Changes

The term “protein quality” is used to describe the ability of a given plant or animal protein to provide adequate levels of essential amino acid(s) in order to support biological functions, such as growth or reproduction. Protein quality is determined by the composition of amino acids, and the [[Nutrition Glossary#Digestibility|digestibility]] and [[Nutrition Glossary#Bioavailability|bioavailability]] of amino acids within a given protein type. Protein digestibility can be adversely affected by dysfunction in any of the organs responsible for protein digestion and absorption (e.g., disorders of the stomach, pancreas, small intestine). In  healthy animals protein digestibility is influenced by size in dogs<ref>Hannah SS, et al. Digestibility of diet in small and large breed dogs. Vet Clin Nutr 1995;2:145.</ref><ref>Nery J, et al. Influence of dietary protein content and source on fecal quality, electrolyte concentrations, and osmolarity, and digestibility in dogs differing in body size. J Anim Sci 2010;88:159-169.</ref> and decrease with age<ref>Teshima E, et al. Nutrient digestibility, but not mineral absorption, is age-dependent in cats. JAPAN (Berl) 2010;94:e251-258.</ref>. Additionally, cats protein digestibility of certain protein sources is lower compared to dogs<ref>de-Oliveira DL, et al. Digestibility for dogs and cats of meat and bone meal processed at two different temperature and pressure levels. JAPAN(Berl) 2012;96:1136-1146.</ref>. Dietary factors known to influence protein digestibility include:  

The term “protein quality” is used to describe the ability of a given plant or animal protein to provide adequate levels of essential amino acid(s) in order to support biological functions, such as growth or reproduction. Protein quality is determined by the composition of amino acids, and the [[Nutrition Glossary#Digestibility|digestibility]] and [[Nutrition Glossary#Bioavailability|bioavailability]] of amino acids within a given protein type. Protein digestibility can be adversely affected by dysfunction in any of the organs responsible for protein digestion and absorption (e.g., disorders of the stomach, pancreas, small intestine). In  healthy animals protein digestibility is influenced by size in dogs<ref>Hannah SS, et al. Digestibility of diet in small and large breed dogs. Vet Clin Nutr 1995;2:145.</ref><ref>Nery J, et al. Influence of dietary protein content and source on fecal quality, electrolyte concentrations, and osmolarity, and digestibility in dogs differing in body size. J Anim Sci 2010;88:159-169.</ref> and decrease with age<ref>Teshima E, et al. Nutrient digestibility, but not mineral absorption, is age-dependent in cats. JAPAN (Berl) 2010;94:e251-258.</ref>. Additionally, cats protein digestibility of certain protein sources is lower compared to dogs<ref>de-Oliveira DL, et al. Digestibility for dogs and cats of meat and bone meal processed at two different temperature and pressure levels. JAPAN(Berl) 2012;96:1136-1146.</ref>. Dietary factors known to influence protein digestibility include:  

#The presence of anti-nutritive properties within certain ingredients (e.g., trypsin inhibitors found in uncooked legumes)<ref>Gilani GS, et al. Impact of antinutritional factors in food proteins on the digestibility of protein and the bioavailability of amino acids and on protein quality. B J Nutr 2012;108:S315-S332.</ref>;  

#The presence of anti-nutritive properties within certain ingredients (e.g., trypsin inhibitors found in uncooked legumes)<ref>Gilani GS, et al. Impact of antinutritional factors in food proteins on the digestibility of protein and the bioavailability of amino acids and on protein quality. B J Nutr 2012;108:S315-S332.</ref>;  

#The formation of Maillard reaction LINK TO GLOSSARY products (cross-linkages between sugars and amino acids)<ref>van Rooijen C, et al. The Maillard reaction and pet food processing: effects on nutritive value and pet health. Nutr Res Rev 2013;26:130-148.</ref>; and  

#The formation of [[Nutrition Glossary#Maillard Reaction|Maillard reaction]] products (cross-linkages between sugars and amino acids)<ref>van Rooijen C, et al. The Maillard reaction and pet food processing: effects on nutritive value and pet health. Nutr Res Rev 2013;26:130-148.</ref>; and  

#High temperature and pressure effects on protein structures<ref>Johnson ML, et al. Effects of species raw material source, ash content, and processing temperature on amino acid digestibility of animal by-product meals by cecectomized roosters and ileally cannulated dogs. J Anim Sci 1998;76:1112-1122.</ref><ref>Larsen JA, et al. 2010 Bioavailability of lysine for kittens in overheated casein is underestimated by the rat growth assay method. JAPAN (Berl) 2010;94:e102-108.</ref><ref>Kerr KR, et al. Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets. J Anim Sci 2012;90:515-522.</ref>. The digestibility of protein is typically lower in plant-compared to animal-derived proteins<ref>Neirinck K, et al. Amino acid composition and digestibility of four protein sources for dogs. J Nutr 1991;121:S64-S65.</ref>. Feeding diets with a high soluble fiber content<ref>Muir HE, et al. Nutrient digestion by ileal cannulated dogs as affected by dietary fibers with various fermentation characteristics. J Anim Sci 1996;74:1641-1648.</ref><ref>Silvio J, et al. Influences of fiber fermentation on nutrient digestion in the dog. Nutr 2000;16:289-295.</ref><ref>Harper EJ. The effect of fiber on nutrient availability in cats of different ages. Vet Clin Nutr 1995;3:114.</ref> or with larger volumes of poorly digestible carbohydrate<ref name="NRC"/> will also result in a lower apparent protein digestibility in both dogs and cats.

#High temperature and pressure effects on protein structures<ref>Johnson ML, et al. Effects of species raw material source, ash content, and processing temperature on amino acid digestibility of animal by-product meals by cecectomized roosters and ileally cannulated dogs. J Anim Sci 1998;76:1112-1122.</ref><ref>Larsen JA, et al. 2010 Bioavailability of lysine for kittens in overheated casein is underestimated by the rat growth assay method. JAPAN (Berl) 2010;94:e102-108.</ref><ref>Kerr KR, et al. Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets. J Anim Sci 2012;90:515-522.</ref>. The digestibility of protein is typically lower in plant-compared to animal-derived proteins<ref>Neirinck K, et al. Amino acid composition and digestibility of four protein sources for dogs. J Nutr 1991;121:S64-S65.</ref>. Feeding diets with a high soluble fiber content<ref>Muir HE, et al. Nutrient digestion by ileal cannulated dogs as affected by dietary fibers with various fermentation characteristics. J Anim Sci 1996;74:1641-1648.</ref><ref>Silvio J, et al. Influences of fiber fermentation on nutrient digestion in the dog. Nutr 2000;16:289-295.</ref><ref>Harper EJ. The effect of fiber on nutrient availability in cats of different ages. Vet Clin Nutr 1995;3:114.</ref> or with larger volumes of poorly digestible carbohydrate<ref name="NRC"/> will also result in a lower apparent protein digestibility in both dogs and cats.