The effect and mode of action of saponins on the microbial populations and fermentation in the rumen and ruminant production

The growing public concerns over chemical residues in animal-derived foods and threats of antibiotic-resistant bacteria have renewed interest in exploring safer alternatives to chemical feed additives in ruminant livestock. Various bioactive phytochemicals including saponins appear to be potential ‘natural’ alternatives to ‘chemical’ additives in modulating rumen fermentation favourably and animal performance. Saponins are a diverse group of glycosides present in many families of plants. The primary effect of saponins in the rumen appears to be to inhibit the protozoa (defaunation), which might increase the efficiency of microbial protein synthesis and protein flow to the duodenum. Furthermore, saponins may decrease methane production via defaunation and/or directly by decreasing the activities (i.e. rate of methanogenesis or expression of methane-producing genes) and numbers of methanogens. Saponins may also selectively affect specific rumen bacteria and fungi, which may alter the rumen metabolism beneficially or adversely. The ammonia-adsorption and modulation of digesta passage in the rumen by saponins have also been implicated in altering rumen metabolism, but their physiological responses are likely to be negligible compared with microbiological effects. The effects of saponins on rumen fermentation have not been found to be consistent. These discrepancies appear to be related to the chemical structure and dosage of saponins, diet composition, microbial community and adaptation of microbiota to saponins. There is need for systematic research based on chemical structures of saponins, nutrient composition of diets and their effects on rumen microbial ecosystem to obtain consistent results. The present paper reviews and discusses the effects and mode of action of saponins on microbial community and fermentation in the rumen, and ruminant performance.

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Assessing the Molecular Targets and Mode of Action of Furanone C-30 on Pseudomonas aeruginosa Quorum Sensing

Molecules ◽

10.3390/molecules26061620 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1620

Author(s):

Victor Markus ◽

Karina Golberg ◽

Kerem Teralı ◽

Nazmi Ozer ◽

Esti Kramarsky-Winter ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Quorum Sensing ◽

Conformational Changes ◽

Mode Of Action ◽

Pathogenic Bacteria ◽

Molecular Targets ◽

Resistant Bacteria ◽

Public Healthcare ◽

C 30

Quorum sensing (QS), a sophisticated system of bacterial communication that depends on population density, is employed by many pathogenic bacteria to regulate virulence. In view of the current reality of antibiotic resistance, it is expected that interfering with QS can address bacterial pathogenicity without stimulating the incidence of resistance. Thus, harnessing QS inhibitors has been considered a promising approach to overriding bacterial infections and combating antibiotic resistance that has become a major threat to public healthcare around the globe. Pseudomonas aeruginosa is one of the most frequent multidrug-resistant bacteria that utilize QS to control virulence. Many natural compounds, including furanones, have demonstrated strong inhibitory effects on several pathogens via blocking or attenuating QS. While the natural furanones show no activity against P. aeruginosa, furanone C-30, a brominated derivative of natural furanone compounds, has been reported to be a potent inhibitor of the QS system of the notorious opportunistic pathogen. In the present study, we assess the molecular targets and mode of action of furanone C-30 on P. aeruginosa QS system. Our results suggest that furanone C-30 binds to LasR at the ligand-binding site but fails to establish interactions with the residues crucial for the protein’s productive conformational changes and folding, thus rendering the protein dysfunctional. We also show that furanone C-30 inhibits RhlR, independent of LasR, suggesting a complex mechanism for the agent beyond what is known to date.

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Antimicrobial Susceptibility of Lactic Acid Bacteria Strains of Potential Use as Feed Additives - The Basic Safety and Usefulness Criterion

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.687071 ◽

2021 ◽

Vol 8 ◽

Author(s):

Ilona Stefańska ◽

Ewelina Kwiecień ◽

Katarzyna Jóźwiak-Piasecka ◽

Monika Garbowska ◽

Marian Binek ◽

...

