Characteristics of Lactococcus petauri GB97 lysate isolated from porcine feces and its in vitro and in vivo effects on inflammation, intestinal barrier function, and gut microbiota composition in mice

IMPORTANCE

Weaning is a crucial step in piglet management to improve pork production. During the weaning phase, disruption of epithelial barrier function and intestinal inflammation can lead to decreased absorption of nutrients and diarrhea. Therefore, maintaining a healthy intestine, epithelial barrier function, and gut microbiota composition in this crucial phase is strategic for optimal weaning in pigs. We isolated a lysate of Lactococcus petauri GB97 (LPL97) from healthy porcine feces and evaluated its anti-inflammatory activities, barrier integrity, and gut microbial changes in LPS-induced murine macrophages and DSS-induced colitis mice. We found that LPL97 regulated the immune response by downregulating the TLR4/NF-κB/MAPK signaling pathway both in vitro and in vivo. Furthermore, LPL97 alleviated the disruption of intestinal epithelial integrity and gut microbiota dysbiosis in colitis mice. This study indicates that LPL97 has the potential to be developed as an alternative feed additive to antibiotics for the swine industry.

Safety assessment of surfactin-producing Bacillus strains and their lipopeptides extracts in vitro and in vivo

Beneficial Bacillus strains can be administered to livestock as probiotics to improve animal health. Cyclic lipopeptides produced by Bacillus such as surfactins may be responsible for some of the beneficial effects due to their anti-inflammatory and immunomodulatory activity. The aim of the present study was to isolate and evaluate the biocompatibility of native Bacillus spp. strains and their surfactin-like lipopeptides in vitro and in vivo to determine their potential to be used on animals. Biocompatibility of endospore suspensions (10⁸  UFC/mL), and different dilutions (1:10; 1:50; 1:100; 1:500, and 1:1000) of Bacillus lipopeptide extracts containing surfactin was tested on Caco-2 cells by microculture tetrazolium-based colorimetric assay. Genotoxicity was tested on BALB/c mice (n = 6) administered 0.2 mL of endospore suspensions by the bone marrow erythrocyte micronuclei assay. All the isolates tested produced between 26.96 and 239.97 µg mL^{- 1} of surfactin. The lipopeptide extract (LPE) from isolate MFF1.11 demonstrated significant cytotoxicity in vitro. In contrast, LPE from MFF 2.2; MFF 2.7, TL1.11, TL 2.5, and TC12 had no cytotoxic effect (V% > 70%) on Caco-2 cells, not affecting cell viability signifficantly in most treatments. Similarly, none of the endospore suspensions affected cell viability (V% > 80%). Likewise, endospores did not cause genotoxicity on BALB/c mice. This study was elementary as a first step for a new line of research, since it allowed us to choose the safest isolates to keep working on the search of new potentially probiotic strains destined to production animals to improve their performance and health.

The Anti- and Pro-Tumorigenic Role of Microbiota and Its Role in Anticancer Therapeutic Strategies

Human gut microbiota physiologically and actively participates as a symbiont to a wide number of fundamental biological processes, such as absorption and metabolism of nutrients, regulation of immune response and inflammation; gut microbiota plays also an antitumor role. However, dysbiosis, resulting from a number of different situations-dysmicrobism, infections, drug intake, age, diet-as well as from their multiple combinations, may lead to tumorigenesis and is associated with approximately 20% of all cancers. In a diagnostic, prognostic, therapeutic, and epidemiological perspective, it is clear that the bifaceted role of microbiota needs to be thoroughly studied and better understood. Here, we discuss the anti- and pro-tumorigenic potential of gut and other microbiota districts along with the causes that may change commensal bacteria from friend to foes.

