Cat food is food intended for consumption by cats. As with all species, cats have requirements for specific dietary nutrients, rather than ingredients. Certain nutrients, including many vitamins and amino acids, are degraded by the temperatures, pressures and chemical treatments used during manufacture, and hence must be added after manufacture to avoid nutritional deficiency. The amino acid taurine, for example, which is found within meat, is degraded during processing, so synthetic taurine is normally added afterwards. Long-term taurine deficiency resulting, for example, from feeding taurine-deficient dog food, may result in retinal degeneration, loss of vision, and cardiac damage.
History
The idea of preparing specialized food for cats came later than for dogs (see dog biscuits and dog food). This was very probably due to the idea that cats could readily fend for themselves. In 1837, a French writer critiqued this idea:
It is... thought wrongly that the cat, ill-fed, hunts better and takes more mice; this too is a grave error. The cat who is not given food is feeble and malingering; as soon as he has bitten into a mouse, he lies down to rest and sleep; while well fed, he is wide awake and satisfies his natural taste in chasing all that belongs to the rat family.
In 1844, another French writer expanded on this idea:
Normally in the country no care is taken of a cat's food, and he is left to live, it is said, from his hunting, but when he is hungry, he hunts the pantry's provisions far more than the mouse; because he does not pursue them and never watches them by need, but by instinct and attraction. And so, to neglect feeding a cat, is to render him at the same time useless and harmful, while with a few scraps regularly and properly given, the cat will never do any damage, and will render much service.
He goes on to say that it is all the more unreasonable to expect a cat to live from hunting in that cats take mice more for amusement than to eat: "A good cat takes many and eats few".
By 1876, Gordon Stables emphasized the need to give cats particular food:
If then, only for the sake of making (a cat) more valuable as a vermin-killer, she ought to have regular and sufficient food. A cat ought to be fed at least twice a day. Let her have a dish to herself, put down to her, and removed when the meal is finished. Experience is the best teacher as regards the quantity of a cat's food, and in quality let it be varied. Oatmeal porridge and milk, or white bread steeped in warm milk, to which a little sugar has been added, are both excellent breakfasts for puss; and for dinner she must have an allowance of flesh. Boiled lights are better for her than horse-meat, and occasionally let her have fish. Teach your cat to wait patiently till she is served—a spoiled cat is nearly as disagreeable as a spoiled child. If you want to have your cat nice and clean, treat her now and then to a square inch of fresh butter. It not only acts as a gentle laxative, but, the grease, combining in her mouth, with the alkalinity of her saliva, forms a kind of natural cat-soap, and you will see she will immediately commence washing herself, and become beautifully clean. (N.B.—If you wish to have a cat nicely done up for showing, touch her all over with a sponge dipped in fresh cream, when she licks herself the effect is wonderful.)
Remember that too much flesh-meat, especially liver,—which ought only to be given occasionally,—is very apt to induce a troublesome diarrhoea (looseness). Do not give your pet too many tit-bits at table; but whatever else you give her, never neglect to let her have her two regular meals.
In the same year, an ad for Spratt (better known for making dog food) said that their cat food entirely superseded "the unwholesome practice of feeding on boiled horse flesh; keeps the cat in perfect health." And in another book on cats Stables recommended the company's food:
Attend to the feeding, and, at a more than one-day show, cats ought to have water as well as milk. I think boiled lights, cut into small pieces, with a very small portion of bullock's liver and bread soaked, is the best food; but I have tried Spratt's Patent Cat Food with a great number of cats, both of my own and those of friends, and have nearly always found it agree; and at a cat show it would, I believe, be both handy and cleanly.
Spratt, which began by making dog biscuits, appears to also have been the first commercial producer of cat food.
Commercial cat food
Cat food for sale at an Istanbul animal market
Most store-bought cat food comes in either dry form, also known in the US as kibble, or wet canned form. Some manufacturers sell frozen raw diets and premix products to cater to owners who feed raw.
Dry food
Dry (extruded) cat food example
Dry food (8-10% moisture) is generally made by extrusion cooking under high heat and pressure. Fat may then be sprayed on the food to increase palatability, and other minor ingredients, such as heat-sensitive vitamins, which would be destroyed in the extrusion process, may be added.
Major brand-name dry cat food formulations consist of grain and animal material. The food labels 'premium', 'natural' or 'holistic' currently have no legal meaning. Products labeled "grain-free" may use potato or tapioca in lieu of grain. Starch allows the kibble to hold its shape.
