New study reveals fiber composition of rice co-products

Rice co-products in the diet of pigs add fat and fiber, but too much fiber can reduce the absorption of energy and digestibility. A recent study from the University of Illinois characterizes the chemical composition of fiber in rice and rice co-products, which could lead to dietary interventions to improve digestibility.

"Due to the low fermentability of rice fibers, there is a high potential for increased digestibility if we can find specific enzymes that can help degrade them." For pigs, the most important thing is to be able to obtain more energy from each ingredient ". Hans Stein, Professor, Department of Animal Sciences and Division of Nutritional Sciences, University of Italy and co-author of the study published in Science and technology of animal feed.

A former doctoral student working with Stein, Gloria Casas, badyzed the carbohydrate composition of several ingredients – brown rice, broken rice, whole rice bran, defatted rice bran and rice milling – in a laboratory in Denmark. She also badessed the digestibility of each ingredient by simulating the environments of the stomach, small intestine and large intestine of pork, including fermentability by intestinal microbes.

The starch, cellulose, lignin and fiber content varied considerably, among other specific carbohydrate fractions, but for all ingredients the primary carbohydrates were arabinoxylated.

"Arabinoxylans are relatively complex fibers composed mainly of two sugars, arabinose and xylose, although there are many others as well," he explains. "This is true for all rice co-products, but the relationship between arabinose and xylose differs according to the ingredients, and this ratio, to some extent, influences the functionality of the fibers."

The simulated digestibility (in vitro) was higher for brown rice and broken rice than for all other coproducts, which Stein and Casas expected, since the whole rice bran, the fat-free rice bran and the rice miller's food was much richer in insoluble fiber. The results confirm previous digestibility studies conducted by researchers with the same ingredients in pigs.

Stein notes that the results do not apply only to pigs.

"Humans are consuming rice and rice bran all over the world, and knowing the fiber composition of these products will help us determine which intestinal microbes are affected," he said. "In humans, one of the major problems in terms of nutrition in our part of the world is that we are not getting enough fiber.If we consume these fibers, what will be the consequences for our intestinal microbes? ? "