cat food

Cat enjoying a mix of wet (canned) and dry cat food

Cat food is food manufactured for consumption by cats. Although cats are obligate carnivores, most commercial cat food contains both animal and plant material, supplemented with vitamins, minerals and other nutrients. Cat food is formulated to address the specific nutritional requirements of cats, in particular containing the amino acid taurine, as cats cannot thrive on taurine-deficient food and go blind when fed with dog food, for example.^[1]

Commercial cat food

Cat food for sale at an Istanbul animal market

Most store-bought cat food comes in either dry form, also known as kibble, or wet canned form. Some manufacturers sell frozen raw diets and premix products to cater to owners who feed raw.

Major brand-name dry cat food manufacturers often use primarily grain-based ingredients like corn and rice with meat by-products or animal digest making up the meat ingredients. Some manufacturers offer 'premium', 'natural' or 'holistic' formulas that are by-product free and contains less or no grains. Grain-free dry diets still contain carbohydrates, from sources such as potato or tapioca as the starch in those ingredients is needed to allow the kibble to hold its shape. Cats have no metabolic need for carbohydrates as the feline system prefers to create glucose from protein.

Dry food

Dry (Extruded) cat food example

Dry food is generally made by extrusion cooking under high heat and pressure. It may then be sprayed with fat to increase palatability and other ingredients to complete its composition.

Pet owners often prefer dry cat food due to the convenience and price. Besides usually being significantly cheaper, dry cat food can also be left out for the cat to eat at will over the course of several days; whereas, canned or raw cat food spoils or becomes unappetizing after several hours.

Dry food is recommended by some based on the idea that cats break apart dry foods with their teeth, which causes the food to scrape off dental calculus.^{[citation needed]} The degree of benefit this provides has been disputed in recent years.^{[citation needed]}

Many dry foods use meals as protein source, such as meat meal, chicken meal, fish meal, or corn gluten meal. This allows manufacturers to produce cheaper foods. Since the occurrence of BSE infection through contaminated meat and bone meal, the use of meat meal in pet foods has been prohibited in parts of the world (e.g. Japan and France) but is still common practice in other parts (e.g. USA). Comparative studies conducted by Japanese researchers have shown that meat meal is superior to the other protein meal sources in terms of dry-matter digestibility and nutritional value for cats, while corn gluten meal is the least nutritional.^[2][3][4]

The same studies showed that cats fed with these dry food diets excreted alkaline urine. Urine pH has been implicated in the formation of struvite crystals in feline urolithiasis, and many dry food manufacturers address this by adding urine-acidifying ingredients to their food. However, this practice may lead to the formation of calcium oxalate stones, therefore water intake rather than urine pH appears to be the most crucial factor for the prevention and treatment of feline stones.^[5]

Wet food

Wet (Canned) cat food example (Fish flakes in jelly)

Canned or wet food generally comes in common can sizes of 3 oz (85 gm), 5.5 oz, and 13 oz. It is also sold in foil pouch form by some manufacturers.

Owners and veterinarians who recommend a diet consisting largely or entirely of canned, homemade or raw cat food point to higher water content of such food and the increased total water consumption in comparison to a dry food diet as an important health benefit.^{[citation needed]} Wet food also generally contains significantly less grain and other carbohydrate material, although many are made with fish ingredients.

Canned cat foods in pop-top containers may play a role in the development of hyperthyroidism in cats^[6]. This may be due to bisphenol A used in the pop-top can coating leaching into the food.^[7] Some cat foods also contain goitrogens, such as soybean products.

In general, canned, homemade, or raw foods are thought to either help treat or noticeably reduce the likelihood of numerous health issues including urinary tract disorders^[8][9], diabetes, chronic renal failure^[10], constipation (sometimes leading to megacolon), and obesity. ^{[citation needed]}

Homemade food

Many pet owners feed cats homemade diets. These diets generally consist of some form of cooked meat or raw meat, ground bone, pureed vegetables, taurine supplements, and other multivitamin supplements. Although cats are naturally resistant to many of the bacteria that raw meats contain, meat can sometimes also contain parasites and other harmful organisms and for this reason raw meat is sometimes frozen for periods of time before being used.^{[citation needed]} Some pet owners use human vitamin supplements, and others use vitamin supplements specifically engineered for cats. Veterinarians sometimes recommend including digestive enzyme supplements in a homemade diet. Some pet food manufacturers offer packaged versions of a raw food diet that closely resembles such homemade diets. These packaged versions are generally kept frozen, with individual portions being thawed in advance.

