Tiki PetsCat Treats: Tuna Flavor

A fish used mostly in cat foods, where its strong flavor is the point. Tuna is a good protein and a source of omega-3 fats. Two cautions apply to tuna fed often: it is higher in mercury than smaller fish, and cats can become fixated on it and refuse other foods. Both cautions apply to the cat eating tuna every day, and much less to tuna as one ingredient in a complete food fed in rotation.

A staple of grain-free recipes, supplying starch, fiber and plant protein. Peas were common in the diets examined in a federal investigation into heart disease in dogs; the investigation did not establish a cause and no ingredient was banned. Pea protein high on a list can inflate the protein number with a plant source. Pea allergy is rare. Not a problem, but worth noticing when it appears in several forms in one recipe.

Starch from the cassava root, used to bind kibble and as a carbohydrate source, especially in grain-free foods. It is nearly pure starch with little protein, fiber or micronutrients, and it is one of the least likely ingredients to trigger an allergy. A food that leans on tapioca for carbohydrate is getting easy digestibility and little else from it, which is fine as long as the rest of the recipe carries the nutrition.

Rendered fat, a concentrated energy source and the main supply of linoleic acid, an essential fatty acid for skin and coat. Rendered fat carries very little protein, so many chicken-allergic pets tolerate it, but not all do, and a strict elimination diet avoids it. Usually preserved with mixed tocopherols. Not a quality concern; a good fat source.

The most common protein in pet food, and for dogs one of the most common food allergens, with beef and dairy. If chicken is what your pet reacts to, it hides everywhere: chicken fat, chicken broth, chicken meal, natural flavor. On a label, chicken listed first is weighed with its water still in, so a food leading with fresh chicken often has less chicken protein than one leading with chicken meal. Neither is better; they are different measures.

Oil pressed from salmon, added for the omega-3 fats EPA and DHA that support skin, coat and joints. It does the same job as generic fish oil but names its source, which helps if your pet reacts to other fish. Like all fish oils it spoils easily and needs a preservative, usually mixed tocopherols. The levels used in food are a modest supplement, well below a therapeutic dose.

A vegetable used mainly as a source of soluble fiber for stool quality, and for label appeal. Amounts in a complete food are small. Not an allergen of concern and not a meaningful protein or calorie source.

Almost always rosemary extract, used as a natural antioxidant to keep fats fresh, usually alongside mixed tocopherols. The amounts are tiny. A persistent internet claim links rosemary to seizures in dogs; there is no published evidence for it at food levels. If your dog has epilepsy, ask your neurologist rather than avoiding foods on this basis alone.