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

Comprehensive Metagenomic Analysis of Veterinary Probiotics in Broiler Chickens

Probiotics are widely used in broiler chickens to support the gut microbiome, gut health, and to reduce the amount of antibiotics used. Despite their benefits, there is concern over their ability to carry and spread antimicrobial resistance genes (ARGs), posing a significant public health risk. This study utilized next-generation sequencing to investigate ARGs in probiotics approved for poultry, focusing on their potential to be transferred via mobile genetic elements such as plasmids and phages. We examined the gut microbiome and resistome changes in 60 broiler chickens over their rearing period, correlating these changes with different probiotic treatments. Specific resistance mechanisms against critically important antibiotics were identified, including genes related to fluoroquinolone resistance and peptide antibiotic resistance. We also found genes with significant relevance to public health (aadK, AAC(6')-Ii) and multiple drug-resistance genes (vmlR, ykkC, ykkD, msrC, clbA, eatAv). Only one phage-encoded gene (dfrA43) was detected, with no evidence of plasmid or mobile genetic element transmission. Additionally, metagenomic analysis of fecal samples showed no significant changes corresponding to time or diet across groups. Our findings highlight the potential risks associated with the use of probiotics in poultry, particularly regarding the carriage of ARGs. It is crucial to conduct further research into the molecular genetics of probiotics to develop strategies that mitigate the risk of resistance gene transfer in agriculture, ensuring the safe and effective use of probiotics in animal husbandry.

Probiotic Yeast Saccharomyces: Back to Nature to Improve Human Health

Saccharomyces cerevisiae var. boulardii is best known for its treatment efficacy against different gastrointestinal diseases. This probiotic yeast can significantly protect the normal microbiota of the human gut and inhibit the pathogenicity of different diarrheal infections. Several clinical investigations have declared S. cerevisiae var. boulardii a biotherapeutic agent due to its antibacterial, antiviral, anti-carcinogenic, antioxidant, anti-inflammatory and immune-modulatory properties. Oral or intramuscular administration of S. cerevisiae var. boulardii can remarkably induce health-promoting effects in the host body. Different intrinsic and extrinsic factors are responsible for its efficacy against acute and chronic gut-associated diseases. This review will discuss the clinical and beneficial effects of S. cerevisiae var. boulardii in the treatment and prevention of different metabolic diseases and highlight some of its health-promising properties. This review article will provide fundamental insights for new avenues in the fields of biotherapeutics, antimicrobial resistance and one health.

Study of potential probiotic and biotechnological properties of non-Saccharomyces yeasts from fruit Brazilian ecosystems

Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes' amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.

Probiotic Properties of New Lactobacillus Strains Intended to Be Used as Feed Additives for Monogastric Animals

The study aimed to evaluate the safety and probiotic properties of selected Lactobacillus strains, which are intended to be fed to monogastric animals. The Lactobacillus spp. appeared to be safe since they did not degrade mucus and did not exhibit β-haemolysis. Moreover, the survival of Caco-2 cells in the presence of metabolites of the selected strains was high, which also indicated their safety. The analysed strains showed moderate or strong antagonistic activity against Salmonella spp., Listeria monocytogenes, Campylobacter jejuni and Campylobacter coli, which was tested with the usage of the agar slab method. Furthermore, the strains showed high survivability in an acidic environment and the presence of bile salts (~90%). High resistivity or moderate susceptibility to antibiotics was also observed, as a result of the disc diffusion method. The strains were mostly moderately hydrophilic (hydrophobicity: 10.43–41.14%); nevertheless, their auto-aggregation capability exceeded 50% and their co-aggregation with pathogens varied between 12.12 and 85.45%. The ability of the selected strains to adhere to Caco-2 cells was also analysed; they were found to be moderately adhesive (85.09–95.05%) and able to hinder pathogens attaching to the cells (up to 62.58%). The analysed strains exhibit probiotic properties, such as high survivability and adherence to epithelial cells; therefore, they are suitable for administration to monogastric animals. Since the overuse of antibiotic growth promoters in livestock leads to the spread of antibiotic-resistant pathogens and accumulation of chemotherapeutic residues in food of animal origin, it is of vital importance to introduce alternative feed additives.