See also: Raw feeding

Vegetarian or vegan food

Vegetarian or vegan cat food has been available for many years, and is targeted primarily at vegan and vegetarian pet owners. Most veterinarians recommend against vegetarian diets for cats, as cats are obligate carnivores and require nutrients (including taurine, arachidonic acid, vitamin A, vitamin B12 and niacin) found in meat sources that cannot be obtained in sufficient amount in plant sources, although many can be synthesized. One study evaluated cats fed commercial and homemade vegetarian diets. The study found that all cats had serum cobalamin (vitamin B12) levels within the reference range and 3 of 17 cats had serum taurine values below the reference range.^[11]

Another study evaluated two vegan diets for nutritional adequacy. The study concluded that the two vegan diets analyzed did not meet the AAFCO minimal nutrient profile for cat diets. The authors recommended that these vegan diets should not be used as a sole source of nutrition for cats.^[12]

Even when adequately supplemented, some claim vegetarian diets present other risks, such as urine acidity problems, which are less common in meat-based foods.^{[citation needed]} A few vegetarian cat food brands are labelled by their manufacturers as meeting AAFCO's Cat Food Nutrient Profile while other manufacturers recommend their products to be supplemented and not used as a standalone. Many pet owners have caused their cats to become malnourished when they do not follow the recommendation and mistakenly assume that the latter food is nutritionally complete.^{[citation needed]}

Nutrient profiles and functions

In the United States, cat foods labeled as "complete and balanced" must meet standards established by the Association of American Feed Control Officials (AAFCO) either by meeting a nutrient profile or by passing a feeding trial. Cat Food Nutrient Profiles were established in 1992 and updated in 1995 by the AAFCO's Feline Nutrition Expert Subcommittee. The updated profiles replaced the previous recommendations set by the National Research Council.

Products that are formulated with ingredients to meet the established nutrient profile would include the following statement. "(Name of product) is formulated to meet the nutritional levels established by the AAFCO Cat Food Nutrient Profiles."

Products that are substantiated to be "complete and balanced" by feeding trials will have the statement "animal feeding tests using AAFCO procedures substantiate that (name of product) provides complete and balanced nutrition." The protocol requires that 6 out of 8 cats complete a 26 week feeding trial without showing clinical or pathological signs of nutritional deficiency or excess. The cats' general health is evaluated by a veterinarian before and after the test. Four blood values, hemoglobin, packed cell volume, serum alkaline phosphatase and serum albumin are measured after the trial and the average values of the test subjects must meet minimum levels. No animal is allowed to lose more than 15% of its starting weight.

There are two separate nutrient profiles - one for "growth and reproduction" and one for "adult maintenance". The nutritional adequacy statement would include info on which life stages the product is suitable. A product labeled as "for all life stages" must meet the more stringent nutrient profile for "growth and reproduction". Products labeled as "intended for intermittent or supplemental feeding" do not meet either profiles. Maximum levels of intake of some nutrients have been established because of concerns with overnutrition.

Vitamins are organic compounds that take part in a wide range of metabolic activities. Vitamin deficiencies can lead to widely ranging clinical abnormalities that reflect the diversity of their metabolic roles. Twelve minerals are known to be essential nutrients for cats. Calcium and phosphorus are crucial to strong bones and teeth. Cats need other minerals, such as magnesium, potassium, and sodium, for nerve impulse transmission, muscle contraction, and cell signaling. Many minerals only present in minute amounts in the body, including selenium, copper, and molybdenum, act as helpers in a wide variety of enzymatic reactions.^[13]

The table below lists the AAFCO nutritional profiles for cat foods along with the roles of vitamins and minerals in cat nutrition according to the National Research Council.