Comparative Evaluation of the Capacity of Commercial and Autochthonous Saccharomyces cerevisiae Strains to Remove Ochratoxin A from Natural and Synthetic Grape Juices

In this paper, we assessed the ability of two strains of Saccharomyces cerevisiae, in viable and dead forms, to remove ochratoxin A (OTA) from an artificially contaminated synthetic grape juice medium (SGM) (10 µg OTA/L) and a naturally contaminated grape juice (6.64 µg OTA/L). The first strain, named Levulin FB, is a commercial yeast used in making wine. The second, named SC5, is an autochthonous strain isolated from table grapes. OTA concentrations in juices before and after their contact with yeast cells were assessed. A significant decrease in OTA level (p < 0.05) in the SGM medium and in the natural grape juice was observed after 1 h of adding yeast cells (20 g/L) in viable and heat-treated forms. It was inferred that the dead forms of the two strains were more able to eliminate OTA than their viable forms in both media. This study demonstrates the potential application of an autochthonous yeast for the natural decontamination of grape juice from fungal toxins.

A Systematic Review of the Efficacy of Interventions to Control Aflatoxins in the Dairy Production Chain—Feed Production and Animal Feeding Interventions

The study presents a systematic review of published scientific articles investigating the effects of interventions aiming at aflatoxin reduction at the feed production and animal feeding phases of the milk value chain in order to identify the recent scientific trends and summarize the main findings available in the literature. The review strategy was designed based on the guidance of the systematic review and knowledge synthesis methodology that is applicable in the field of food safety. The Web of Science and EBSCOhost online databases were searched with predefined algorithms. After title and abstract relevance screening and relevance confirmation with full-text screening, 67 studies remained for data extraction, which were included in the review. The most important identified groups of interventions based on their mode of action and place in the technological process are as follows: low-moisture production using preservatives, acidity regulators, adsorbents and various microbiological additives. The results of the listed publications are summarized and compared for all the identified intervention groups. The paper aimed to help feed producers, farmers and relevant stakeholders to get an overview of the most suitable aflatoxin mitigation options, which is extremely important in the near future as climate change will likely be accompanied by elevated mycotoxin levels.

Effects of aflatoxin B1 and monensin interaction on liver and intestine of poultry – influence of a biological additive (Pichia kudriavzevii RC001)

The aim of this study was to evaluate the effects of aflatoxin B1 (AFB1) and monensin (MONS) interaction on the liver and intestinal histological changes in poultry, and the influence of Pichia kudriavzevii RC001. One-day-old commercial line (Ross 308) broilers (n=120) were individually weighed and randomly assigned to 8 treatments (15 broilers/treatment, 5 broilers per cage and 3 replicates/treatment). The experimental diets were: Group 1: basal diet (BD); Group 2: BD + MONS (50 mg/kg); Group 3: BD + P. kudriavzevii RC001 (1 g/kg); Group 4: BD + AFB1 (100 μg/kg); Group 5: BD + MONS + P. kudriavzevii RC001; Group 6: BD + AFB1 + P. kudriavzevii RC001; Group 7: BD + AFB1 + MONS + P. kudriavzevii RC001; Group 8: BD + AFB1 + MONS. When MONS was added, the typical AFB1 macroscopic and microscopic alterations were intensified. The P. kudriavzevii RC001 cytotoxicity and genotoxicity assays with Vero cells and with broiler chicken’s erythrocytes, demonstrated that P. kudriavzevii RC001 neither were non-cytotoxic nor genotoxic. When MONS was added in the presence of P. kudriavzevii RC001, the toxic effect of AFB1 on liver was not prevented. When P. kudriavzevii was present alone, the same prevention of the pathological damage was observed in the intestine of poultry fed with AFB1. The smallest apparent absorption area was obtained when AFB1 and MONS were added in the feed (P<0.05). AFB1 and MONS interaction demonstrated important toxic effects. Although P. kudriavzevii was effective in ameliorating the adverse effects of AFB1 alone on liver pathology and gut morphology, it was not able to diminish the toxic effects of AFB1 in presence of MONS. It suggests that P. kudriavzevii could be used as feed additive or counteracting the toxic effects of AFB1 in poultry production in the absence of MONS.

