Obligate Carnivore (Cat Nutrition)
Definition
Obligate carnivores are animals that require parts of other animals for all of their necessary nutrients. They cannot be supplemented with all of the nutrients found in plant materials. The domestic cat, Felis catus, is the most studied of all the obligate carnivores in terms of veterinary nutrition. The feline animal is missing four crucial enzymatic or metabolic steps required by the obligate omnivores such as the dog and human for the synthesis of essential nutrients. These four steps are: 1) the synthesis of taurine from cysteine, 2) the conversion of linoleic acid to arachidonic acid, 3) the conversion of beta-carotene to vitamin A, and 4) the synthesis of niacin from tryptophan.
Expanded Body
DOMESTIC CATS (Felis catus) are known to be descended from the African wildcat (Felis silvestris lybica). This is a strict, prey-based predator that roamed the arid regions of the world, and from a nutritional perspective, would have gained little from the consumption of carbohydrates from plants. Four fundamental metabolic restrictions were therefore imposed upon the domestic cat by its wild ancestors, restrictions that are firmly in place today and are the basis for the feline being an omnivorous animal that is quite different from other members of this group. The four restrictions are: (1) the absolute inability of the domestic cat to synthesize taurine from the cysteine and methionine in its diet; the minimum required levels of taurine in commercial feline diets are therefore 0.1% DM on a dry matter basis for dry foods and 0.17% DM for wet foods (AAFCO 2003); (2) the inability of the domestic cat to convert the linoleic acid in its diet to the longer-chain arachidonic acid; preformed arachidonic acid, in the form of animal fat, is therefore required in the diet; (3) the very limited ability of the domestic cat to convert beta-carotene from plants in its diet to retinol (vitamin A); preformed vitamin A, in the form of liver or fish oil, is therefore required in the diet; (4) the severe restriction upon the synthesis of niacin by the domestic cat from tryptophan in its diet; large amounts of preformed niacin in the form of meat are therefore required in the diet, the minimum required level being 60 mg/kg DM (AAFCO 2003).
Limitations of using plant based / grain dominant ingredients in formulating complete and balanced diets for cats are immense. Even when total protein is bumped up to meet the percentage value of complete protein, it is bound to be incomplete. As per Cornell University College of Veterinary Medicine’s 2024 Feline Nutrition Guide, 85% of cats on homemade or vegan diets are found to have taurine deficiency within 6– 6 – 24 months unless supplemented. According to FSSAI Standard 2.2.10, Minimum AAFCO taurine levels must be specified and ensured on all Cat Foods sold in India. Thus all certified brands (Whiskas, Me-O, Drools and Royal Canin grain inclusive formulations also) are meeting minimum taurine levels for their feline consumers.
Quick Facts
| Metric | Value |
|---|---|
| Taurine (Dry Food Min) | 0.1% DM |
| Taurine (Wet Food Min) | 0.17% DM |
| Vitamin A Source | Must be preformed |
| Arachidonic Acid | Must be from animal fat |
| Niacin Min | 60 mg/kg DM |
OBLIGATE CARNIVORE NUTRITIONAL REQUIREMENTS VS DOGS
| Nutrient / Pathway | Cats (Obligate Carnivore) | Dogs (Omnivore) | Implication for Cat Food |
|---|---|---|---|
| Taurine | Cannot synthesise — must obtain from diet | Can synthesise endogenously | Must be added to cat food |
| Vitamin A | Cannot convert beta-carotene to retinol | Can convert from plants | Must come from liver, fish oil |
| Arachidonic Acid | Cannot convert from linoleic acid | Can convert efficiently | Must come from animal fat |
| Niacin | Very limited synthesis from tryptophan | Adequate synthesis | High niacin in meat required |
| Protein Requirement | 26% DM (adult minimum) | 18% DM (adult minimum) | 44% higher base requirement |
Related Terms
Faq
Q: Can cats survive on vegetarian or vegan cat food?
Vegan diets, with or without supplements of taurine, arachidonic acid, retinol (Vitamin A) and niacin, whether sourced from animal or not, cannot support a long-term healthy cat. Even when supplied in adequate quantities to the diet, these nutrients cannot be effectively derived from non-animal sources to support life of a healthy obligate carnivore. Taurine deficiency has been reported in 85% of the cats fed unsupplemented vegan diets for 6–24 months. The deficiency results in irreversible dilated cardiomyopathy (DCM and retinal degeneration. All vegan and vegetarian cat foods sold in India must have AAFCO certification ‘complete and balanced’ which implies that all the obligate-carnivore-specific nutrients have been synthetically added to the diet.
Key Takeaways
- Cats are obligate carnivores which means that 4 essential nutrients (taurine, arachidonic acid, vitamin A, niacin) must be provided in their diet from animal sources.
- Taurine deficiency causes irreversible DCM and retinal degeneration in cats. The minimum amount of taurine in a dry cat food as required by AAFCO is 0.1% on a DM basis (minimum).
- 85% of the cats on unsupplemented completely plant-based (vegan) diets in a study from Cornell Vet (2024) developed taurine deficiency within 6–24 months on these diets.
- FSSAI Standard 2.2.10 requires all the cat food sold in India to be formulated as per minimum taurine levels as specified by AAFCO.
