Measurements and sample collection
Pigs were allowed to become familiar with their surroundings and diets after weaning. Therefore, all measurements started to be recorded on day 3 after weaning and it was considered experimental day 0. Pigs were weighed individually on experimental days 0, 7, and 14. Growth rate was calculated as the average of daily gain per pen, and expressed as per pig (ADG). Feed offered and orts were recorded daily and expressed as average feed intake per pig (ADFI). Feed efficiency was calculated as grams of body weight gain per kilogram of feed intake and it was expressed as the body weight gain to feed intake ratio (G:F). Feces consistency was scored per pen every morning, using a visual scale as follows: 1, severe diarrhea; 2, mild diarrhea; 3, soft feces; 4, normal feces; 5, firm but dry feces.
A blood sample was collected from 1 barrow and 1 gilt selected randomly per pen on experimental day 14. Blood (3 mL) was collected in tubes (BD Vacutainer® Blood Collection Tube, BD Co., USA) containing EDTA and mixed immediately to avoid coagulation. Plasma was obtained after centrifugation at 3000 × g for 15 min at 4 °C, and then stored at −80 °C until analysis. Plasma samples were pooled within treatments for immune reactivity analyses.