Diet and disease

Food allergy

Food allergy is a non-seasonal disease with skin and/or gastrointestinal disorders. The main complaint is Pruritus, which is usually resistant to treatment by steroidal anti-inflammatory drugs. The exact prevalence of food allergy in cats remains unknown. There is no breed, sex or age predilection, although some breeds are commonly affected. Before the onset of clinical signs, the animals have been fed the offending food components for at least two years, although some animals are less than a year old. In 20 to 30% of the cases, cats have concurrent allergic diseases (atopy / flea-allergic dermatitis). A reliable diagnosis can only be made with dietary elimination-challenge trials. Provocation testing is necessary for the identification of the causative food component(s). Therapy consists of avoiding the offending food component(s).^[15]

Malnutrition

Cats fed exclusively on raw, freshwater fish can develop a thiamine deficiency.Those fed exclusively on liver may develop vitamin A toxicity. Malnutrition has been seen in cats fed "natural", "organic", or "vegetarian" diets produced by owners with good intentions, and most published recipes have been only crudely balanced (by computer) using nutrient averages. Because the palatability, digestibility, and safety of these recipes have not been adequately or scientifically tested, it is difficult to characterize all of these homemade diets. Generally, most formulations contain excessive protein and phosphorus and are deficient in calcium, vitamin E, and microminerals such as copper, zinc, and potassium. Also, the energy density of these diets may be unbalanced relative to the other nutrients. Commonly used meat and carbohydrate ingredients contain more phosphorus than calcium. Homemade feline diets that are not actually deficient in fat or energy usually contain a vegetable oil that cats do not find palatable; therefore, less food is eaten causing a calorie deficiency. Rarely are homemade diets balanced for microminerals or vitamins. Owner neglect is also a frequent contributing factor in malnutrition.^[16]

Recalls

Main article: 2007 pet food recalls

The 2007 pet food recalls involved the massive recall of many brands of cat and dog foods beginning in March 2007. The recalls came in response to reports of renal failure in pets consuming mostly wet pet foods made with wheat gluten from a single Chinese company, beginning in February 2007. After more than three weeks of complaints from consumers, the recall began voluntarily with the Canadian company Menu Foods on March 16 2007, when a company test showed sickness and death in some of the test animals. Soon after, there were numerous media reports of animal deaths as a result of kidney failure, and several other companies who received the contaminated wheat gluten also voluntarily recalled dozens of pet food brands.

By the end of March, veterinary organizations reported more than 100 pet deaths amongst nearly 500 cases of kidney failure, with one online database self-reporting as many as 3,600 deaths as of April 11. As of April 8, Menu Foods has confirmed only about 16 deaths. The U.S. Food and Drug Administration refuses to estimate the amount of sick or dead because there is no centralized government records database of animal sickness or death in the United States as there are with humans (such as the Centers for Disease Control). As a result, many sources speculate that the actual number of affected pets may never be known and experts are concerned that the actual death toll could potentially reach into the thousands.

Overall, several major companies have recalled more than 100 brands of pet foods, with most of the recalled product coming from Menu Foods. Although there are several theories of the source of the agent causing sickness in affected animals, with extensive government and private testing and forensic research, to date, no definitive cause has been isolated. As of April 10, the most likely cause, according to the FDA, though not yet proven, is indicated by the presence of melamine in wheat gluten in the affected foods. The Chinese company behind the contaminated wheat gluten has initially denied any involvement in the contamination, but is cooperating with Chinese and American investigators.

In the United States, there has been extensive media coverage of the recall. There has been widespread public outrage and calls for government regulation of pet foods, which had previously been self-regulated by pet food manufacturers. The United States Senate held an oversight hearing on the matter by April 12. The economic impact on the pet food market has been extensive, with Menu Foods losing roughly $30 Million alone from the recall. The events have caused distrust of most processed pet foods in some consumers.

References

External links

• From the U.S. Food and Drug Administration - Center For Veterinary Medicine
  • Pet Foods
  • Information For Consumers - FDA's Regulation Of Pet Food
  • Information For Consumers - Information On Marketing A Pet Food Product
  • Information For Consumers - Interpreting Pet Food Labels
  • Information For Consumers - Interpreting Pet Food Labels - Special Use Foods
  • Vegetarian Diets For Pets?
• The Vegetarian Society UK on concerns relating to a vegetarian diet for cats
• From Max's House Feline Medical And Behavior Database
  • Feline Nutrition
  • Cat Food Nutrient Profiles
  • Dry food v/s canned (wet) food
  • Dispelling The Myth That Pets Are Used In Pet Foods
• From Animal Protection Institute
  • Get The Facts - What's Really In Pet Food

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