Wet food
Wet (Canned) cat food example (Fish flakes in jelly)
Canned or wet food (75-78% moisture) generally comes in common can sizes of 3 oz (85 g), 5.5 oz (156 g), and 13 oz (369 g). It is also sold in foil pouch form by some manufacturers.
Dry vs Wet Food
Studies have not shown any difference between a dry or wet food diet for dental health. Cats generally do not 'chew' their food and usually only crunch once or twice before it is swallowed. Cats also lack the enzymes that humans possess inside their mouths to help breakdown the food they eat.
Vegetarian or vegan food
There are vegetarian and vegan cat foods available. Vegetarian cat food usually is fortified with nutrients such as taurine and arachidonic acid. Some vegetarian cat food brands are labeled by their manufacturers as meeting AAFCO's Cat Food Nutrient Profile while other manufacturers recommend their products be supplemented and not used as a complete diet.
Labeling
Further information: Pet food:Labeling and regulation
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(NRC). Certain manufacturers label their products with terms such as premium, ultra premium, natural and holistic. Such terms currently have no legal definitions.
Energy requirement
The energy requirement for adult cats range from 60-70 kcal metabolizable energy/kg body weight per day for inactive cats to 80-90 kcal/kg BW for active cats. Kittens at five weeks of age require 250 kcal/kg BW. The requirement drops with age, to 100 kcal/kg BW at 30 weeks and to the adult requirement at about 50 weeks. Gestating cats require about 90-100 kcal/kg BW and lactating cats 90-270 kcal/kg BW depending on litter size.
Nutrients and functions
Vitamin deficiencies can lead to wide 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.
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
Vegan and vegetarian diets
The feeding of vegan or vegetarian diets to cats remains controversial, even among vegan, vegetarian, animal, and scientific advocacy groups. According to the National Research Council, "Cats require specific nutrients, not specific feedstuffs.". The International Vegetarian Union, the Vegan Society and PETA are some of the organizations that support a vegan or vegetarian diet for cats. The Animal Protection Institute does not recommend a vegetarian diet for cats, and neither does the American Society for the Prevention of Cruelty to Animals (ASPCA).
Not all animal advocacy groups take a firm position either way. The Association of Veterinarians for Animal Rights (now Humane Society Veterinary Medical Association) accepts that it is possible for a plant based diet to be nutritionally adequate but stated that they "cannot at this time be reliably assured". This position was based on a study demonstrating that two commercially available vegetarian cat diets contained nutritional deficiencies. However, broad conclusions cannot be drawn from this study, because (i) it examined only two of many available diets, (ii) for one of these diets, the formulation error responsible was promptly identified and corrected,and (iii) this 2006 study is increasingly dated. Nevertheless, it remains likely that formulation errors will result in nutritional deficiencies in a wide range of commercially available diets from time to time, whether meat-based, vegetarian or vegan. Hence, regular (at least, annual) veterinary checkups of all companion animals is recommended, and brands may be occasionally varied.
Vegan activist Joanne Stepaniak wrote "... If we [believe] that it is wrong for natural vegetarians to be force-fed meat, the inverse should be equally morally objectionable".
In 2006 the first study of the health of a population of long-term vegetarian cats (most, in fact, were vegan), was published in the Journal of the American Veterinary Medical Association. Most were clinically healthy, barring minor blood value changes in three cats, who were fed partly on table scraps.
Homemade food
Further information: Raw feeding
Many pet owners feed cats homemade diets. These diets generally consist of some form of cooked or raw meat, bone, vegetables, and supplements, such as taurine and multivitamins.
bisphenol A
Recently it has been reported that food packaged in cans coated with bisphenol A has been correlated with the development of hyperthyroidism in cats.
Food allergy
Food allergy is a non-seasonal disease with skin and/or gastrointestinal disorders. The main complaint is excessive scratching (Pruritus) which is usually resistant to treatment by steroidal anti-inflammatory drugs. The exact prevalence of food allergy in cats remains unknown. 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. Allergy testing is necessary for the identification of the causative food component(s). Therapy consists of avoiding the offending food component(s).
Malnutrition
Malnutrition can be a problem for cats fed non-conventional diets. Cats fed exclusively on raw, freshwater fish can develop a thiamine deficiency. Those fed exclusively on liver may develop vitamin A toxicity. Also, exclusively meat-based diets may contain excessive protein and phosphorus whilst being deficient in calcium, vitamin E, and microminerals such as copper, zinc, and potassium. Energy density must also be maintained relative to the other nutrients. When vegetable oil is used to maintain the energy balance cats may not find the food as palatable.
