phage, vB_EcoS_ULIM2, with a statistically significant increase in survival compared to non-treated larvae. To assess the effect of this phage on the piglet gut microbiota, vB_EcoS_ULIM2 was inoculated in a static model simulating the piglet intestinal microbial ecosystem for 72 h. This study shows that this phage replicates efficiently both in vitro and in vivo in a Galleria mellonella model and reveals the safety of the phage-based treatment on the piglet microbiota.

Psidium guajava L.- dichloromethane and ethyl acetate fractions ameliorate striped catfish (Pangasianodon hypophthalmus) status via immune response, inflammatory, and apoptosis pathways.

Psidium guajava L. is known to possess immune-modulatory properties in humans and other mammals. Although the positive effects of P. guajava-based diets on the immunological status have been shown for some fish species, the underlying molecular mechanisms of its protective effects remain to be investigated. The aims of this study were to evaluate the immune-modulatory effects of two guava fractions from dichloromethane (CC) and ethyl acetate (EA) on striped catfish with in vitro and in vivo experiments. Striped catfish head kidney leukocytes were stimulated with 40, 20, 10 and 0 µg/ml of each extract fraction, and the immune parameters (ROS, NOS, and lysozyme) were examined at 6 and 24 h post stimulation. A final concentration of each fraction at 40, 10 and 0 µg/fish was then intraperitoneally injected into the fish. After 6, 24, and 72 h of administration, immune parameters as well as the expression of some cytokines related to innate and adaptive immune responses, inflammation, and apoptosis were measured in the head kidney. Results indicated that the humoral (lysozyme) and cellular (ROS and NOS) immune endpoints were regulated differently by CC and EA fractions depending on dose and time in both, in vitro and in vivo experiments. With regards to the in vivo experiment, the CC fraction of the guava extract could significantly enhance the TLRs-MyD88-NF-κB signaling pathway by upregulating its cytokine genes (tlr1, tlr4, myd88, and traf6), following the upregulation of inflammatory (nfκb, tnf, il1ß, and il6) and apoptosis (tp53 and casp8) genes 6 h after injection. Moreover, fish treated with both CC and EA fractions significantly enhanced cytokine gene expression including lys and inos at the later time points - 24 h or 72 h. Our observations suggest that P. guajava fractions modulate the immune, inflammatory, and apoptotic pathways.

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

New 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 ß), 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.

Development of High-Throughput Sample Preparation Procedures for the Quantitative Determination of Aflatoxins in Biological Matrices of Chickens and Cattle Using UHPLC-MS/MS.

Aflatoxins (AFs) frequently contaminate food and animal feeds, especially in (sub) tropical countries. If animals consume contaminated feeds, AFs (mainly aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and their major metabolites aflatoxin M1 (AFM1) and M2 (AFM2)) can be transferred to edible tissues and products, such as eggs, liver and muscle tissue and milk, which ultimately can reach the human food chain. Currently, the European Union has established a maximum level for AFM1 in milk (0.05 µg kg-1). Dietary adsorbents, such as bentonite clay, have been used to reduce AFs exposure in animal husbandry and carry over to edible tissues and products. To investigate the efficacy of adding bentonite clay to animal diets in reducing the concentration of AFB1, AFB2, AFG1, AFG2, and the metabolites AFM1 and AFM2 in animal-derived foods (chicken muscle and liver, eggs, and cattle milk), chicken and cattle plasma and cattle ruminal fluid, a sensitive and selective ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed. High-throughput sample preparation procedures were optimized, allowing the analysis of 96 samples per analytical batch and consisted of a liquid extraction using 1% formic acid in acetonitrile, followed by a further clean-up using QuEChERS (muscle tissue), QuEChERS in combination with Oasis® Ostro (liver tissue), Oasis® Ostro (egg, plasma), and Oasis® PRiME HLB (milk, ruminal fluid). The different procedures were validated in accordance with European guidelines. As a proof-of-concept, the final methods were used to successfully determine AFs concentrations in chicken and cattle samples collected during feeding trials for efficacy and safety evaluation of mycotoxin detoxifiers to protect against AFs as well as their carry-over to animal products.

