V3 Effect of feed supplementation with humic substances on phenotypic resistance profiles of Escherichia coli isolates from the ceca of broiler chickens / Pipová Monika, Jevinová Pavlína, Semjon Boris, Regecová Ivana, Marcinčák Slavomír, Nagy Jozef. In: Poultry Science. -ISSN 0032-5791, -Vol. 104, no. 7 (2025), art. no. 105175, p. 1-11

Basic data
OCA1. Surname awarded to the assessed person	Pipová
OCA2. Name awarded to the assessed person	Monika
OCA3. Degrees awarded to the assessed person	Assoc. prof. , DVM, CSc.
OCA4. Hyperlink to the entry of the person in the Register of university staff	https://www.portalvs.sk/regzam/detail/6030
OCA5. Area of assessment	study programme food hygiene · III. degree
OCA6. Category of the research/artistic/other output	scientific output
OCA7. Year of publication of the research/artistic/other output	2025
OCA8. ID of the record in the Central Registry of Publication Activity (CRPA) or the Central Registry of Artistic Activity (CRAA)	ID: 1356811
OCA9. Hyperlink to the record in CRPA or CRAA	https://app.crepc.sk/?fn=detailBiblioFormChildK3J2&sid=501BC45481E06D38281D79038C20&seo=CREP%C4%8C-detail-%C4%8Cl%C3%A1nok
Characteristics of the output that is not registered in CRPA or CRAA
OCA10. Hyperlink to the record in another publicly accessible register, catalogue of research/ artistic/other outputs	https://www.sciencedirect.com/science/article/pii/S0032579125004171
OCA11. Characteristics of the output in the format of the CRPA or the CRAA bibliographic record, if the output is not available in a publicly accessible register or catalogue of outputs	V3 Effect of feed supplementation with humic substances on phenotypic resistance profiles of Escherichia coli isolates from the ceca of broiler chickens / Pipová Monika, Jevinová Pavlína, Semjon Boris, Regecová Ivana, Marcinčák Slavomír, Nagy Jozef. In: Poultry Science. -ISSN 0032-5791, -Vol. 104, no. 7 (2025), art. no. 105175, p. 1-11
OCA12. Type of the output (if the output is not registered in CRPA or CRAA)
OCA13. Hyperlink to the webpage where the output is available (full text, other documentation, etc.)	https://www.researchgate.net/publication/390865592_Effect_of_feed_supplementation_with_humic_substances_on_phenotypic_resistance_profiles_of_Escherichia_coli_isolates_from_the_ceca_of_broiler_chickens
OCA14. Characteristics of the author's contribution	The author participated in the isolation and identification of bacterial isolates from the cecal contents of broiler chickens, tested the phenotypic resistance of identified bacterial strains to selected antimicrobial agents, prepared and revised the manuscript, and subsequently made the final edits prior to publication.
OCA15. Annotation of the output with contextual information concerning the description of creative process and the content of the research/artistic/other activity, etc.	The cecal contents of 80 broiler chickens divided into two groups (control and experimenta , 40 broilers each) and slaughtered in 37 days of age . were submitted to microbiological analysis focused on the isolation and identification of Escherichia coli, Chickens of both groups were fed standard commercial feeds, but the diet for experimental chicken was permanently supplemented with humic substances (HS) in the amount of 0.7% . Following the genotypic identification of E. coli isoaltes by the species-specific PCR method, 58 E. coli strains from control chickens and 60 strains from experimental chikens were tested for resistance against 19 antimicrobials using the broth microdilution method. Based on minimum inhibitory concentrations, resistance to at least one antimicrobial was detected in almost 90 % of E. coli isolates from control chickens, but in only 68.33% of isolates from experimental broilers. In the experimental group, a noticeable decrease in resistance rates for ampicillin (31.78%), trimethoprim (22.88%), sulfamethoxazol (20.86%), and tetracycline (19.71%) was observed. Feed supplementation with humic substances also reduced the prevalence of multidrug resistance (20.0% vs. 43.1%) and led to a complete elimination of E. coli strains resistant to six and more antimicrobial classes. Based on phenotypic resistance profiles, no extended-spectrum beta-lactamase production could be confirmed among E. coli isolates from HS-fed broilers. This study proved a direct beneficial effect of HS-supplemented diet on the phenotypic resistance profiles of E. coli isolates from the ceca of commercially raised broiler chickens,
Other data
OCA16. Annotation of the output in English	Humic substances (HS), natural complex-forming feed additives, are believed to reduce the bioavailability of antimicrobials to the gut microbiome, thereby limiting the emergence and spread of antimicrobial resistance in the food chain. However, this hypothesis has not yet been adequately verified experimentally. Our study was focused on the isolation of Escherichia coli (E. coli) from the ceca of 80 broiler chickens bred for 37 d under controlled conditions. Chickens in the control and experimental groups (40 broilers each) were fed standard commercial feeds, but the diet for experimental chicken was permanently supplemented with HS (99.3% feed + 0.7% HS). After slaughter and evisceration at the end of fattening period, the cecal contents of all chickens were subjected to microbiological analysis aimed at the enumeration, isolation and genotypic identification of E. coli strains by the species-specific PCR method. In total, 58 E. coli strains from control chickens and 60 strains from HS-fed chickens were tested for resistance against 19 antimicrobials using the broth microdilution method based on minimum inhibitory concentration breakpoints. Resistance to at least one antimicrobial was detected in almost 90% of E. coli isolates from control chickens, but in only 68.33% of isolates from HS-fed broilers (P < 0.01). In the experimental group, a noticeable decrease in resistance rates for ampicillin (31.78%), trimethoprim (22.88%), sulfamethoxazol (20.86%), and tetracycline (19.71%) was observed. The effect for fluorochinolones was less pronounced (0.09 ≤ P < 0.90). Feed supplementation with HS also reduced the prevalence of multidrug resistance (20.0% vs. 43.1%; P < 0.01) and led to a complete elimination of co-resistance to six and more antimicrobial classes. Additionally, no extended-spectrum beta-lactamase production could be predicted for E. coli isolates from HS-fed broilers. This is probably the first experimental study demonstrating a direct beneficial effect of HS-supplemented diet on the phenotypic resistance profiles of E. coli isolates from the ceca of commercially raised broiler chickens, showing that HS as feed additives can effectively reduce the phenotypic expression of antimicrobial resistance in E. coli.
OCA17. List of maximum 5 most significant citations corresponding to the output
OCA18. Characteristics of the output's impact on socio-economic practice	The results of this experimental study proved that the supplementation of feed for broiler chickens with humic substances can significantly reduce the phenotypic manifestations of resistance to commonly used human and veterinary drugs in Escherichia coli bacteria as part of the intestinal microbiome, thereby reducing the risk of antimicrobial resistance being transmitted to humans through the food chain.
OCA19. Characteristics of the output and related activities' impact on the educational process	In the compulsory subject \"Food Microbiology and Foodborne Diseases\" and the compulsory elective subject \"Food Microbiology\" at the third level of higher education, special attention is paid to methods used to test the sensitivity of bacterial isolates from food and farm animals to antimicrobial agents commonly used in human and veterinary medicine.