Probiotic gut-borne Saccharomyces cerevisiae reduces liver toxicity caused by aflatoxins in weanling piglets

The present study was conducted to investigate the aflatoxin B1 (AFB1) liver toxicity and gut histomorphometry after gut borne-Saccharomyces cerevisiae supplementation to AFB1-contaminated piglet diets. Thirty-two male mixed-breed piglets (weaned at 21 days old) were housed in individual pens and allowed to acclimate for 7 days. Animals were randomly assigned to four treatments of 22 days: T1 – low AFB1 levels diet (L, 31.6 μg/kg); T2 – L + S. cerevisiae 1 g/kg; T3 – high AFs levels diet (H, 495 μg/kg); T4 – H + S. cerevisiae 1 g/kg. The addition of probiotic yeast was able to reduce 72% of residual AFB1 present in the liver. The liver histopathology of piglets fed AFB1 showed a typical macroscopic and microscopic pattern of subclinical aflatoxicosis that was prevented by the yeast. Also, the addition of the yeast was able to decrease the alanine-aminotransferase (25.5±0.71 U) and aspartate-aminotransferase (26.5±6.10 U) even showing values lower than the control ones. The apparent absorption area showed the greater surface when the probiotic was present alone compared to the control (T1), whereas when present together with the toxin demonstrated a modulatory effect. The addition of probiotic gut-borne S. cerevisiae in the pig diets was effective in counteracting the toxic effects of harmful AFB1 in livers besides a tendency to improve the histomorphometric parameters and modulating the toxic effect of AFB1 on intestine. These results are promising for the production of feed additives that will be used in animal feed, since the probiotic action and the decontamination of mycotoxins in the same product are complemented.

Toxicological evaluation of a glycan preparation from an enzymatic hydrolysis of Saccharomyces cerevisiae

The aim of this paper was to provide a comprehensive toxicological and safety evaluation of a yeast cell wall preparation (YCWP) for use as an animal feed ingredient. The following toxicological assessments were carried out: the mutagenic activity was tested using the Ames' Test in five Salmonella typhimurium strains; clastogenic activity was investigated using the mammalian micronucleus test in Swiss ICO OF1 (IOPS Caw) mice; genotoxic activity was assessed using the in vitro mammalian chromosomal aberration test in human lymphocytes; acute oral toxicity was tested by administration of a single dose of 2000 mg/kg BW. Eye and skin irritation were assessed in rabbits according to OECD guidelines; skin sensitivity was established in guinea pigs by means of the Buehler test, while acute dermal and inhalation studies in rats were further completed, also according to OECD guidelines. All conducted tests were considered valid under the experimental conditions. No significant mutagenic activity or genotoxic activity was observed, and it was concluded that the test article did not induce any clastogenic effect. YCWP was found to be mildly irritating to the eye, slightly irritating to the skin but was found to be non-sensitizing in the guinea pig. The acute oral, dermal and inhalation studies did not yield any evidence of gross toxicity or pharmacological effects.

Influence of technological procedures on viability, probiotic and anti-mycotoxin properties of Saccharomyces boulardii RC009, and biological safety studies

The objective was to evaluate the technological processing (protection strategies and storage conditions) influence on viability, on probiotic properties and adsorbent aflatoxin B₁ capacity of S. boulardii RC009. Also, the yeast biological safety was evaluated. Lyophilisation (DL) and encapsulation ​+ ​lyophilisation (EL) were conducted. Yeast protected with maltodextrin (M) or WPC stored at 4 ​°C reduced 1 and 2 log the viability, respectively. Yeast protected with M stored at 25 ​°C reduced 1 log after 70 ​d; with WPC the viability significantly reduced 3 log after 30 ​d. Technological processing improved the coaggregation’s capacity with pathogens and DL process allowed the greatest AFB₁ adsorption. S. boulardii 10⁶ ​cells/mL were no toxic to Vero cells (p˂0.05). Saccharomyces boulardii RC009 protected with M or WPC maintained viability after technological processing. It possesses a great capacity for AFB₁ adsorption and probiotic properties and could be considered a candidate with proven safety for functional food products development.

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Commercial refinery syrup was a good substrate for Saccharomyces boulardii growth.

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Maltodextrin and WPC were efficient protectors in ensuring the yeast viability.

