The canine ancestral diet
With an ever-increasing interest in companion animal nutrition and a growing skepticism of the
“scientifically developed” kibble products thrust upon consumers in supermarkets, pet stores and
veterinary clinics, let’s take a few minutes to question: How did our carnivorous companions survive and
thrive before the advent of kibble extrusion technology?
The true science behind raw feeding
In this era of evidence-based medicine, a criticism that is often levelled at feeding a raw, speciesappropriate, prey-based diet to pets, is that there is a lack of scientific research to support the practice. The purpose of this document is to highlight the research that supports feeding pets their evolutionary diet. The research covers three important aspects of feeding a raw prey based diet:
• The nutrient content of raw food.
• The non-nutritive aspects of raw food (including dental health and behavioural enrichment).
• Food safety issues or raw-feeding (for human and pet health).
It is imperative that we define the nutrient profiles of cats and dogs based on current evidence, but we should look further than just nutrient profiles and include the non-nutritive aspects of food. Finally, the evidence available must support the safety of a raw food diet for pets and their owners.
The nutritional adequacy of home-prepared and commercial diets for dogs
Maintaining the health of dogs and cats by feeding wholesome nutritional diets is an important component of responsible pet ownership. Numerous improvements in companion animal nutrition have resulted in a wide array of foods providing complete and balanced nutrition. In spite of these developments, some pet owners prefer preparing food at home for their animals (1). Although owners generally have good intentions, some of them may lack the scientific knowledge or other resources to recognize important nutritional needs of their pets. Thus the potential for nutrient deficiencies, excesses and imbalances exists.
Amylase activity and its implications for dog domestication, diet and diabetes
High amylase activity in dogs is associated with a drastic increase in copy numbers of the gene coding for pancreatic amylase, AMY2B, that likely allowed dogs to thrive on a relatively starch-rich diet during early dog domestication. Although most dogs thus probably digest starch more efﬁciently than do wolves, AMY2B copy numbers vary widely within the dog population, and it is not clear how this variation affects the individual ability to handle starch nor how it affects dog health. In humans, copy numbers of the gene coding for salivary amylase, AMY1, correlate with both salivary amylase levels and enzyme activity, and high amylase activity is related to improved glycemic homeostasis and lower frequencies of metabolic syndrome. Here, we investigate the relationship between AMY2B copy numbers and serum amylase activity in dogs and show that amylase activity correlates with AMY2B copy numbers. We then describe how AMY2B copy numbers vary in individuals from 20 dog breeds and ﬁnd strong breed-dependent patterns, indicating that the ability to digest starch varies both at the breed and individual level. Finally, to test whether AMY2B copy number is strongly associated with the risk of developing diabetes mellitus, we compare copy numbers in cases and controls as well as in breeds with varying diabetes susceptibility. Although we see no such association here, future studies using larger cohorts are needed before excluding a possible link between AMY2B and diabetes mellitus.
Future aspects and perceptions of companion animal nutrition and sustainability
Companion animals play an important role in our lives and are now considered to be and treated as family members in a majority of households in the United States. Because of the high number of pets that now exist, an increasingly stronger pet–human bond, and the importance placed on health and longevity, the pet food industry has realized steady growth over the last few decades. Despite past successes and opportunities that exist in the future, there are also challenges that must be considered. This review will present a brief overview of the current pet food industry and address some of the key issues moving forward. In regards to companion animal research, recent advances and future needs in the areas of canine and feline metabolism, aging, clinical disease, and the gut microbiome using molecular and highthroughput assays; chemical, in vitro, and in vivo testing of feed ingredients; and innovative pet food processing methods is discussed. Training the future workforce for the pet food industry is also of great importance. Recent trends on student demographics and their species and careers of interest, changing animal science department curricula, and technology’s impact on instruction are provided. Finally, the sustainability of the pet food industry is discussed. Focus was primarily placed on the disconnect that exists between opinions and trends of consumers and the nutrient recommendations for dogs and cats, the desire for increasing use of animalbased and humangrade products, the overfeeding of pets and the pet obesity crisis, and the issues that involve the evaluation of primary vs. secondary products in terms of sustainability. Moving forward, the pet food industry will need to anticipate and address challenges that arise, especially those pertaining to consumer expectations, the regulatory environment, and sustainability. Given the already strong and increasingly dynamic market for pet foods and supplies, an academic environment primed to supply a skilled workforce, and continued industry support for basic and applied research initiatives, the future of the pet food industry looks very bright.