Keyword(s):

Antibiotic Resistance ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Resistance Genes ◽

Pathogenic Bacteria ◽

Feed Additives ◽

Health Concern ◽

Resistant Bacteria ◽

Safety Criterion ◽

Phenotypic Resistance

The spread of resistance to antibiotics is a major health concern worldwide due to the increasing rate of isolation of multidrug resistant pathogens hampering the treatment of infections. The food chain has been recognized as one of the key routes of antibiotic resistant bacteria transmission between animals and humans. Considering that lactic acid bacteria (LAB) could act as a reservoir of transferable antibiotic resistance genes, LAB strains intended to be used as feed additives should be monitored for their safety. Sixty-five LAB strains which might be potentially used as probiotic feed additives or silage inoculants, were assessed for susceptibility to eight clinically relevant antimicrobials by a minimum inhibitory concentration determination. Among antimicrobial resistant strains, a prevalence of selected genes associated with the acquired resistance was investigated. Nineteen LAB strains displayed phenotypic resistance to one antibiotic, and 15 strains were resistant to more than one of the tested antibiotics. The resistance to aminoglycosides and tetracyclines were the most prevalent and were found in 37 and 26% of the studied strains, respectively. Phenotypic resistance to other antimicrobials was found in single strains. Determinants related to resistance phenotypes were detected in 15 strains as follows, the aph(3″)-IIIa gene in 9 strains, the lnu(A) gene in three strains, the str(A)-str(B), erm(B), msr(C), and tet(M) genes in two strains and the tet(K) gene in one strain. The nucleotide sequences of the detected genes revealed homology to the sequences of the transmissible resistance genes found in lactic acid bacteria as well as pathogenic bacteria. Our study highlights that LAB may be a reservoir of antimicrobial resistance determinants, thus, the first and key step in considering the usefulness of LAB strains as feed additives should be an assessment of their antibiotic resistance. This safety criterion should always precede more complex studies, such as an assessment of adaptability of a strain or its beneficial effect on a host. These results would help in the selection of the best LAB strains for use as feed additives. Importantly, presented data can be useful for revising the current microbiological cut-off values within the genus Lactobacillus and Pediococcus.

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Effect of earthworms in removal and fate of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) during clinical laboratory wastewater treatment by vermifiltration

10.1101/2020.10.01.321885 ◽

2020 ◽

Author(s):

Sudipti Arora ◽

Sakshi Saraswat ◽

Ankur Rajpal ◽

Harshita Shringi ◽

Rinki Mishra ◽

...

Keyword(s):

Wastewater Treatment ◽

Microbial Community ◽

Clinical Laboratory ◽

Community Diversity ◽

Resistance Pattern ◽

Resistant Bacteria ◽

Significant Shift ◽

Antibiotic Resistant Bacteria ◽

Antibiotic Resistant ◽

Natural Treatment

AbstractThe wastewater treatment plants effluent has been implicated in the spread of antibiotic resistant bacteria (ARB) as these environment contains multiple selective pressures that may increase mutation rates, pathogen survivability, and induce gene transfer between bacteria. In lieu of this, the present study explored the dynamics of earthworm-microorganisms interactions on the treatment efficacy of clinical laboratory wastewater treatment by vermifiltration and the effect of earthworms in the fate of removal of pathogens and ARB. The results of the study showed that earthworms and VF associated microbial community had a significant effect on BOD and COD reduction (78-85%), pathogen removal (>99.9 %) and caused a significant shift in the prevalence pattern of ARB. Additionally, molecular profiling of ESBL (blaSHV, blaTEM and blaCTX-M), MRSA (mec-A) and Colistin (mcr-1) gene confirmed the probable mechanisms behind the resistance pattern. The microbial community diversity assists in the formation of biofilm, which helps in the removal of pathogens and results in a paradigm shift in the resistance profile of ARB and ARG, specifically most effective against drugs, targeting cell wall and protein synthesis inhibition like Ampicillin, Ticarcillin, Gentamicin and Chloramphenicol. These findings prove vermifiltration technology as a sustainable and natural treatment technology for clinical laboratory wastewater.