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The lyophilised yeast achieved high percentages of AFB1 adsorption.

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Saccharomyces boulardii cells were non-toxic in Vero cells up to 106 ​CFU/mL.

Adverse Effects, Transformation and Channeling of Aflatoxins Into Food Raw Materials in Livestock

Aflatoxins are wide-spread harmful carcinogenic secondary metabolites produced by Aspergillus species, which cause serious feed and food contaminations and affect farm animals deleteriously with acute or chronic manifestations of mycotoxicoses. On farm, both pre-harvest and post-harvest strategies are applied to minimize the risk of aflatoxin contaminations in feeds. The great economic losses attributable to mycotoxin contaminations have initiated a plethora of research projects to develop new, effective technologies to prevent the highly toxic effects of these secondary metabolites on domestic animals and also to block the carry-over of these mycotoxins to humans through the food chain. Among other areas, this review summarizes the latest findings on the effects of silage production technologies and silage microbiota on aflatoxins, and it also discusses the current applications of probiotic organisms and microbial products in feeding technologies. After ingesting contaminated foodstuffs, aflatoxins are metabolized and biotransformed differently in various animals depending on their inherent and acquired physiological properties. These mycotoxins may cause primary aflatoxicoses with versatile, species-specific adverse effects, which are also dependent on the susceptibility of individual animals within a species, and will be a function of the dose and duration of aflatoxin exposures. The transfer of these undesired compounds from contaminated feed into food of animal origin and the aflatoxin residues present in foods become an additional risk to human health, leading to secondary aflatoxicoses. Considering the biological transformation of aflatoxins in livestock, this review summarizes (i) the metabolism of aflatoxins in different animal species, (ii) the deleterious effects of the mycotoxins and their derivatives on the animals, and (iii) the major risks to animal health in terms of the symptoms and consequences of acute or chronic aflatoxicoses, animal welfare and productivity. Furthermore, we traced the transformation and channeling of Aspergillus-derived mycotoxins into food raw materials, particularly in the case of aflatoxin contaminated milk, which represents the major route of human exposure among animal-derived foods. The early and reliable detection of aflatoxins in feed, forage and primary commodities is an increasingly important issue and, therefore, the newly developed, easy-to-use qualitative and quantitative aflatoxin analytical methods are also summarized in the review.

Saccharomyces cerevisiae RC016 modulates the apoptotic pathways in rat livers treated with aflatoxin B1

The aim was to study the effect of probiotic Saccharomyces cerevisiae RC016 on the expression of apoptotic protein Bax, Bcl-2, DR4 and c-FLIP, in liver of rats exposed to aflatoxin B1 (AFB1). Four treatments were applied to inbred male Wistar rats: uncontaminated feed control, S. cerevisiae RC016 control, contaminated feed with 100 μg/kg AFB1 and contaminated feed with 100 μg/kg AFB1 + daily oral dose 108 viable S. cerevisiae RC016 cells. Histological technique and high-resolution light microscopy (HRLM) were performed to the study of tissue morphology, the TUNEL assay was used to determine the apoptosis cellular and the expression of Bax, Bcl-2, DR4 and c-FLIP was determinate through immunohistochemistry. In liver the necrotic lesions observed with AFB1 treatment were reduced with the addition of yeast. The highest apoptotic index (IAp) was found in the yeast control, with AFB1 decrease significantly the IAp, while with the addition of yeast increase the IAp of liver cells. This was confirmed by HRLM. DR4 receptor was not present in any of the treatments. The immunolabeling of c-FLIP showed a statistically significant increase in the treatments with S. cerevisiae. The extrinsic pathway of apoptosis through the FAS-receptors would neither be active in the apoptotic process observed in rat livers in the treatments with yeast. Significant differences between proteins Bax and Bcl-2 and effect of treatments on the immunolabeling of Bax were determinate. The exposure to AFB1 decreased the IAp in the livers; while the addition of the yeast produced a significant statistically increase of IAp. In this study it was determined that the apoptosis in liver would be induced by the intrinsic pathway through Bax. These suggest that the incorporation of the autocrine strain S. cerevisiae RC016 increases the apoptosis in liver, counteracting the adverse effect of aflatoxin B1 and favouring the tissue remodulation.

