Cat food is food for consumption by cats. Cats have specific requirements for their dietary nutrients. 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 in meat, is degraded during processing, so synthetic taurine is normally added afterwards. Long-term taurine deficiency may result in retinal degeneration, loss of vision, and cardiac arrest.
Video Cat food
History
The idea of preparing specialized food for cats came later than for dogs (see dog biscuits and dog food). This was likely due to the idea that cats could readily fend for themselves. In 1837, a French writer Mauny de Mornay 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 sickly; 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 advertisement 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.
During the 19th century and early 20th centuries, meat for cats and dogs in London, frequently horse meat, was sold from barrows (hand-carts) by itinerant traders known as Cats' Meat Men.
Maps Cat food
Natural diet
Cats are obligate carnivores--that is, they are true carnivores and depend upon the nutrients present in animal flesh for their dietary needs. Even domesticated cats will relish freshly killed meat from rodents, rabbits, amphibians, birds, reptiles and fish, but cats are also opportunistic feeders and will readily take cooked food as well as dried cat food when offered, if that food is palatable. The natural diet of cats therefore does not include any vegetable matter, although cats have been known to eat certain plants and grasses occasionally, usually as an emetic.
Cats cannot synthesize some essential nutrients required for survival, including the amino acids taurine and arginine, so these nutrients must be sourced from fresh meat in the natural diet. Cats lack the specific physiology to extract nutrients efficiently from plant-based materials, and require a high protein diet, which is why high energy meats from freshly-killed prey are optimal foods.
Commercial cat food
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 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. Dry food is most often packed in multi-wall paper bags, sometimes with a plastic film layer; similar bag styles with film laminates or coextrusions are also used.
Wet food
In the United States, canned or wet food (75-78% moisture) generally comes in aluminum or steel cans in 3 oz (85 g), 5.5 oz (156 g), and 13 oz (369 g) sizes. It is also sold in foil pouch form.
Vegetarian or vegan food
Even though cats are obligate carnivores, there are vegetarian and vegan cat foods available. Vegetarian cat food must be fortified with nutrients such as taurine and arachidonic acid that cats cannot synthesize from plant materials. Some vegetarian cat food brands in the USA are labeled by their manufacturers as meeting AAFCO's Cat Food Nutrient Profile.
Low protein
Low protein diets are not as popular with consumers than high protein diets. Low protein diets are frequently associated with renal care formulas and other prescribed therapeutic diets.
Raw food
Raw feeding is providing uncooked ingredients to cats. Most of the diet will consist of animal-based ingredients, though fruits, vegetables and supplements are often added. Commercial raw food is mainly sold in three formats: fresh, frozen and freeze-dried. Thawing and rehydration are necessary before feeding frozen and freeze-dried food respectively. Many available commercial diets are AAFCO certified in meeting the nutrient requirements of the cat. Some diets may be formulated for all life stages or they can also be AAFCO certified for adult maintenance or growth and gestation/lactation. Many people feed their cats raw food believing that it mimics the prey diet that wild cats would consume. Firm believers in raw diets report that they bring health benefits such as a shiny coat, cleaner teeth, improved immunity, energy and body odors to their cats, although no scientific evidence exists to prove these claims.
Commercial raw diets can undergo High Pressure Pasteurization (HPP), a process which kills bacteria and pathogens, including salmonella, using high water pressure. This technique is USDA approved and allows raw food to remain uncooked while greatly improving its safety and shelf-life. However, every year, many commercial raw pet foods are recalled due to various bacterial contamination, implying that feeding raw comes with a risk.
Weight Management
Weight control simply means ensuring an energy balance: energy in equals energy out. Weight gain in any animal means there is an energy imbalance: more energy is being consumed than is being expended in exercise and other functions. A weight management diet is designed to allow fewer calories to be consumed in a larger volume of food, allowing for less risk of an energy imbalance. But the cat needs to take enough exercise too.
