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Resistant starch can alter the intestinal nutrient availability and bulk of digesta, thereby modulating the substrate available for microbial metabolic activity along the gastrointestinal tract. This study elucidated the effect of transglycosylated starch (TGS) on the retention of digesta in the upper digestive tract, ileal flow and hindgut disappearance of nutrients, and subsequent bacterial profiles in pigs. Fourteen ileal-cannulated growing pigs were fed either the TGS or control (CON) diet in a complete crossover design. Each period consisted of a 10-d adaptation to the diets, followed by 3-d collection of faeces and ileal digesta. Consumption of TGS decreased the retention of digesta in the stomach and small intestine, and increased ileal DM, starch, Ca and P flow, leading to enhanced starch fermentation in the hindgut compared with CON-fed pigs. TGS increased ileal and faecal total SCFA, especially ileal and faecal acetate and faecal butyrate. Gastric retention time positively correlated toKlebsiella, which benefitted together withSelenomonas,Lactobacillus,Mitsuokellaand Coriobacteriaceae from TGS feeding and ileal starch flow. Similar relationships existed in faeces with Coriobacteriaceae, Veillonellaceae andMegasphaerabenefitting most, either directly or indirectly via cross-feeding, from TGS residuals in faeces. TGS, in turn, depressed genera within Ruminococcaceae,Clostridialesand Christensenellaceae compared with the CON diet. The present results demonstrated distinct ileal and faecal bacterial community and metabolite profiles in CON- and TGS-fed pigs, which were modulated by the type of starch, intestinal substrate flow and retention of digesta in the upper digestive tract.

Ca plays an essential role in bone development; however, little is known about its effect on intestinal gene expression in juvenile animals. In the present study, thirty-two weaned pigs (9·5 (sem 0·11) kg) were assigned to four diets that differed in Ca concentration (adequate v. high) and cereal composition (wheat–barley v. maize) to assess the jejunal and colonic gene expression of nutrient transporters, tight junction proteins, cytokines and pathogen-associated molecular patterns, nutrient digestibility, Ca balance and serum acute-phase response. To estimate the impact of mucosal bacteria on colonic gene expression, Spearman's correlations between colonic gene expression and bacterial abundance were computed. Faecal Ca excretion indicated that more Ca was available along the intestinal tract of the pigs fed high Ca diets as compared to the pigs fed adequate Ca diets (PZO1) and occludin (OCLN) expression, up-regulated jejunal expression of toll-like receptor 2 (TLR2) and down-regulated colonic GLUT2 expression as compared to the adequate Ca diets (PTLR2 expression and interacted (P= 0·021) with dietary Ca on colonic IL1B expression; high Ca concentration up-regulated IL1B expression with wheat–barley diets and down-regulated it with maize diets. Spearman's correlations (r>0·35; P

A high protein–low-carbohydrate diet during pregnancy can cause intra-uterine growth restriction. However, its impact during pregnancy on maternal, umbilical and fetal plasma amino acid (AA) profiles is unknown. A maternal high-protein (30 %)–low-carbohydrate (HP-LC) diet was compared with isoenergetic standard (12·1 % crude protein; ST) and low-protein (6·5 %)–high-carbohydrate (LP-HC) diets fed to nulliparous pregnant sows to examine changes in AA concentrations in maternal, venous and arterial umbilical and fetal plasma in mid and late pregnancy. At 64 and 94 days of pregnancy (dp), sows underwent Caesarean section, and maternal, umbilical and fetal plasma samples were collected. The HP-LC diet mainly affected maternal plasma AA concentrations. Plasma concentrations of Ile and Val were increased and those of Ala, Glu and Gly were decreased (P ≤ 0·05) in HP-LC compared with ST sows at 64 and 94 dp. The LP-HC diet decreased fetal plasma Glu concentration compared with the ST diet at 94 dp. Substantial AA catabolism was reflected by increased (P ≤ 0·05) maternal and fetal plasma urea concentrations with the HP-LC compared with the ST and LP-HC diets at 94 dp. Fractional placental extraction of Val was higher whereas those of Ala, Gln and Glu were lower in the HP-LC compared with the ST sows at 64 and 94 dp (P ≤ 0·05). Reduced fetal mass at 94 dp was accompanied by reduced fetal extraction of Lys and Pro in the HP-LC group (P ≤ 0·05). In conclusion, a maternal HP-LC diet during pregnancy altered maternal plasma composition of many AA and modified placental AA extraction to compensate for imbalanced maternal nutrient intake.

Relative contributions of two functional properties, viscosity and fermentability of dietary fibre, on apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), digesta passage rate, N retention and SCFA concentration have not been established. Thus, eight ileal-cannulated pigs randomised in a double 4 × 4 Latin square were fed four diets based on maize starch and casein supplemented with 5 % of actual fibre in a 2 × 2 factorial arrangement: low-fermentable, low-viscous cellulose (CEL); low-fermentable, high-viscous carboxymethylcellulose (CMC); high-fermentable, low-viscous oat β-glucan (LBG); high-fermentable, high-viscous oat β-glucan (HBG). Viscosity and fermentability interacted to affect (P P P P P R2 0·85 and 0·72, respectively; P R2 0·45 and 0·36, respectively; P