Abstract
Within Canada, agronomic conditions determine cultivated crops. In Eastern Canada, crops are mostly corn and soybean. In Western Canada, crop rotations exists with wheat, barley, and oats as cereal grains, canola, and pulse grains such as field pea and lentil. Seeds of these crops together with their co-products may serve as plant-based ingredients to provide starch, fiber, protein, and fat for kibble production. From coast-to-coast, products from raised fish, poultry and livestock may serve as animal-based ingredients to provide protein and fat. While animal and plant protein differ in AA profile and digestibility, changes in functionality beyond gluten content are limited. In contrast, fatty acid profiles differ in omega 3 to 6 ratio among plant and animal sources. Analyses of fiber and starch have focused on assessing quantity; however, both have a range of functional properties. Fibers ranging from low to high viscous affect digesta flow and from slowly to rapidly fermentable alter production of volatile fatty acid (VFA) serving as energy for the gut or whole body. Hulls of cereal grains and pulse grains are low viscous and slowly fermentable. In contrast, fibers such as β-glucan in barley and oats and oligosaccharides in pulse grains are rapidly fermentable and may serve as prebiotic. Cereal grains tend to have a faster rate and total extent of starch digestion and thus glycemic index than pulse grains due to more amylose in pulse grains. Consequently, pulse grains may provide less digestible starch than cereal grains and more resistant starch that is fermented, thereby changing starch from glucose source into VFA source. Resistant starch thus basically acts as dietary fiber. However, differences in starch digestion among grains are reduced with extrusion of kibbles. Functional characteristics of fiber and starch can be altered using ingredient selection and should be considered in petfood formulation.
Keywords: Digestive physiology, Fiber, Starch