A total of 28 piglets (7 per dietary treatment) were individually allocated. There was a control diet based on dried whey, fishmeal, soybean meal and 500 g/kg cooked and flaked maize and three extra diets in which the maize was substituted (w/w) by rice that is either raw, cooked or cooked and flaked. Control pigs were fed a complex diet with a degree of starch gelatinisation (SG) of 840 g/kg. Experimental groups received the same complex diet in which maize was substituted (w/w) by rice with three different degrees of SG; 110, 520 and 760 g/kg that corresponded to raw rice and cooked rice processed under two different set of conditions.
The digestibility of dietary components, except for nitrogen, was greater for the cooked rice – than for the raw rice – and the maize diet (P<0.001). Pigs fed cooked rice had higher villous height to crypt depth ratio (P<0.001) and greater percentage of zigzag-oriented villi and lesser percentage of tongue-oriented villi (P<0.01) than pigs fed other diets. Compared with feeding maize, feeding rice improved dietary component digestibility and ileal morphology in piglets. Mild cooking of rice (SG = 520 g/kg) enhanced diet digestibility and ileum morphology. However, processing the rice to increase SG to 760 g/kg did not increase nutrient digestibility further and in fact impaired ileal morphology.
B Vicente, DG Valencia, MP Serrano, R Lazaro and GG Mateos.2009, British Journal of Nutrition, 101:1278–1281.