Response of early-weaned pigs to an enterotoxigenic Escherichia coli (K88) challenge when fed diets containing spray-dried porcine plasma or pea protein isolate plus egg yolk antibody, zinc oxide, fumaric acid, or antibiotic

Abstract

The effect of feeding diets containing either spray-dried porcine plasma (SDPP) or pea protein-isolate (PPI) supplemented with either egg yolk antibodies (EYA) from hens immunized with enterotoxigenic Escherichia coli (ETEC) (K88 and F18) antigens, ZnO, fumaric acid (FA), or carbadox (AB) on pig performance, incidence of scours, and gut morphology was studied in a 14-d experiment. Ninety 10-d-old weaned pigs were assigned to six dietary treatments in a completely randomized design to give five pens per treatment with three pigs per pen. The diets were SDPP without EYA (SDPP − EYA), PPI without EYA (PPI − EYA), PPI with EYA (PPI + EYA), PPI with ZnO (PPI + ZnO), PPI with FA (PPI + FA), or PPI with AB (PPI + AB). Diets were formulated to similar nutrient levels, with AB, EYA, FA, and ZnO at 0.25, 0.5, 2.0, and 0.4% of the diet, respectively. Pigs were weighed and bled on d 0, 7, and 14 to determine plasma urea N (PUN). Pigs were orally challenged with a 6-mL dose of 10¹⁰ cfu/mL ETEC (K88) on d 7. On d 14, three pigs per treatment were killed to obtain sections of the small intestine for histological measurements. Weekly feed intake, BW changes, and gain:feed were determined. Incidence of scours and scour scores were monitored and fecal swabs were taken before and after ETEC challenge for PCR test to detect ETEC (K88). Feeding SDPP or supplementing PPI-based diets with EYA, ZnO, FA, or AB did not affect (P > 0.05) ADG, ADFI (as-fed basis), or gain:feed throughout the study. However, pigs fed PPI-EYA tended to have lower (P = 0.08) ADFI during wk 2 (137.9 g/d) and lower (P < 0.10) ADG from d 0 to 14 (100.1 g/d) than those fed the SDPP − EYA (156.6 g/d), PPI + EYA (151.2 g/d), PPI + ZnO (158.9 g/d), PPI + FA (155.4 g/d), and PPI + AB (152.6 g/d) diets. Although scours was evident in all pigs 8 h after the ETEC challenge, it lasted only 3 to 5 d in pigs fed SDPP or PPI supplemented with EYA, ZnO, FA, or AB. Pigs fed PPI-EYA continued to have severe diarrhea, resulting in 40% mortality vs. 13% or less in the other groups. The PCR results showed that 81% of PPI-fed pigs continued to shed ETEC K88 7 d after ETEC challenge. Pigs fed PPI-EYA had shorter villi (P < 0.05), reduced villi:crypt ratio (P < 0.003), and higher intestinal pH (P < 0.001) and PUN (P < 0.001) than those fed SDPP or PPI supplemented with EYA, ZnO, FA, and AB. In conclusion, SDPP, EYA, ZnO, FA, and AB may have provided passive control to ETEC (K88) infection and potentially enabled young pigs to efficiently utilize a PPI-based diet.