Vet360 Vol 4 Issue 4 August 2017 Vet 360

NUTRITION The Carnivore Connection to Nutrition in Cats Part 1 is a summary of the article by Debra L Zoran (DVM,PhD, DACVIM) in the Journal of the American Veterinary Medical Association Vol 221 no 11 (2002) Summarised by Dr Liesel van der Merwe Cats are unique in many ways, but especially in their nutritional biochemistry. Cats are strict carnivores and rely on nutrients in an- imal tissues to meet their requirements. The impor- tance of these nutritional differences if often underes- timated especially when cats are ill or have prolonged hypo - or anorexia. Due to their carnivorous nature cats are metabolically adapted to a higher metabolism of proteins and min- imal utilisation of carbohydrates. They are also only able to utilise starch and not soluble or insoluble fibre. Although they can use starch as a source of metabo- lisable energy they have a limited ability to down-reg- ulate protein utilisation Dry kibble requires carbohydrates for the expansion and cooking process. The limitations of these diets which also substitute animal with plant protein are be- ing realised in cats. Protein The natural feline diet is meat based and cats are adapted to use protein and fat as an energy source, with protein being utilised for maintenance of blood glucose. Adult cats require two to three more dietary animal based protein than omnivorous species. The fact that cats depend on protein for energy as well as structural and synthetic purposes is a major cause of this increased requirement. Regardless of whether cats were fed low or high amounts of proteins there was little adaptation in the enzymes responsible for protein catabolism: aminotransferases or urea cycle enzymes. Cats thus have a limited ability to adjust pro- tein utilisation to the amount of protein in their diet. This is an important reason why protein malnutrition can occur so quickly in sick, injured or anorectic cats. In addition to their need for dispensible protein, cats also need increased amounts of specific amino acids – which are contained in abundance in their natural meat based diet. The likely reason that synthetic pathways for these amino acids are not found in cats is that they are re- dundant and even energy inefficient, as the cat would take all of these in whilst consuming the natural ani- mal tissue diet (meat and fat). Utilisation of many of these amino acids is in fact higher in cats than other animals - so they have also not developed mecha- nisms to conserve them once again due to the abun- dance available in their natural diet. i. Taurine Taurine is essential for vision, cardiac muscle func- tion and proper function of the immune, reproductive and nervous systems. Cats cannot synthesis adequate quantities of taurine as the required enzymes (cysteine dioxygenase and cysteine sulfinic acid decarboxylase) are only minimally active. Additionally, cats have a constant obligatory loss of taurine through the bile because they conjugate bile acids only with tau- Issue 04 | AUGUST 2017 | 37

Vet360 Vol 4 Issue 4 August 2017 Vet 360 | Page 37