Beneficial effects of Saccharomyces cerevisiae RC016 in weaned piglets: in vivo and ex vivo analysis

Probiotics represents an alternative to replace antibiotics as growth promoters in animal feed and are able to control enteric bacterial diseases and to improve gut immunity. Saccharomyces cerevisiae RC016 showed previously inhibition/coagregation of pathogens) and mycotoxins adsorbent ability (aflatoxin B₁, ochratoxin A and zearalenone). The aim of this work was to evaluate beneficial properties of S. cerevisiae RC016 in a non-inflammatory in vivo model in weaned piglets and in an intestinal inflammation ex vivo model induced by the mycotoxin deoxynivalenol (DON). Secretory immunoglobulin A (s-IgA) levels, intestinal cytokines, goblet cells and production parameters were evaluated in a pig model. For the in vivo assays, twelve pigs were weaned at 21 days and assigned to two groups: Control (n=6) and Yeast (n=6). Animals received yeast strain for three weeks. After 22 days the small intestine was recovered for determination of goblet cells and s-IgA. For the ex vivo assay, jejunal explants were obtained from 5 weeks old crossbred piglets and treated as follow: (1) control; (2) treated for 3 h with 10 μM DON used as an inflammatory stressor; (3) incubated with 10⁷ cfu/ml yeast strain; (4) pre-incubated 1 h with 10⁷ cfu/ml yeast strain and then treated for 3 h with 10 μM DON. CCL20, interleukin (IL)-1β, IL-8 and IL-22 gene expression was determined by qPCR. Oral administration of S. cerevisiae RC016 increased s-IgA, the number of goblet cells in small intestine and all the growth parameters measured. In the ex vivo model, the cytokine profile studied showed a potential anti-inflammatory effect of the administration of the yeast. In conclusion, S. cerevisiae RC016 is a promising candidate for feed additives formulation to improve animal growth and gut immune system. This yeast strain could be able to improve the gut health through counteracting the weaning-associated intestinal inflammation in piglets.

Aflatoxins and Saccharomyces cerevisiae: yeast modulates the intestinal effect of aflatoxins, while aflatoxin B1 influences yeast ultrastructure

The gastrointestinal tract (GIT) is the main site where absorption of food components takes place and the first system coming into contact with mycotoxins of dietary origin. The aim of this work was to study the effect of probiotic Saccharomyces cerevisiae RC016 on intestinal villi of rats exposed to aflatoxins for 60 days. Moreover, the effect of in vitro aflatoxin B1 (AFB1) exposure on yeast cell ultrastructure was evaluated. Six treatments were applied (n=6) to inbred male Wistar rats: (1) uncontaminated feed control (F); (2) yeast control; (3) F + 40 μg/kg AFB1 + 20 μg/kg aflatoxin G1 (AFG1); (4) F + 100 μg/kg AFB1 + 50 μg/kg AFG1; (5) F + 40 μg/kg AFB1 + 20 μg/kg AFG1 + daily oral dose 108 viable S. cerevisiae cells; and (6) F + 100 μg/kg AFB1 + 50 μg/kg AFG1 + daily oral dose 108 viable S. cerevisiae cells. Morphometric measurements (villus length and width, crypt depth, quantification of goblet cells) were assessed using image analysis. S. cerevisiae RC016 cells were exposed to 20 μg/ml of AFB1 in intestinal solutions or in phosphate buffered saline and cells processed for transmission electron microscopy and high resolution light microscopy studies. Dietary exposure to the yeast did not induce significant differences in villus width but increased villus length and crypt depth. Aflatoxin-contaminated diets induced an increase in villus length, width and crypt depth and a significant decrease in the number of goblet cells which were improved by the addition of S. cerevisiae RC016. A significant increase in the yeast cell diameter was observed when RC016 was exposed to aflatoxins, suggesting this as an advantage since a larger cell would be able to adsorb mycotoxins more efficiently. The ability of this strain to act as probiotic and aflatoxin binder makes it a candidate for the formulation of new additives to improve animal performance.