Efficacy of Bentonite and Fumonisin Esterase in Mitigating the Effects of Aflatoxins and Fumonisins in Two Kenyan Cattle Breeds.

The objective of the study was to investigate the efficacy of bentonite and fumonisin esterase, separately or combined, in mitigating the effects of aflatoxins (AF) and fumonisins (FUM) in Boran and Friesian-Boran crossbreed cattle. These effects were studied by measuring mycotoxins, their metabolites, and biomarkers that relate to animal health, productivity, and food safety. The study was divided into three experiments each lasting for 2 weeks. Cows in experiment 1 received in random order aflatoxin B1 (AFB1) [788 µg/cow/day (69.7 µg/kg dry matter intake (DMI)) for Borans and 2,310 µg/cow/day (154 µg/kg DMI) for crossbreeds], bentonite (60 g/cow/day), or both AFB1 and bentonite. Boran cows in experiment 2 received in random order FUM (12.4 mg/cow/day (1.1 mg/kg DMI)), fumonisin esterase (120 U/cow/day), or both FUM and fumonisin esterase. Boran cows in experiment 3 received in random order AFB1 (952 µg/cow/day (84.2 µg/kg DMI)) + FUM (30.4 mg/cow/day (2.7 mg/kg DMI)), bentonite (60 g/cow/day) + fumonisin esterase (120 U/cow/day), or both AFB1 + FUM and bentonite + fumonisin esterase. Feeding AFB1 and/or FUM contaminated feed with or without the addition of the detoxifiers for 14 days did not affect DMI, milk composition, hematology, and blood biochemical parameters. The addition of bentonite in a diet contaminated with AFB1 led to a decrease in milk aflatoxin M1 (AFM1) concentration of 30% and 43%, with the carry-over subsequently decreasing from 0.35% to 0.20% and 0.08% to 0.06% for crosses and Borans, respectively. No significant change was observed in the sphinganine/sphingosine (Sa/So) ratio following feeding with FUM alone or in combination with fumonisin esterase; however, the ability of fumonisin esterase to hydrolyze FUM into less toxic fully hydrolyzed FUM and partially hydrolyzed FUM was evident in the rumen fluid and feces. These results indicate bentonite was effective in decreasing AFM1 concentration in milk, and AFB1 and AFM1 in plasma, while fumonisin esterase can convert FUM into less toxic metabolites and can be a suitable addition to feed cocontaminated with AFB1 and FUM.

Maximizing Laboratory Production of Aflatoxins and Fumonisins for Use in Experimental Animal Feeds.

Warm and humid climatic conditions coupled with poor agricultural practices in sub-Saharan Africa favor the contamination of food and feed by Aspergillus flavus and Fusarium verticillioides fungi, which subsequently may produce aflatoxins (AFs) and fumonisins (FBs), respectively. The growth of fungi and the production of mycotoxins are influenced by physical (temperature, pH, water activity, light and aeration), nutritional, and biological factors. This study aimed at optimizing the conditions for the laboratory production of large quantities of AFs and FBs for use in the animal experiments. A. flavus and F. verticillioides strains, previously isolated from maize in Kenya, were used. Levels of AFB1 and total FBs (FB1, FB2, and FB3) in different growth substrates were screened using ELISA methods. Maize kernels inoculated with three different strains of A. flavus simultaneously and incubated at 29 °C for 21 days had the highest AFB1 level of 12,550 ± 3397 µg/kg of substrate. The highest level of total FBs (386,533 ± 153,302 µg/kg of substrate) was detected in cracked maize inoculated with three different strains of F. verticillioides and incubated for 21 days at temperatures of 22-25 °C in a growth chamber fitted with yellow light. These two methods are recommended for the mass production of AFB1 and FBs for animal feeding trials.

Assessment of heterocyclic aromatic amines contents in flamed and braised chicken in Burkina Faso.