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The effect of probiotics, phytobiotics and their combination as feed additives in the diet of dairy calves on performance, rumen fermentation and blood metabolites during the preweaning period

Animal Feed Science and Technology ◽

10.1016/j.anifeedsci.2020.114738 ◽

2020 ◽

pp. 114738

Author(s):

Barbara Stefańska ◽

Jacek Sroka ◽

Frank Katzer ◽

Piotr Goliński ◽

Włodzimierz Nowak

Keyword(s):

Rumen Fermentation ◽

Feed Additives ◽

Dairy Calves ◽

Blood Metabolites ◽

Preweaning Period

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Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments

Applied and Environmental Microbiology ◽

10.1128/aem.00234-11 ◽

2011 ◽

Vol 77 (14) ◽

pp. 4974-4980 ◽

Cited By ~ 17

Author(s):

Emerancienne Mogoa ◽

Charles Bodet ◽

Franck Morel ◽

Marie-Hélène Rodier ◽

Bernard Legube ◽

...

Keyword(s):

Electron Microscopy ◽

Flow Cytometry ◽

Chlorine Dioxide ◽

Mode Of Action ◽

Cellular Response ◽

Acanthamoeba Castellanii ◽

Size Reduction ◽

Resistant Bacteria ◽

Free Living ◽

Content Type

ABSTRACTAcanthamoeba castellaniiis a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested onA. castellaniitrophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action onA. castellanii.

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Review of mycotoxin‐detoxifying agents used as feed additives: mode of action, efficacy and feed/food safety

EFSA Supporting Publications ◽

10.2903/sp.efsa.2009.en-22 ◽

2009 ◽

Vol 6 (9) ◽

Cited By ~ 42

Author(s):

Caroline BOUDERGUE ◽

Christine BUREL ◽

Sylviane DRAGACCI ◽

Marie‐Christine FAVROT ◽

Jean‐Marc FREMY ◽

...

Keyword(s):

Food Safety ◽

Mode Of Action ◽

Feed Additives

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Distinct Effects of Bovicin HC5 and Virginiamycin on in vitro Ruminal Fermentation and Microbial Community Composition

Journal of Agricultural Science ◽

10.5539/jas.v10n8p156 ◽

2018 ◽

Vol 10 (8) ◽

pp. 156

Author(s):

Sofia Magalhaes Moreira ◽

Claudia Braga Pereira Bento ◽

Analice Claudia Azevedo ◽

Hilario C. Mantovani

Keyword(s):

Microbial Community ◽

Community Composition ◽

Microbial Community Composition ◽

Gas Production ◽

Feed Additives ◽

Molecular Fingerprinting ◽

Ruminal Fermentation ◽

Multiresistant Bacteria ◽

Bovicin Hc5

Antibiotics are used as feed additives for cattle to alter rumen fermentation and increase weight gain. However, this practice can potentially lead to the presence of antibiotic residues in milk and meat and the selection of multiresistant bacteria. Bacteriocins have been suggested as an alternative to antibiotics used in animal production. This work aimed to evaluate the in vitro effects of bovicin HC5 and virginiamycin on ruminal fermentation and on microbial community composition. Ruminal fluid was collected from fistulated cows fed corn silage and incubated with Trypticase (15 g L-1). Cultures treated with bovicin HC5 or virginiamycin decreased (P < 0.05) ammonia accumulation by 47.46% and 66.17%, respectively. Bovicin HC5 and virginiamycin also decreased (P < 0.05) the concentration of organic acids and gas production, but the effects were somewhat distinct. Molecular fingerprinting of the microbial community using PCR-DGGE revealed that community structure varied between treatments and were distinct from the controls. These results demonstrate that bovicin HC5 and virginiamycin have distinct effects on ruminal fermentation and modify differently the microbial community composition. These results also expand the knowledge about the effects of antibiotics and bacteriocins on bacterial and archaeal communities involved in protein metabolism in the rumen.

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