Feeding different types of cooked white rice to piglets after weaning influences starch digestion, digesta and fermentation characteristics and the faecal shedding of β-haemolytic Escherichia coli

Forty-eight, 21-d-old pigs were used to examine the effects of different types of cooked white rice on starch digestion, digesta and fermentation characteristics, shedding of β-haemolytic Escherichia coli and performance after weaning. Pigs received one of three rice-based diets: (i) medium-grain Amaroo (AM), (ii) long-grain Doongara (DOON), and (iii) waxy (WAXY). The remainder of the diet consisted predominantly of animal proteins. A fourth diet contained mainly wheat, barley and lupins (WBL). On days 1, 3, 7 and 9 after weaning, a faecal swab was taken for assessment of β-haemolytic E. coli and faecal consistency. Apparent digestibility of starch measured in the ileum 14 d after weaning was highest (P = 0·004) in AM and WAXY and lowest, but the same (P>0·05), in DOON and WBL. Starch digestibility in the rectum was highest in all rice diets (P < 0·001). Digesta viscosity was highest in pigs fed WBL in both the ileum (P < 0·001) and caecum (P = 0·027). Pigs fed rice generally had lighter (P < 0·05) gastrointestinal organs than pigs fed WBL. Performance of pigs was similar for all treatments; however, pigs fed rice-based diets had a higher (P < 0·001) carcass percentage than pigs fed WBL. Pigs fed WBL produced more acid (P < 0·05) but had lower molar proportions of acetate (P < 0·05), isobutyrate (P < 0·01) and isovalerate (P < 0·001) and a higher molar proportion of butyrate (P < 0·01) in the large intestine than pigs fed rice. Shedding of E. coli was low; however, pigs fed AM and WBL shed less E. coli than pigs fed other diets.