Recalls
Main article: 2007 pet food recalls
The broad pet food recalls starting in March 2007 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. Overall, several major companies recalled more than 100 brands of pet foods with most of the recalled product coming from Menu Foods. The most likely cause according to the FDA is the presence of melamine in the wheat gluten of the affected foods. Melamine is known to falsely inflate the protein content rating of substances in laboratory tests. The economic impact on the pet food market has been extensive, with Menu Foods losing roughly $30 Million alone from the recall.
Nutrient chart
Association of American Feed Control Officials (AAFCO) Cat Food Nutrient Profiles a
with Role of Vitamins & Minerals
Nutrient Units
(Dry Matter Basis) Growth and
reproduction
minimum Adult
maintenance
minimum Maximum Functions Signs of deficiency/Excess
Protein % 30.0 26.0
Arginine % 1.25 1.04
Histidine % 0.31 0.31
Isoleucine % 0.52 0.52
Leucine % 1.25 1.25
Lysine % 1.20 0.83
Methionine + cystine % 1.10 1.10
Methionine % 0.62 0.62 1.50
Phenylalanine + tyrosine % 0.88 0.88
Phenylalanine % 0.42 0.42
Threonine % 0.73 0.73
Tryptophan % 0.25 0.16
Valine % 0.62 0.62
Fatb % 9.0 9.0
Linoleic acid % 0.5 0.5
Arachidonic acid % 0.02 0.02
Minerals
Calcium % 1.0 0.6
Formation of bones and teeth
Blood coagulation
Nerve impulse transmission
Muscle contraction
Cell signaling
Deficiency
Nutritional secondary hyperparathyroidism
loss of bone mineral content, which can lead to collapse and curvature of lumbar vertebrae and pelvic bones
bone pain, which can progress to pathological fractures
Excess
Depressed food intake
Decreased growth
Increased bone mineral density
Increased need for magnesium
Phosphorus % 0.8 0.5
Skeletal structure
DNA and RNA structure
Energy metabolism
Locomotion
Acid-base balance
Deficiency
Hemolytic anemia
Locomotor disturbances
Metabolic acidosis
Potassium % 0.6 0.6
Acid-base balance
Nerve-impulse transmission
Enzymatic reactions
Transport functions
Deficiency
Anorexia
Retarded growth
Neurological disorders, including ataxia and severe muscle weakness
Sodium % 0.2 0.2
Acid-base balance
Regulation of osmotic pressure
Nerve impulse generation and transmission
Deficiency
Anorexia
Impaired growth
Excessive thirst and drinking
Excessive urination
Chlorine / Chloride % 0.3 0.3
Acid-base balance
Osmolarity of extracellular fluids
Deficiency
Increased sodium concentration in renal fluid
Excess potassium excretion
Magnesium c % 0.08 0.04
Enzyme functions
Muscle and nerve-cell membrane stability
Hormone secretion and function
Mineral structure of bones and teeth
Deficiency
Poor growth
Overextension of the carpal joints
Muscle twitching
Convulsions
Excess
Urinary tract stone formation in the presence of high pH
Iron d mg/kg 80.0 80.0
Hemoglobin and myoglobin synthesis
Energy metabolism
Deficiency
Poor growth
Pale mucous membranes
Lethargy
Weakness
Diarrhea
Excess
Vomiting and diarrhea
Copper (extruded food) e mg/kg 15.0 5.0
Connective tissue formation
Iron metabolism
Blood cell formation
Melanin pigment formation
Myelin formation
Defense against oxidative damage
Deficiency
Reduced weight gain
Longer time to conceive
Copper (canned food) e mg/kg 5.0 5.0
Manganese mg/kg 7.5 7.5
Enzyme functions
Bone development
Neurological function
No studies of deficiency in cats
Zinc mg/kg 75.0 75.0 2000.0
Enzyme reactions
Cell replication
Protein and carbohydrate metabolism
Skin function
Wound healing
Deficiency
Skin lesions
Growth retardation
Testicular damage
Iodine mg/kg 0.35 0.35
Thyroid hormone synthesis
Cell differentiation
Growth and development of puppies
Regulation of metabolic rate
Deficiency
Enlargement of thyroid glands
Excess
Excessive tearing, salivation, and nasal discharge
Dandruff
Selenium mg/kg 0.1 0.1
Defense against oxidative damage
Immune response
No studies of deficiency in cats
Vitamins
Vitamin A IU/kg 9000.0 5000.0 750000.0
Vision
Growth
Immune function
Fetal development
Cellular differentiation
Transmembrane protein transfer
Deficiency
Conjunctivitis
Cataracts, retinal degeneration, and other eye problems
