Spray-dried plasma improves growth performance and reduces inflammatory status of weaned pigs challenged with enterotoxigenic Escherichia coli K88

ABSTRACT: We investigated whether spray-dried plasma (SDP) improved growth and health of piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC). Forty-eight pigs weaned at 21 d (BW = 4.88 ± 0.43 kg) received one of four diets containing 6% SDP or fish proteins either non medicated (SDP-NM and FP-NM diets), or medicated with 0 or 250 mg/kg colistine + 500 mg/kg amoxycycline (SDP-M and FP-M diets), for 15 d. On d 4, pigs where orally challenged with ETEC. On d 15, eight pigs per dietary group were killed, blood and saliva were collected for analysis of K88 fimbriae specific immunoglobulin (Ig)-A, and jejunum was removed for villi preparation, histological analysis and cytokine expression. The presence or absence of K88 receptors (K88+ and K88- pigs respectively) was determined by villous adhesion assay. Effects of protein source on ADG (P = 0.04) and ADFI (P < 0.01) as well of medication on ADFI (P < 0.02) of all pigs were observed. In sacrified pigs, there was an effect of protein source on ADG (P = 0.03) and ADFI (P < 0.001), as well an interaction between medication and presence of K88 receptor (P = 0.02) for feed: gain ratio. Plasma K88 specific IgA were low in all K88- pigs and higher in K88+ pigs fed FP-NM as compared to all the other groups (P < 0.05), except SDP-M. An interaction was found among protein source, medication and presence of K88 receptors (P = 0.04 ). Saliva IgA were high in all pigs fed FP-NM and low in all the other pigs. Jejunum of pigs fed FP-NM showed some ulcerations, edema, and mild inflammatory cell infiltration (ICI). In pigs fed FP-M edema was reduced. Conversely, only a mild ICI was observed in pigs fed SDP-NM and SDP-M. Crypt depth was increased in K88+ pigs fed SDP-NM and an interaction between protein source and presence of K88 receptors was observed (P <0.05). Expressions of tumor necrosis factor (TNF)-a and interleukin (IL)-8 were lower in pigs fed SDP-NM and SDP-M than in those fed FP-NM and FP-M, either K88- or K88+(P < 0.01). In pigs fed FP diets, expression of IL-8 tended to increase (P = 0.08) in K88+, as compared to K88- subjects. Expression of interferon (IFN)-g increased in K88- and K88+ pigs fed FP-M as compared to all the other pigs (P < 0.01). These results indicate that feeding with SDP improves growth performance and protects against E. coli induced inflammatory status, and suggest that use of SDP-NM can be considered a valid antibiotic alternative