Biological response of commercial high fiber breakfast cereals consumed in northwestern of Mexico in growing rats

Abstract

The importance of dietary fiber and the contribution of fiber‐rich commercial breakfast cereals to the Mexican diet have long been recognized. The objective of this study was to biologically evaluate three commonly consumed high fiber commercial breakfast cereals selected from the local market, two different brand of whole wheat and wheat bran based, which differed from each other in terms of size and quantity of bran, and one rolled whole oat cereal, using Sprague dawley rats. Biological indices determined were food efficiency ratio (FER), net protein ratio (NPR) and in vivo digestibility. In vivo digestibility of diet based on oat cereal was 83 – 85%, superior to diets containing wheat bran, presenting values from 62 – 64% of apparent nitrogen digestibility, and 66 – 67% of true nitrogen digestibility, which corresponds to up to71% of casein digestibility. NPR of diet based on oat cereal was 3.2 also superior to diets containing wheat bran, presenting values from 1.8 – 2, which corresponds to up to 46% of casein. Results showed that commercial breakfast cereals with different type and level of dietary fiber showed significant differences in protein quality. This study indicates that fiber in wheat bran products reduces nitrogen utilization in growing rats by causing increases in excretion of endogenous and dietary fecal nitrogen. It also shows that some fibers alter the biological value of the nitrogen that is absorbed.