Adult cats should be fed a diet that has been formulated for maintenance, while at the same time it should be fed according to preference and body condition. Cats generally prefer to eat smaller meals more frequently, which tends to lead to less weight gain compared to cats that are fed free-choice food. Meanwhile, some cats adapt to free-choice feeding and can maintain normal body weight without experiencing weight gain. In general, indoor cats have less opportunity or need for exercise than outdoor cats, and as a result indoor cats are much more prone to weight gain. For indoor cats, there are a variety of choices to promote exercise, including various cat toys designed to simulate chase and play behaviours. Overall, if an adult cat cannot maintain normal body condition on a free-choice feeding diet, despite exercise levels, portion-controlled feeding is recommended. Many pet cats are fed energy-dense, high carbohydrate diets, which provide the cat with much more energy than needed. This is a major issue with indoor cats as it has been shown to lead to obesity. To prevent cats from becoming overweight, owners should be more inclined to implement weight control diets, which provide the cat with nutrient-dense, low energy ingredients. Studies show that cats fed lower energy diets had significantly reduced incidence of obesity, as the typical indoor pet cat does not need more energy than their resting energy requirement. For an average cat weighing 10-11 pounds (about 5 kg), they would have a resting energy requirement of 180-200 kcal/day.
Along with energy input and output, specific nutrients can be important in weight control diets. Fiber is one important component in weight control, with various benefits. A source of soluble and fermentable fiber helps to increase the movement of digesta through the gut and decrease gastric emptying. This helps to increase satiety in cats, potentially decreasing feeding rates and voluntary energy consumption. Fermentable fiber promotes healthy mucosa and commensal bacterial growth, and improved digestion/nutrient absorption. Prebiotic fibers like fructooligosaccharides (FOS) and mannonoligosaccharides (MOS) decrease the number of pathogenic bacteria and increase the number of beneficial bacteria in the gut. They also help to maintain microbial balance and a healthy immune system. Fiber is fermented in the colon to produce short-chain fatty acids which can be used as an energy source. Fermentable fiber has been demonstrated to enhance general health and decrease inflammation. Furthermore, non-fermentable fiber is critical to the formation of well-formed stool, and has been known to increase diet bulk while decreasing caloric density. Insoluble fiber has been proposed to regulate appetite by releasing hormones that reduce hunger. Sources of fiber commonly added in weight management cat food include beet pulp, barley, psyllium and cellulose.
Another nutrient important for weight control diets is protein and its component amino acids. Felines, being obligate carnivores, require a natural diet of strict animal products which consists of protein and fat (i.e. muscle, organs and animal tissue). Dietary protein supplies amino acids that can be utilized and metabolised as energy over fat when provided, even though protein is not stored in the body the same way as fat. Dietary fat is more efficiently converted to body fat than protein; if an animal is consuming more than its energy requirement and if the excess energy is provided by fat, more weight will be gained than if the excess calories are coming from protein. Dietary protein also improves satiety during feed, resulting in decreased overconsumption of food. The protein content of the diet is a key factor in building and maintaining lean body (muscle) mass, which is an important aspect of weight control. Lean body mass maintenance is regulated by protein intake, but more importantly is regulated by exercise. Limited protein and amino acids in the diet will limit lean body mass growth, but exercise or lack of exercise will allow growth or shrinking of muscle. Successful weight control involves maintenance of healthy adipose tissue levels, but most importantly maintenance of lean body mass. Lean muscle is the driver of basal energy metabolism and aids in the use of energy. When sufficient levels of fat are provided, fat will be used by the body as an energy source, but only when there are insufficient levels of protein.
An important amino acid that is incorporated many weight loss/weight control diets is L-carnitine. This is a vitamin-like substance that is found in animal protein, and is the only form found in nature as well as being the only biologically active form. It can be found in ingredients commonly used in more commercial pet foods, but specifically weight management/weight loss diets. L-carnitine is involved in many biological pathways, more specifically fatty acid metabolism, allowing for the conversion of long-chain fatty acids into energy. The introduction of L-carnitine ensures rapid transport and oxidation of fatty acids as well as efficient usage of dietary fatty acids and protein. Supplementary L-carnitine is used more often in weight loss diets, since its benefits mainly involve fatty acid metabolism to control weight loss. However, since weight control is, in essence, a prevention stage in overall weight management, it still has value in weight control diets in preserving and building lean body mass and inhibiting the storage of excess dietary fat. The majority of studies focusing on supplementary L-carnitine use look at its benefits for weight loss, including its effect on metabolic rate and fatty acid oxidation. At the same time, these studies still show similar results that prove their effects of controlling fatty acid metabolism for weight control, to avoid the need for weight loss diets.
