Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Modulation of the gut health and integrity in weaned piglets by feeding flaxseed and oats as polyfunctional ingredients

Flaxseed (Linum usitatissimum) and oats (Avena sativa) gain a renewed scientific interest in the context of searching for antibiotic alternatives in diets for piglets after weaning. Both plants possess mucilage-rich compounds, which may serve as a “bio-film” lining along the surface (mucus layer) of epithelial cells, and thus protecting against pathogenic colonisation, particularly after weaning. The physiological benefits of flaxseed oil are also attributed to the high content of á-linolenic acid, which is essential for mucosal growth and immunity.

Flaxseed protein may also stimulate insulin secretion, whereas lignans and other phenolics are known to have strong anti-oxidative and protein-binding properties that may suggest some preventive effect of flaxseed protein in conjunction with phenolics against bacterial overgrowth. Beta glucan from oats is a soluble, viscous fibre found in the bran layer of the grain, which can stimulate the function or secretion of various immunoglobulins and immune system cells, and up-regulated immune mechanisms can enhance resistance to some pathogens.

Therefore, the aim of this study was to test the potency of flaxseed and oats in a cereal-based, antibiotic-free diet on the gut health, mucosal integrity and performance of weaned piglets before and after exposure to a controlled infection with enterotoxigenic E. coli K88.

In total 48 piglets of approximately 8 kg BW were used during 19 days post-weaning to test if adding 10% flaxseed and 15% oats (as polyfunctional/anti-diarrhoetic ingredients rich in mucilage for protecting the surface of epithelial cells) in diets without antibiotics can positively affect the performance, health and integrity of the digestive tract in weaned piglets exposed to a controlled pathogenic infection with ETEC K88 on day 6-postweaning.

They were allotted to 4 dietary treatments: 1) Basal, no E.coli infection (B); 2) Basal+E.coli infection (B+); 3) Basal+10% flaxseed +E.coli infection (BF+); 4) Basal + 15% oats + E.coli infection (BO+). Their responses to the dietary treatments were evaluated in terms of clinical health status, performance, faecal consistency index (scale 0-3), activity index (scale 0-4), breath index (scale 0-4), condition index (scale 0-4), faecal E.coli shedding, mucus content in faeces (days 7-9), blood samples (days 11 and 18), weight/length of duodenum/jejunum/ileum, jejunal/ileal digesta pH and contents of DM and NH3, ileal VFA, morphology, K88 receptor status. Piglets receiving 10% flaxseed and 15% oats consumed more feed (P<0.01) and grew faster (P<0.01) during the first 5 pre-challenge days, as compared to those fed a control diet (Figure 4).

Faecal shedding of E.coli K88 by the piglets highly corresponded to the ETEC K88 infection (Figure 5). Thus, this implies that our E.coli infection model was optimally targeted and effective. However, the differences among the dietary treatments were less evident.

Conclusions: Irrespective of the diet, piglets challenged with ETEC K88 grew slower (439-457 g/day) than non-challenged piglets (533 g/day), although no major clinical health problems were encountered. Daily gains of E.coli infected piglets fed 10% flaxseed and 15% oats during 18 days of this study were numerically greater (by 52 and 29 g/day, respectively) as compared to the control. Faecal consistency was similar among the treatments, irrespective of the post-challenge period. Of numerous blood indices recorded on the day 5 post-weaning, only WBC, basophiles and IgG titres were found to differ at P<0.05.

The gut wall in piglets fed flaxseed was thinner (P<0.01) as compared to the remaining treatments. Also, the number of goblet cells was lower (P<0.05) due to adding flaxseed, whereas the remaining morphological indices (villous length, crypt depth, and their ratios) differed numerically (P>0.05) only. Significant effects of the infection were also found for the jejunal length (P=0.04) and DM contents in the jejunal digesta, whereas the dietary treatments exerted minor (P>0.05) effects on the gut length, weight or digesta composition.

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