Wheat bran and middlings, a byproduct of flour milling, are common ingredients in less expensive pet foods. They are composed of the bran coats of the wheat, which is actually a healthy fraction and what we benefit from when we eat whole wheat products. In comparison to the wheat kernel used for white flour, wheat bran and middlings have nearly double the amount of fatty acids, fiber and mineral.
The following are definitions from Kansas State University’s extension service:
• “Wheat Middlings consist of fine particles of wheat bran, wheat shorts, wheat germ, wheat flour, and some of the offal from the “tail of the mill.” This product must be obtained in the usual process of commercial milling and must contain not more than 9.5% crude fiber. (Proposed 1959, Adopted 1960.) IFN 4-05-205 Wheat flour byproduct less than 9.5% fiber
• Wheat Bran is the coarse outer covering of the wheat kernel as separated from cleaned and scoured wheat in the usual process of commercial milling. (Adopted prior to 1928.) IFN 4-05-190 Wheat bran.”
In general, pet owners with an interest in nutrition are told that it’s bad to see this by product in a pet food, because it is a cheap filler. One problem that would occur with high levels would be an elevated fiber content which reduces digestibility. On the other hand, this fiber contains fructooligosaccharides that benefits gut motility and microbial populations.
But a legitimate concern is that ‘messing with mother nature’ – taking grains apart into fractions then putting them into a food artificially, is chancey and a bad idea compared to just using whole grain. And of course, the processors that mill so much white flour that the bran and middlings are available for mass production of cheap pet foods – well, perhaps we should decline to be part of the demand that creates that supply. My two cents – maybe we should stick with whole grain ingredients.
Reference: Aldrich G. Cheap filler or nutritious fiber? Petfood Industry, January 2009 p. 42-43