Figure 1.

Growth promotion by in-feed antimicrobials (AMA) is paralleled by inconsistent alterations in the metabolic profile of pigs. Two independent cohorts of piglets were weaned and fed for 35 days cereal-based diets medicated with combinations of AMA, which were either zinc oxide, amoxicillin, and colistin (ZAC) or zinc oxide, chlortetracycline, and tiamulin (ZCT) at dosing levels routinely used for preventing bacterial enteritis and stimulating pig growth. Control pigs (CON) received no AMA. Plasma collected on days 34 and 35 were used to measure biomarkers by ELISA. Data from the two experiments were combined in the figure. (A,B) Weight gain, (C,D) average daily feed intake, and circulating concentration of metabolites (E–J) and hormones (K–P) in pigs fed CON or medicated (ZAC and ZCT) diets. Data were analyzed with ANOVA. Least squares means ± SEM are plotted, ^*P < 0.05, ^**P < 0.01, n = 6–12.