The nutritional status of meat is tarnished by its association with the induced cooking contaminants. The aim of this study was to assess the heterocyclic aromatic amines profile and contents in processed chicken in Burkina Faso. Eight polar and apolar heterocyclic aromatic amines (HAAs) including 2-mino-3-methylimidazo[4,5-f]quinolone (IQ), 3-amino-1,4-dimethyl-5H-pyrido[4, 3-b]indole (Trp-P1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P2), 2-mino-9H-pyrido-[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4, 5- ]pyridine (PhIP), 2-amino-3-methyl-9H-pyrido[2,3-b] indole (MeAαC), 2-amino-3,4,8-rimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) and 2-amino-3,8-imethylimidazo[4,5-]quinoxaline (MeIQx) were screened by high performance liquid chromatography from 29 samples of flamed chicken and 66 samples of braised chicken collected in Ouagadougou city. Apolar HAAs and polar HAAs were respectively 12 and 3 times more abundant in flamed chickens (32.66±10 and 3.48±10.39 ng/g, respectively) than in braised chickens (2.70±9.67 and 0.92 ng/g, respectively). The maximum levels of AαC were in the same proportions in flamed (12.01 ng/g) and braised chickens (14.13 ng/g). Flamed chicken had the highest Trp-P1 content (530.31 ng/g). The 4,8-DiMeIQx was not detected in braised chicken. The AαCs were more abundant in flamed than in braised chicken. The profile and the contents of the HAAs in processed chicken are related to cooking methods. Because of the high variability observed on the obtained concentrations, investigations on the contents of precursors in raw chicken, the effect of marinating ingredients on the formation of HAAs are needed.

Polycyclic aromatic hydrocarbons in spices and dried herbs and associated risk for the Belgian population.

A total of 120 spices and herbs bought on the Belgian market have been analysed for occurrence of the four EU regulated polycyclic aromatic hydrocarbons (ΣPAH4). Samples were sorted in three groups according to their use: traditional spices, exotic spices, and herbs. Benzo[a]pyrene has been detected in 56% of samples, while ΣPAH4 were found in 96% of samples. ΣPAH4 were evenly distributed among the three groups with a median content of 7.2 for traditional spices, 5.5 for exotic spices and 6.0 µg kg-1 for herbs. According to the EU legislation, three samples were exceeding maximal limits, with a maximum ΣPAH4 content of 164 µg kg-1. The ΣPAH4 dietary intake has been estimated at 1.4 and 27.8 ng day-1 for average and high consumption, respectively. The risk for the consumer was evaluated by using the margin of exposure (MOE). In all cases, MOE were >20 000, indicating a low concern for the population.

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

Functional 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.

Integrated biomarker response to assess the effects of pesticide residues on Nile Tilapia in aquatic ecosystems contaminated by cotton-field effluents.

An in-situ study combined with an integrated biomarker response was used to evaluate the impact of agricultural effluents in the physiological responses of Nile tilapia reared in cages and enclosures of water reservoirs in North Benin. Fish were distributed in fish farming systems at two sites: Songhai located outside the cotton basin and Batran located in the most productive commune. They were sampled for blood and organs before (BST), during (DST) and after (AST) pesticide treatment. Pesticide residues were analysed in water, sediments and fish muscles. Several biomarkers were investigated related to the immune (peroxidase, lysozyme and complement activities, superoxide anion production) and reproductive (sex steroids and vitellogenin levels) responses as well as neurotoxicity (cholinesterase activity) and tissue alterations. Biomarkers were assessed and analysed via the integrated biomarker response (IBR). The results showed that Batran water reservoir was a more harmful ecosystem for fish than Songhai one, especially by depressing some immune and reproductive functions in relation to a higher-level of pesticide contamination. They also demonstrated that the contact of fish to sediments in enclosures aggravated the pesticide burden on fish. Therefore, using males as bioindicators would improve the sensitivity of the used biomarkers since males seemed more affected than females especially due to pesticide estrogenic induction impacting their reproductive system.

Performances of the barrel kiln used in cottage industry for fish processing and effects on physicochemical characteristics and safety of smoked fish products.