Packaging and labeling
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. However, "While most of the food supplied comes from within the US, the FDA ensures that standards are met within our borders even when components come from countries with less stringent levels of safety or label integrity."
Dry cat food (kibble) is most often packed in multi-wall paper bags, sometimes with a plastic film layer; similar bag styles with film laminates or coextrusions are also used. Wet cat food is often packed in aluminum cans or steel cans. Packaging regulations for cat food are often very similar to corresponding regulations for human foods.
Energy requirement
The energy requirements for adult cats range from 60-70 kcal metabolizable energy/kg body weight (BW) 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 approximately 90-100 kcal/kg BW, up to 1.5 times the energy required of normal adult maintenance. Lactating cats require 90-270 kcal/kg BW depending on litter size and they require between 2 and 2.5 times the energy needed for normal adult maintenance.
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
Low protein therapeutic diets and relation to the kidneys
Therapeutic diets with low protein have been adopted by a number of big pet food manufacturers with the goal of supporting renal health for cats with chronic kidney disease (CKD). Chronic kidney disease or CKD is a highly prevalent condition in the feline population and is most common in the aging and older domesticated feline. It has been shown that the lifespan of cats experiencing CKD can be extended by as much as 2 years when receiving therapeutic diets rather than regular maintenance diets. The normal functions of the kidneys are to control a normal fluid balance and to excrete waste products from the blood into the urine. One of the biggest concerns associated to CKD is to reduce the amount of stress put on the kidneys to process and excrete nitrogenous wastes from the body. Low protein diets are a good choice for cats experiencing CKD as it lowers the amount of nitrogenous waste in the body helping to decease the strain put on the kidneys. Nitrogenous wastes are produced by the body when amino acids obtained from the digestion of protein are metabolized to make energy. The exact level of protein that is needed for therapeutic CKD diets is unclear, as sufficient protein in needed for maintenance while still offering a lower nitrogen level for the kidneys.
Low protein diets can be formulated as a wet or dry food, with the main difference being the moisture content. These diets are formulated specifically to support the kidneys and urinary tract and also to help prevent the progression of CKD. There are certain dietary parameters that these diets follow on top of low protein such as low phosphorus, high energy density, a higher fat content and inclusion of omega-3 fatty acids to aid the kidneys in different ways. Formulating the diet to have low phosphorus is very important as restricting the amount in the diet has been proven to decrease the progression of CKD. The reason that plasma phosphorus concentration should be kept low for low protein therapeutic diets is because phosphorus can be deposited into soft tissues and become mineralized which can cause kidney damage. Formulating these diets with higher amounts of fat is important to make sure the food is palatable in the absence of protein and promote an increased caloric intake. The higher fat content will also spare the use of protein for energy and help decrease stress on kidney. This inclusion of higher fat content also increase the energy density of the food which is important for cats with decreased appetites. Omega-3 fatty acids are included in therapeutic diets because of their anti-inflammatory properties to aid the diseased kidneys.
Low protein diets and relation to the liver
Low protein diets should not be fed to cats with the liver condition known as hepatic encephalopathy because severe protein restriction can be detrimental to animals with this condition. Cats with this condition should be fed a diet with high quality protein sources that have adequate amounts of the amino acids taurine and arginine.
High energy diets
A high energy diet is generally high in fat. Compared to other macronutrients such as carbohydrates and protein- fat provides much more energy, at 8.5kcal/g. High energy diets generally have a fat content greater than 20% on a dry matter basis. Feeding a high energy diet is appropriate for cats who are undergoing growth, recovering from illness, are pregnant or lactating, as their energy requirements are higher than maintenance requirements. A lactating and gestating cat requires a nutrient dense and highly digestible diet to withstand the high levels of stress being placed on her body. These conditions are found in cat food that is formulated for growth, performance, or high energy during all life stages.
