Amino acid and mineral concentrations of whole grains and grain byproducts used in pet foods

Abstract Text: Whole grains may be valuable components of canine diets, due to the functional ingredients, such as dietary fiber and β-glucans, or the amino acids (AA) and minerals they provide; however, the use of whole grains in pet food has not been thoroughly evaluated.  Our objective was to measure the AA and mineral concentrations of various whole grains, processed grains, and grain byproducts that may be incorporated into dog food.  Thirty-one grain samples, including:  rice samples (brown rice, rice, rice bran, and rice flour); barley samples (barley flake, cut barley, ground pearled barley, malted barley, whole pearled barley, pearled barley flakes, and steamed rolled barley); oat samples (groats, ground oatmeal, ground steamed groats, instant oats, oat bran #1, oat bran #2, oat fiber, oat flour, quick oats, regular rolled oats, steamed rolled oat groats, and steel cut groats); and miscellaneous cereals and pseudocereals (conventional hulled millet, conventional whole millet, conventional quinoa, organic spelt hull pellets, potato flake, sorghum, whole wheat, and whole yellow corn) were analyzed.  Total essential (0.65 – 7.51% DMB) and individual AA concentrations were highly variable among ingredients tested:  Arginine (0.01 – 1.38% DMB), Histidine (0.02 – 0.47% DMB), Isoleucine (0.07 – 0.62% DMB), Leucine (0.15 – 1.49% DMB), Lysine (0.06 – 0.88% DMB), Methionine (0.03 – 0.36% DMB), Phenylalanine (0.08 – 0.77% DMB), Threonine (0.05 – 0.66% DMB), Tryptophan (<0.04 – 0.20% DMB), and Valine (0.09 – 0.96% DMB).  Of the ingredients tested, oat fiber had the lowest concentrations of most essential AA and rice bran had the highest concentrations of most essential AA.  Calcium, phosphorus, and magnesium concentrations ranged from 0.0 – 2.22% DMB, 0.04 – 2.03% DMB, and 0.03 – 0.88% DMB, respectively, with rice bran having the highest concentrations of all three minerals.  Based on our compositional analysis, whole grains and grain byproducts vary greatly in AA and mineral content.  Although these ingredients are commonly used in canine diets, more research is needed to test the effects of feeding whole grains to dogs.

Keywords: Whole grains, Amino acids, Minerals