Reference | Amachawadi_2015_FooPatandDis (10239) (Excluded)

The study consisted of 240 weaned pigs (34 days old) with an average body weight (BW) of 7.0 kg (+/–1 kg). The piglets were housed in 2 barns, each consisting of 40 pens. For this study, only 24 pens (in each barn), which were divided into 4 quadrants of 6 pens each with 5 piglets per pen (n = 120 piglets per barn), were used. The pens were assigned randomly as an incomplete factorial design to 6 dietary treatment groups (4 pens/treatment in each barn): (1) a basal diet (16.5 mg/kg of feed of copper as copper sulfate, control group); (2) a basal diet supplemented with 125 mg/kg of feed of copper as copper sulfate (Cu group); (3) basal diet supplemented with chlortetracycline (CTC 50; Alpharma, Fort Lee, NJ) at 22 mg/kg BW; (4) basal diet supplemented with tylosin (Tylan 100; Elanco Animal Health, Greenfield, IN) at 22 mg/kg BW; (5) basal diet with both 125 mg/kg of feed of copper and chlortetracycline at 22 mg/kg BW (CuCTC group); and (6) basal diet with both 125 mg/kg of feed of copper and tylosin at 22 mg/kg BW (CuTyl group). Initially, all piglets received basal diet as per National Research Council recommendations (NRC, 1998). The basal diet consisted of corn, soybean meal, vitamins, amino acids, and trace mineral supplements. Following a week of acclimatization (pretreatment) to the basal diet, piglets were fed treatment diets for 3 weeks followed by a washout (posttreatment) phase of 2 weeks during which piglets were fed the basal diet with no supplemental copper or antibiotics.

Rectal fecal samples were collected randomly from 3 piglets per pen on days 0, 7, 14, 21, 28, and 35 and were placed in individual Whirl-Pak (Nasco, Ft. Atkinson, WI) bags.

AST Method: Multiple Methods

Reference explicitly reports AST breakpoints: Uncertain

Reference reports using a MIC table: True