Bakery by-products based feeds borne-Saccharomyces cerevisiae strains with probiotic and antimycotoxin effects plus antibiotic resistance properties for use in animal production

The aim of this study was to select S. cerevisiae strains able to exert probiotic and antimycotoxin effects plus antibiotics resistance properties for use in animal production. S. cerevisiae LL74 and S. cerevisiae LL83 were isolated from bakery by-products intended for use in animal feed and examined for phenotypic characteristics and nutritional profile. Resistance to antibiotic, tolerance to gastrointestinal conditions, autoaggregation and coaggregation assay, antagonism to animal pathogens and aflatoxin B₁ binding were studied. S. cerevisiae LL74 and S. cerevisiae LL83 showed resistance to all the antibiotics assayed (ampicillin, streptomycin, neomycin, norfloxacin, penicillin G, sulfonamide and trimethoprim). The analysis showed that exposure time to acid pH had a significant impact onto the viable cell counts onto both yeast strains. Presence of bile 0.5% increased significantly the growth of the both yeast strains. Moreover, they were able to tolerate the simulated gastrointestinal conditions assayed. In general, the coaggregation was positive whereas the autoaggregation capacity was not observed. Both strains were able to adsorb AFB₁. In conclusion, selected S. cerevisiae LL74 and S. cerevisiae LL83 have potential application to be used as a biological method in animal feed as antibiotic therapy replacement in, reducing the adverse effects of AFB₁ and giving probiotic properties.

Gut-borne Saccharomyces cerevisiae, a promising candidate for the formulation of feed additives, modulates immune system and gut microbiota

The aim was to evaluate the effect of Saccharomyces cerevisiae RC016 on immune parameters and gut microbiota in healthy mice. Animals received S. cerevisiae RC016 for 10 days. Microbial translocation to liver and changes in some bacterial populations in caecum were determined. Immune stimulation was assessed at gut level (measure of immunoglobulin A (IgA)+ cells and luminal cytokine profile) and by evaluating the activity of peritoneal macrophages. Oral administration of S. cerevisiae RC016 did not induce microbial translocation to liver. Mice that received yeast increased the number of IgA+ cells in their intestines, the phagocytic activity of peritoneal macrophages and decreased tumour necrosis factor alpha (TNF-α) levels in the small intestine with increases of interleukin-10/TNF-αratio. Administration of S. cerevisiae RC016 caused the decline of a logarithmic unit for Enterobacteriaceae counts compared to the control. The immune and gut microbiota modulation observed demonstrates that S. cerevisiae RC016 is a promising candidate for the formulation of feed additives to improve animal productivity. The beneficial in vivo effects observed for the potential probiotic S. cerevisiae RC016 with previously reported mycotoxin-binding properties, demonstrated that this strain could be suitable to be included in a novel product to improve animal productivity, with both probiotic and mycotoxin-binding properties. However, studies in the specific host will be necessary to confirm this potential.

Mycotoxin contamination in laboratory rat feeds and their implications in animal research

Compound feed is particularly vulnerable to multi-mycotoxin contamination. A method for the determination of 12 mycotoxins; enniatins A, A1, B, B1; aflatoxins B1, B2, G1, G2; OTA; ZEA; T-2 and HT-2 by liquid chromatography-tandem mass spectrometry has been developed and applied for the analysis of laboratory rat commercial feeds. The method trueness was checked by recovery assays at three different spiked levels (n = 9). Recoveries ranged from 73% to 112%, and the intra-day and inter-day precision were lower than 9% and 13%, respectively. Limits of quantitation were lower than 15 μg/kg. Twenty-seven laboratory rats feed samples showed multi-contamination by at least three up to six different mycotoxins. ENNs B and B1, followed by ZEA were the most prevalent mycotoxins. T-2, HT-2, and OTA were not detected. ZEA showed the highest concentration levels reaching 492 μg/kg. The results underline the importance of implementing mycotoxin regular surveillance programs for laboratory animal feeds.