BACKGROUND: In the traditional food sector, the smoking process and smoking-drying process are widely used to increase the shelf-life of seafood products. The smoking process and smoking-drying process are mainly performed using barrel kiln and wood as fuel in many West African countries. The present study evaluated the performances of the barrel kiln and its effects on physicochemical characteristics and safety of smoked fish (SF) and smoked-dried fish (SDF). Twelve follow-ups were conducted with three experimental processors and 24 samples of fish collected at different steps of processing were analyzed in a laboratory using standard methods. RESULTS: The extreme values of combustion temperature recorded during the smoking process (456.4 °C) and smoking-drying process (482.8 °C) were higher than 450 °C, the temperature at which wood pyrolysis generates polycyclic aromatic hydrocarbons (PAHs). Smoked fish were highly contaminated with PAHs, and showed maximal levels of benzo[a]pyrene (52.7 µg kg-1 ) and PAH4 (i.e. sum of benzo[a]pyrene, chrysene, benzo[b]fluoranthene and benz[a]anthracene) (290.9 µg kg-1 ) exceeding the European Union limits by about 25-fold. After smoking of Scomber scombrus and smoking-drying of Cypselurus cyanopterus, no significant differences were recorded for lipid, protein and biogenic amine contents between fresh and processed fish, even if the histamine content of both fish exceeded the limit fixed by the European Union regulation. CONCLUSION: The results obtained in the present study showed that smoked fish and smoked-dried fish produced using barrel kiln and wood fuel are highly contaminated by PAHs. Therefore, there is a need to improve the preservation practices of raw fish and smoking conditions to limit the contamination of end-products by PAHs known to be carcinogenic components for humans and to ensure consumer safety. © 2021 Society of Chemical Industry.

Profile occurrences and in vitro effects of toxic organic pollutants in metal shredding facilities in Wallonia (Belgium).

End-of-life vehicles and e-waste contain several hazardous substances that can contaminate the environment during treatment processes. Occurrences and adverse effects of toxic organic pollutants emitted from 3 shredder plants located in Wallonia, Belgium, were investigated by chemical and biological analyses of fluff, dust, and scrubbing sludge sampled in 2019. Site 1 showed the highest concentrations of chlorinated compounds in sludge with 7.5 ng/g polychlorinated dibenzo-dioxins/furans and 84.5 µg/g estimated total polychlorinated biphenyls, while site 3 led the brominated flame retardant levels in dust (53.4 µg/g). The level of polycyclic aromatic hydrocarbons was highest in the sludge samples, 78 and 71 µg/g for sites 2 and 3, respectively. The samples induced significant dioxin-like activities in murine and human cells at concentrations of around 0.01-0.1 and 0.5-1 ng (sample) per ml (medium), respectively, with the efficacy similar to 2,3,7,8-tetrachlorodibenzodioxin and EC50 values of around 1 and 10 ng/ml. The samples also displayed high estrogenic activities, already at 1 ng/ml, and several induced a response as efficient as 17ß-estradiol, albeit a low androgenic activity. Shredder workers were estimated to be highly exposed to dioxin-like compounds through dust ingestion and dermal absorption, which is of concern.

Chemical hazards in smoked meat and fish.

This review aims to give an insight into the main hazards currently found in smoked meat and fish products. Literature research was carried out on international databases such as Access to Global Online Research in Agriculture (AGORA) database, Science direct, and Google scholar to collect and select 92 relevant publications included in this review. The smoking process was described and five hazards mostly found in smoked fish and meat were presented. The heat-induced compounds such as polycyclic aromatic hydrocarbons, heterocyclic amines, and nitrosamines were found in smoked fish and meat. Other hazards such as biogenic amines and heavy metals were also present in smoked fish and meat. The levels of these hazards reported from the literature exceeded the maximal limits of European Union. A brief description of risk assessment methodology applicable to such toxic compounds and risk assessment examples was also presented in this review. As most of the hazards reported in this review are toxic and even carcinogenic to humans, actions should be addressed to reduce their presence in food to protect consumer health and to prevent public health issue.