To maintain a neutral energy balance and thus maintain body weight energy intake should increase with energy expenditure. Studies that relate the number of meals offered to cats per day to their daily activity levels have been met with conflicting results. It has been shown that cats offered four meals a day or a random number of meals a day have similar energy levels, greater than those fed only one meal per day. It has been postulated that this increased energy level could be due to purported spikes in activity before being fed known as food anticipatory activity. Other studies have found increasing the amount of feedings per day in female cats may actually decrease their daily activity levels. The age, sex, and whether cats are intact or have been spayed/neutered are all factors controlling activity level.
As cats age from the adult to senior life stages there is evidence that their metabolic energy requirements may increase. These increases have been shown to appear markedly after 12 years of age and even more so after 13 years of age. Other evidence suggests that metabolic energy needs are not dissimilar between life stages. Furthermore, it has been shown that cats greater than 12 years of age have a greater likeliness of being underweight than any other age group and thus to maintain and appropriate body condition score a high calorie diet may be appropriate as a treatment for weight loss. Weight loss can occur when the cat enters a negative energy balance such as when metabolic energy requirements are increased without dietary caloric compensation. It has also been demonstrated that as cats age their ability to digest and thus absorb dietary fats and proteins decreases. In order to maintain a neutral energy balance in this case a high calorie diet may be recommended.
A cat's nutritional needs should be met during both pregnancy and lactation as these are strenuous times in terms of energy consumption. During pregnancy a cat should gain 38% of their body weight by the time they are ready to give birth. A queen's diet should contain 4000 kcal/ ME per day while pregnant and then during lactation the cat should be consuming 240 - 354 kcal/ME / kg of body weight . Studies show that increasing the intake of food for a pregnant animal in order to help it gain weight can have negative effects. It is acknowledged that rather than increasing intake, feeding a highly energy dense food is a way to ensure the queen gets adequate energy, being aware to meet all nutrient requirements.
It has been found that nutritional support consistent with the resting energy requirement (RER) soon after operation or the onset of illness decreases the mortality rate and the duration of hospitalization in cats. A recovering cat requires sufficient energy (calories), as well as an increased need for protein and fats. Critical care diets are formulated to be highly palatable and digestible, as well as high energy density. This limits the volume of food required to be consumed to meet the RER. This type of high energy diet has proven to be very important in the nutritional support of post-operative and ill cats.
Vegan and vegetarian diets
Vegetarian or vegan cat food has been available for many years, and is targeted primarily at vegan and vegetarian pet owners. While a small percentage of owners choose such a diet based on its perceived health benefits, the majority do so due to ethical concerns. Despite this, most vegans who feed their cats a vegan diet believe that a vegetarian diet is healthier than a conventional diet. There is much controversy over feeding cats a vegetarian diet. While there is anecdotal evidence that cats do well on vegetarian food, studies on commercial and homemade vegetarian cat foods have found nutritional inadequacies.
As obligate carnivores, cats require nutrients (including arginine, taurine, arachidonic acid, vitamin A, vitamin B12 and niacin) found in meat sources that cannot be obtained in sufficient amount in plant sources. Vegetarian pet food companies attempt to correct these deficiencies by supplementing their products with synthetically produced nutrients. According to the United States National Research Council, "Cats require specific nutrients, not specific feedstuffs."
Cats on a vegan diet can develop abnormally alkaline (high pH) urine due to the more alkaline pH of plant-based proteins in comparison to the acidic pH of meat-based foods which cats have evolved to eat. When the urine pH becomes too alkaline, there is an increased risk of formation of struvite (also known as magnesium ammonium phosphate) bladder crystals and/or stones. Calcium oxalate stones can also occur, but these do not occur if the urine is too alkaline, but rather if it is too acidic. Such stones can create irritation and infection of the urinary tract and require veterinary treatment.
