Recent Advances in the Nutrition and Metabolism of Dogs and Cats

Domestic dogsDog (facultativeFacultative carnivoresCarnivore) and catsCat (obligateObligate carnivoresCarnivore) have been human companionsCompanion for at least 12,000 and 9000 years, respectively. These animalAnimal species have a relatively short digestive tract but a large stomachStomach volume and share many common features of physiological processes, intestinal microbes, and nutrient metabolismMicrobes. The tasteTaste buds of the canineCanine and felineFeline tongues can distinguish sour, umami, bitter, and salty substances. DogsDog, but not catsCat, possess sweet receptors. α-Amylase activity is either absent or very low in canineCanine and felineFeline saliva,Saliva and is present at low or substantial levels in the pancreatic secretions of catsCat or dogsDog, respectively. Thus, unlike catsCat, dogsDog have adapted to high-starchStarch rations while also consuming animalAnimal-sourced foodsFood. At metabolic levels, both dogsDog and catsCat synthesize de novo vitaminVitamin C and many amino acids (AAs, such as Ala, Asn, Asp, Glu, Gln, Gly, Pro, and Ser) but have a very limited ability to form vitaminVitamin D3. Compared with dogsDog, catsCat have higher requirementsRequirement for AAs, some B-complex vitaminsVitamin, and cholineCholine; greater rates of gluconeogenesisGluconeogenesis; a higher capacity to tolerate AA imbalances and antagonism; a more limited ability to synthesize arginineArginine and taurine from glutamine/proline and cysteineTaurine, respectively; and a very limited ability to generate polyunsaturatedPolyunsaturated fatty acidsFatty acid (PUFAs) from respective substrates. Unlike dogs, cats cannot convert either β-carotene into vitaminVitamin A or tryptophan into niacin. DogsDog can thrive on one large mealMeal daily and select high-fatFat over low-fatFat dietsDiet, whereas catsCat eat more frequently during light and dark periods and select high-proteinProtein over low-proteinProtein dietsDiet. There are increasing concerns over the healthHealth of skinSkin, hairHair, boneBone, and jointsJoints (specialized connective tissues containing large amounts of collagenCollagen and/or keratinKeratin); sarcopeniaSarcopenia (age-related losses of skeletal-muscle mass and functionFunction); and cognitiveCognitive functionFunction in dogsDog and catsCat. Sufficient intakes of proteinogenic AAs and taurineTaurine along with vitaminsVitamin, mineralsMineral, and PUFAs are crucial for the normal structures of the skinSkin, hairHair, boneBone, and jointsJoints, while mitigating sarcopeniaSarcopenia and cognitiveCognitive dysfunctionDysfunction. Although petPet owners may have different perceptions about the feedingFeeding and managementManagement practice of their dogsDog and catsCat, the healthHealth and well-being of the companionCompanion animalsAnimal critically depend on safe, balanced, and nutritive foodsFood. The new knowledge covered in this volume of Adv Exp Med Biol is essentialEssential to guide the formulation of pet foodsPetfood to improve the growthGrowth, developmentDevelopment, brainBrain functionFunction, reproductionReproduction, lactationLactation, and healthHealth of the companionCompanion animalsAnimal.