Although Pet food companies use important amounts of protein and carbohydrate sources, little scientific information was published about digestibility and metabolizable energy of these ingredients for dogs and cats. Rice and corn have been considered the better starch sources for these animals, but it was presented that sorghum is well digestible for dogs too. When interpreting scientific data the reader needs to consider the differences among studies that evaluated flour or refined starch or the usage of ground grain, as employed by pet food companies. Besides of digestibility and energy content, starch interferes on dogs glycemic response's, which presents an opportunity to select low insulin and glucose response starch sources to diets designed to animals in special conditions. Due to high protein requirements, these ingredients are important in food formulation for dogs and cats. Protein sources of animal origin have greater variation in chemical composition, quality and digestibility than vegetable proteins. Animals' meals can have high levels of ash, limiting the inclusion of these ingredients in pet food formulation. On the other hand vegetable proteins can have antinutritional factors that must be inactivated during manufacturing. It was demonstrated that vegetable proteins can have good digestibility and metabolizable energy for dogs and cats. Their utilization in food formulation can help in reduction of diet' ash level, control of food's base excess and keeping good diet digestibility. Micronized whole soybean and corn gluten meal with 60% protein are highlighted, showing good digestibility and energy content's values for dogs and cats. In relation to dry animal proteins, poultry by product meal have better digestibility and metabolizable energy values.
canine; digestibility; feline; ingredient; nutrition; starch