Weight loss
Muscle weakness
Reproductive and developmental disorders
Excess
Skeletal lesions in kittens, particularly outgrowths of the cervical vertebrae
Osteoporosis
Vitamin D IU/kg 750.0 500.0 10000.0
Maintenance of mineral status
Skeletal structure
Muscle contraction
Blood clotting
Nerve conduction
Cell signaling
Phosphorus balance
Deficiency
Rickets
Abnormalities in skeletal development
Progressive paralysis
Ataxia
Lack of grooming
Reduction in body weight and food intake
Excess
Anorexia
Vomiting
Lethargy
Calcification of soft tissues
Vitamin E f IU/kg 30.0 30.0
Defense against oxidative damage via free radical scavenging
Deficiency
Anorexia
Depression
Pain sensitivity in abdomen
Fat tissue pathology
Vitamin K g mg/kg 0.1 0.1
Activation of clotting factors, bone proteins, and other proteins
Deficiency
Prolonged blood clotting times
Hemorrhaging
Vitamin B1 / Thiamine h mg/kg 5.0 5.0
Energy and carbohydrate metabolism
Activation of ion channels in neural tissue
Deficiency
Neurological impairments including altered reflexes and convulsive seizures
Heart-rate disorders
Pathological changes in the central nervous system
Severe learning deficits
Riboflavin mg/kg 4.0 4.0
Enzyme functions
Deficiency
Cataracts
Fatty livers
Testicular atrophy
Pantothenic acid mg/kg 5.0 5.0
Energy metabolism
Deficiency
Stunted growth
Fatty changes in liver
Small bowel lesions
Niacin mg/kg 60.0 60.0
Enzyme functions
Deficiency
Anorexia
Weight loss
Elevated body temperature
Fiery red tongue, with ulceration and congestion
Vitamin B6 / Pyridoxine mg/kg 4.0 4.0
Glucose generation
Red blood cell function
Niacin synthesis
Nervous system function
Immune response
Hormone regulation
Gene activation
Deficiency
Stunted growth
Convulsive seizures
Kidney lesions
Folic Acid mg/kg 0.8 0.8
Amino acid and nucleotide metabolism
Mitochondrial protein synthesis
Deficiency
Decreased growth rate
increased iron levels in blood
Biotin i mg/kg 0.07 0.07
Vitamin B12 mg/kg 0.02 0.02
Enzyme functions
Deficiency
Weight loss
Vomiting
Diarrhea
Intestinal disorders
Cholinej mg/kg 2400.0 2400.0
Taurine (extruded food) % 0.10 0.10
Taurine (canned food) % 0.20 0.20
Nutrient Units
(Dry Matter Basis) Growth and
Reproduction
Minimum Adult
Maintenance
Minimum Maximum Functions Signs of Deficiency/Excess
NOTES
Presumes an energy density of 4.0 kcal/g ME, based on the modified Atwater values of 3.5, 8.5, and 3.5 kcal/g for protein, fat, and carbohydrate (nitrogen-free extract, NFE), respectively. Rations greater than 4.5 kcal/g should be corrected for energy density; rations less than 4.0 kcal/g should not be corrected for energy.
Although a true requirement for fat per se has not been established, the minimum level was based on recognition of fat as a source of essential fatty acids, as a carrier of fat-soluble vitamins, to enhance palatability, and to supply an adequate caloric density.
If the mean urine pH of cats fed ad libitum is not below 6.4, the risk of struvite urolithiasis increases as the magnesium content of the diet increases.
Because of very poor bioavailability, iron from carbonate or oxide sources that are added to the diet should not be considered as components in meeting the minimum nutrient level.
Because of very poor bioavailability, copper from oxide sources that are added to the diet should not be considered as components in meeting the minimum nutrient level.
Add 10 IU vitamin E above minimum level per gram of fish oil per kilogram of diet.
Vitamin K does not need to be added unless diet contains greater than 25 percent fish on a dry matter basis.
Because processing may destroy up to 90 percent of the thiamine in the diet, allowance in formulation should be made to ensure the minimum nutrient level is met after processing.
Biotin does not need to be added unless diet contains antimicrobial or antivitamin compounds.
Methionine may substitute choline as methyl donor at a rate of 3.75 parts for 1 part choline by weight when methionine exceeds 0.62 percent.
(source:wikipedia)
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