TY - JOUR 
A1 - Montoro-Dasí, Laura
AU - Villagra, Arantxa
AU - Sevilla-Navarro, Sandra
AU - Pérez-Gracia, María T.
AU - Vega, Santiago
AU - Marín, Clara
T1 - Commensal Escherichia coli Antimicrobial Resistance and Multidrug-Resistance Dynamics during Broiler Growing Period: Commercial vs. Improved Farm Conditions
Y1 - 2021
SN - 2076-2615
UR - http://hdl.handle.net/20.500.11939/7522
AB - New measures applied to reduce antimicrobial resistances (AMR) at field level in broiler
production are focused on improving animals’ welfare and resilience. However, it is necessary to
have better knowledge of AMR epidemiology. Thus, the aim of this study was to evaluate AMR and
multidrug resistance (MDR) dynamics during the rearing of broilers under commercial (33 kg/m2
density and max. 20 ppm ammonia) and improved (17 kg/m2 density and max. 10 ppm ammonia)
farm conditions. Day-old chicks were housed in two poultry houses (commercial vs. improved),
and no antimicrobial agents were administered at any point. Animals were sampled at arrival day,
mid-period and at slaughter day. High AMR rates were observed throughout rearing. No statistical
differences were observed between groups. Moreover, both groups presented high MDR at slaughter
day. These results could be explained by vertical or horizontal resistance acquisition. In conclusion,
AMR and MDR are present throughout rearing. Moreover, although a lower level of MDR was
observed at mid-period in animals reared under less intensive conditions, no differences were found
at the end. In order to reduce the presence of AMR bacteria in poultry, further studies are needed to
better understand AMR acquisition and prevalence in differing broiler growing conditions.
KW - Multidrug resistance
KW - L73  Animal diseases
KW - L01  Animal husbandry
KW - L70  Veterinary science and hygiene
KW - L50  Animal physiology and biochemistry
KW - Antimicrobial resistance
KW - Broilers
KW - Farm management
KW - Escherichia coli
LA - en
PB - MDPI
ER -