Effects of dietary protein supply, weaning age and experimental enterotoxigenic Escherichia coli infection on newly weaned pigs: health

Abstract

Weaning is often associated with post-weaning colibacillosis (PWC), caused by enterotoxigenic Escherichia coli (ETEC). The objective was to investigate the effects of manipulating dietary protein supply and increasing weaning age on enteric health and ETEC shedding of newly weaned pigs exposed to an experimental ETEC challenge. The experiment consisted of a complete 2 3 2 3 2 factorial combination of weaning age (4 v. 6 weeks), dietary protein content (H, 230 g crude protein (CP)/kg v. L, 130 g CP/kg) and experimental ETEC challenge (1 v. 2); all foods were free from in-feed antimicrobial growth promoters (AGP). An additional four treatments were added to allow the effect of protein source (DSMP, dried skimmed milk powder v. SOYA, soybean meal) and AGP inclusion (yes v. no) to be investigated in challenged pigs of both weaning ages. On day 3 post-weaning challenged pigs were administered per os with 10 9 cfu ETEC O149. A subset of pigs was euthanased on days 0 and 6 post weaning to assess enteric health and small intestine morphology. Both weaning age and dietary protein content affected the consequences of ETEC challenge. ETEC excretion persisted longer in the 4-week-weaned pigs than those weaned at 6 weeks. Although not significant, the numbers of ETEC shed in the faeces post infection (days 4 to 14) were higher on the H than L diet, especially in the 4-week-weaned pigs (P 5 0.093). Lowering CP level led to significantly firmer faeces post challenge (days 3 to 6) and decreased colonic digesta pH. Protein level had no effect on small intestine villous heights or crypt depths. There was no significant effect of protein source on ETEC excretion or enteric health. Results suggest that increasing weaning age and decreasing the level of dietary protein, especially in earlier weaned pigs, may help to maintain enteric health and minimise the effects of PWC.

Increasing weaning age of piglets from 4 to 7 weeks reduces stress, increases post-weaning feed intake but does not improve intestinal functionality

“…This study shows that when piglets are weaned at 7 weeks an increased sensitivity for ETEC-induced diarrhoea also exists. This has been shown before for piglets weaned at 6 or 7 weeks and challenged with ETEC, with a longer-lasting ETEC excretion in 4-week-weaned piglets than in 6-week-weaned piglets (Wellock et al, 2008;Sørensen et al, 2009). That creep feeding did not diminish the reduction in net fluid absorption by ETEC in our study but creep feed intake achieved by intermittent suckling did (Nabuurs et al, 1996;Kuller et al, 2007), implies that either the amount of creep feed consumed and/or the way of weaning is important for diminished fluid absorption by ETEC after weaning.…”

Effects of dietary protein supply, weaning age and experimental enterotoxigenic Escherichia coli infection on newly weaned pigs: performance

“…Treatments were assigned to pens with each of the treatments being represented in each of the experimental rooms. Six pigs from each weaning age on day 0 and four pigs per treatment on day 6 were euthanased to assess enteric health (see Wellock et al, 2008). Performance of the remaining animals was monitored until 10 weeks of age (day 28 for 6-week weaned and day 42 for 4-week weaned animals).…”

“…An analysis of the data regarding the effect of experimental treatment on ETEC shedding and enteric health is reported separately (Wellock et al, 2008).…”

Down-regulation of monocarboxylate transporter 1 (MCT1) gene expression in the colon of piglets is linked to bacterial protein fermentation and pro-inflammatory cytokine-mediated signalling

“…For example, protein level and quality in pig diets have been shown to be related to diarrhoea and shedding of enterotoxigenic Escherichia coli after a challenge (5,6) . A promising approach to reduce the formation of harmful metabolites from protein fermentation in the large intestine is the inclusion of fermentable carbohydrates in the diet (4,7,8) .…”