The Effect of Live Yeast and Yeast Extracts Included in Lactation Diets on Antimicrobial Susceptibility of Fecal Escherichia coli in Sows

A total of 27 sows (Line 241; DNA Genetics) were used in a study to evaluate the effect feeding live yeast and extracts lactating on antimicrobial susceptibilities fecal E. coli. Sows blocked by BW parity d 110 gestation allotted 1 2 dietary treatments. Dietary treatments consisted standard corn-soybean meal lactation diet or that contained yeast-based pre- probiotics (0.10% Actisaf Sc 47 HR+ 0.025% SafMannan; Phileo Lesaffre, Milwaukee, WI). Diets fed from until weaning (approximately 19). Sow samples collected determine susceptibility coli upon entry into farrowing house at for each treatment. The was isolated samples, species confirmation accomplished PCR detection uidA clpB genes. Microbroth dilution method minimal inhibitory concentrations (MIC) isolates 14 different antimicrobials. Isolates categorized as either susceptible, intermediate, resistant based Clinical Laboratory Standards Institute guidelines (CLSI, 2018). An interaction (P = 0.026) × sampling day observed cefoxitin where showed no significant differences 0.237) MIC values entry, but control had lower 0.035) compared additives. There main effects > 0.10) resistance (AMR) an increased < 0.02) trend towards 11 antimicrobials over time. Fecal tetracycline ceftriaxone weaning. All other considered susceptible intermediate across day. In conclusion, did not influence sow litter performance measurements AMR during except cefoxitin, which higher end when present diet.