2.3. Animals and experimental design
A total of 18 crossbred (Duroc × Landrace × Yorkshire) weaning piglets (weaned on d 23, initial body weight 7.42 ± 0.19 kg) were randomly assigned to 3 experimental groups (6 pigs per treatment, half males and half females): control group, K88 challenged group and CGMP treated group. Control group and K88 challenged group were fed a corn–soybean basal diet, and CGMP treated group was fed the basal diets supplemented with 1% CGMP. All piglets had ad libitum access to feed and water throughout the 12-day trial. All weaning pigs were fed the basal diet for 3 days as pretreatment. In days 8–10, 30 mL of 10% (w/v) NaCHO3 and 20% (w/v) sucrose solution was orally administered to all of the piglets, and 30 min later, 30 mL of LB broth containing 109 CFU/mL of E. coli K88 was inoculated to the K88 challenged group and CGMP treated group, while 30 mL of sterile LB broth was inoculated to the control group. The average daily gain (ADG), average daily feed intake (ADFI), and feed/gain (F/G) of each pig were monitored throughout the experimental period. The fecal scores were graded by Castillo et al. (2008) (0 = normally shaped feces, 1 = shapeless feces, 2 = soft feces, and 3 = thin, liquid feces).