In Vitro Detoxification of Aflatoxin B1, Deoxynivalenol, Fumonisins, T-2 Toxin and Zearalenone by Probiotic Bacteria from Genus Lactobacillus and Saccharomyces cerevisiae Yeast

The aim of the following research was to determine the detoxification properties of probiotic Lactobacillus sp. bacteria (12 strains) and S. cerevisiae yeast (6 strains) towards mycotoxins, such as aflatoxin B₁, deoxynivalenol, fumonisins, T-2 toxin and zearalenone, which pose as frequent feed contamination. The experiment involved analysing changes in concentration of mycotoxins in PBS solutions, after 6, 12 and 24 h of incubation with monocultures of tested microorganisms, measured by high-performance liquid chromatography (HPLC). We found that all strains detoxified the mycotoxins, with the highest reduction in concentration observed for the fumonisin B₁ and B₂ mixture, ranging between 62 and 77% for bacterial strains and 67–74% for yeast. By contrast, deoxynivalenol was the most resistant mycotoxin: its concentration was reduced by 19–39% by Lactobacillus sp. strains and 22–43% by yeast after 24 h of incubation. High detoxification rates for aflatoxin B₁, T-2 toxin and zearalenone were also observed, with concentration reduced on average by 60%, 61% and 57% by Lactobacillus, respectively, and 65%, 69% and 52% by yeast, respectively. The greatest extent of reduction in the concentration for all mycotoxins was observed after 6 h of incubation; however, a decrease in concentration was noted even after 24 h of incubation. Thus, the tested microorganisms can potentially be used as additives to decrease the concentrations of toxins in animal feed.

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.

In vitro and in vivo capacity of yeast-based products to bind to aflatoxins B1 and M1 in media and foodstuffs: A systematic review and meta-analysis

The aflatoxins are hepatotoxic and carcinogenic metabolites produced by Aspergillus species during growth on crop products. In this regard, a systematic review to collect the quantitative data regarding the in vitro capacity of yeasts-based products to bind to aflatoxin B₁ (AFB₁) and/or aflatoxin M₁ (AFM₁) was performed. After screening, 31 articles which met the inclusion criteria was included and then the pooled decontamination of aflatoxins in the defined subgroups (the type of foods, pH, contact time, temperature, yeast species, and aflatoxin type) was calculated by the random effect model (REM). The overall binding capacity (BC) of aflatoxins by yeast was 52.05% (95%CI: 49.01-55.10), while the lowest and highest aflatoxins' BC were associated with Yeast Extract Peptone (2.79%) and ruminal fluid + artificial saliva (96.21%), respectively. Regarding the contact time, temperature, pH and type of aflatoxins subgroups, the binding percentages varied from 50.83% (>300 min) to 52.66% (1-300 min), 50.71% (0-40 °C) to 88.39% (>40 °C), 43.03% (pH: 3.1-6) to 44.56% (pH: 1-3) and 59.35% (pH > 6), and 48.47% (AFB₁) to 69.03% AFM₁, respectively. The lowest and highest aflatoxins' BC was related to C. fabianii (18.45%) and Z. rouxii (86.40%), respectively. The results of this study showed that variables such as temperature, yeast, pH and aflatoxin type can be considered as the effective factors in aflatoxin decontamination.

Dephytinizing and Probiotic Potentials of Saccharomyces cerevisiae (NCIM 3662) Strain for Amelioration of Nutritional Quality of Functional Foods

Increase of undigested complexes of phytic acid in food is gaining serious attention to overcome nutritional challenges due to chelation effects. We investigated soil-borne yeast phytase from Saccharomyces cerevisiae (NCIM 3662) for dephytinization of foods, probiotic properties, and process development. The strain produced 45 IU/DCG by cell-bound phytase in an unoptimized medium was increased fourfold (164 IU/DCG) in 12 h using statistical media optimization. The process was scaled-up up to 10-L fermenter scale with increased phytase productivity of 6.4 IU/DCG/h as compared to the lab scale. The strain displayed probiotic characteristics like tolerance to artificial gastric acid conditions, hydrophobicity, autoaggregation, coaggregation, and bile salt hydrolase (BSH) activity. Further, it could dephytinize (removal of phytic acid; an anti-nutritional factor) functional foods like ragi (finger millet) flour, soya flour, chickpea flour, and poultry animal feed. A combination of cell-bound dephytinizing phytase and nutrition-ameliorating probiotic traits of S. cerevisiae (NCIM 3662) presents profound applications in food technology sector.