Emerging advancements in canine and feline metabolism and nutrition
The pet industry continues to grow in both developed and developing countries. According to the 2015-2016 APPA National Pet Owners Survey, 65% of US households own a pet,which encompasses 85.8 million pet cats and 77.8 million pet dogs. In Europe alone, there are another estimated 81 million dogs and 63 million cats, and this market is expected to have a compound annual growth rate of 4.4%, as compared to a 3.5% projected growth rate in the USA.
The evolutionary basis for the feeding behavior of domestic dogs and cats
The dentition, sense of taste and meal patterning of domestic dogs and cats can be interpreted in terms of their descent from members of the order Carnivora. The dog is typical of its genus, Canis, in its relatively unspecialized dentition, and a taste system that is rather insensitive to salt. The preference of many dogs for large infrequent meals reflects the competitive feeding behavior of its packhunting ancestor, the wolf Canis lupus. However, its long history of domestication, possibly 100,000 years, has resulted in great intraspecific diversity of conformation and behavior, including feeding. Morphologically and physiologically domestic cats are highly specialized carnivores, as indicated by their dentition, nutritional requirements, and sense of taste, which is insensitive to both salt and sugars. Their preference for several small meals each day reflects a daily pattern of multiple kills of small prey items in their ancestor, the solitary territorial predator Felis silvestris. Although in the wild much of their food selection behavior must focus on what to hunt, rather than what to eat, cats do modify their food preferences based on experience. For example, the “monotony effect” reduces the perceived palatability of foods that have recently formed a large proportion of the diet, in favor of foods with contrasting sensory characteristics, thereby tending to compensate for any incipient nutritional deficiencies. Food preferences in kittens during weaning are strongly influenced by those of their mother, but can change considerably during at least the first year of life.
Key bacterial families are related to the digestion of protein and energy in dogs
Background. Much of the recent research in companion animal nutrition has focussed on understanding the role of diet on faecal microbiota composition. To date, diet induced changes in faecal microbiota observed in humans and rodents have been extrapolated to pets in spite of their very different dietary and metabolic requirements. This lack of direct evidence means that the mechanisms by which microbiota influences health in dogs are poorly understood. We hypothesised that changes in faecal microbiota correlate with physiological parameters including apparent macronutrient digestibility. Methods. Fifteen adult dogs were assigned to two diet groups, exclusively fed either a premium kibbled diet (kibble; K; n=8) or a raw red meat diet (meat; M; n=7) for nine weeks. Apparent digestibility of macronutrients (protein, fat, gross energyand dry matter), faecal weight, faecal health scores, faecal VFA concentrations and faecal microbial composition were determined. Datasets were integrated using mixOmics in R. Results. Faecal weight and VFA levels were lower and the apparent digestibility of protein and energy were higher in dogs on the meat diet. Diet significantly affected 27 microbial families and 53 genera in the faeces. In particular, the abundances of Bacteriodes, Prevotella, Peptostreptococcus and Faecalibacterium were lower in dogs fed the meat diet, whereas Fusobacterium, Lactobacillus and Clostridium were all more abundant. Discussion. Our results show clear associations of specific microbial taxa with diet composition. For example, Clostridiaceae, Erysipelotrichaceae and Bacteroidaceae were highly correlated to parameters such as protein and fat digestibility in the dog. By understanding the relationship between faecal microbiota and physiological parameters we will gain better insights into the effects of diet on the nutrition of our pets.