Organizations that advocate vegan or vegetarian diets for people have split opinions regarding vegetarian or vegan cat food. The International Vegetarian Union, the Vegan Society and PETA are some of the organizations that support a vegan or vegetarian diet for cats. On the other hand, the Vegetarian Society suggests people "consider carefully" and that many cats will not adjust to a vegetarian diet. They provide a list of necessary nutrients that will need to be supplemented with a recommendation to consult a veterinarian or animal nutritionist for those who want to try. The Animal Protection Institute also does not recommend a vegetarian diet for cats and cautions that dietary deficiencies may take months or years to develop and may be untreatable. They do not recommend relying on supplements because they may not contain necessary co-factors and enzymes and have not been studied for long term implications. The animal welfare organization American Society for the Prevention of Cruelty to Animals, although suggesting a supplemented vegetarian diet for dogs, recommends against a vegetarian and vegan diets for cats. 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 in August 2006 that such diets "cannot at this time be reliably assured". This position was based on a 2004 study demonstrating that of two commercially available vegetarian cat diets tested against the AAFCO standard, both were nutritionally deficient. The formulation error in one of these diets was promptly identified and corrected. 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.
Even when adequately supplemented, vegetarian diets may present other risks, such as urine acidity problems. While there are anecdotal reports linking a vegetarian diet with urinary tract problems, no documented case report or study exist. One vegan cat food manufacturer has stated that "because of the relative acidity of meat to vegetable protein, some vegan cats suffer from [Urinary tract problems]." A quarter of cat owners who feed their cats a vegetarian diet perceive feline lower urinary tract disease as a health risk of such a diet.
In 2006, the first study of the health of a population of long-term vegetarian cats was published in the Journal of the American Veterinary Medical Association. Most of the cats were fed a commercially available vegan diet, though 35% were allowed outdoors. The study consisted of telephone questionnaires of the caregivers of 32 cats, and analysis of blood samples from some of them. The blood samples were tested for taurine and cobalamin deficiencies. Cobalamin levels were normal in all cats. Taurine levels were low in 3 out of 17 cats tested, but not low enough to be considered clinically deficient. 97% of the caregivers perceived their cats to be healthy, including those with low taurine levels.
Formulation of a nutritionally adequate vegan cat diet has its limitations. Reoccurring errors during formulation include insufficient protein content, insufficient calcium and phosphorus, along with an unbalanced calcium phosphorus ratio which strays from the ideal ratio of 0.9 to 1.1:1. This is in addition to commonly occurring deficiencies of taurine, arachidonic acid, sodium, vitamin A, vitamin B12 as well as trace minerals.
The reason for these dietary essential nutrients can be found in the physiology section of the Cat page.
Protein and fat content in a vegan cat diet can be balanced through the inclusion of tofu and yeast. Over the counter supplementation of vitamins and minerals in some cases may not meet nutrient requirements as they come in varying amounts. As vegan diets are mainly composed of plants sources, some vitamins and minerals may be deficient as plant sources do not provide adequate quantities. For instance, plant materials do not provide the preformed vitamin A which cats cannot synthesize, therefore supplementation is needed. As mentioned previously, arginine is a dietary requirement of cats, as it plays a critical role in bodily functions (refer to the physiology section in the Cat page). Some ingredients that may be seen in vegan cat diets that provide arginine, are pumpkin seed, almond, soya flour, lentil seeds and oat flakes (see table one). [1] The addition of arachidonic acid to cat foods typically comes from animal based sources. In vegan cat diets, arachidonic acid can be added through the inclusion of algal biomass or seaweed. However, providing excessive amounts of seaweed to the diet can be detrimental, as seaweed is very high in selenium allowing for toxicity to be possible. A vitamin D3 source, Lanolin, a constituent of sheep's wool, is often used as a form of supplementation for this vitamin. However, due to its animal origin this would not be appropriate for supplemental use in a vegan cat diet so a synthetic form of vitamin D3 is required. Vegan vitamin D3 can be synthesized through the combination of the ingredients lichen, chicory extract and chamomile extract. Some vegan sources with high niacin content are Brewer's yeast, oats, wheat flours, sunflower seeds and sesame seeds. AAFCO requires cat food to have 60 mg of niacin per kg of cat food on a dry matter basis. Taurine can be biosynthesized or can be obtained in the diet by eating animal sources for food or algae. For cats, taurine is an essential amino acid acid as they cannot biosynthesize it from the amino acids methionine or cysteine, therefore, they must obtain it endogenously. A synthetic form of taurine must be supplemented in adequate amounts in a vegan cat diet (as plant sources do not have taurine) to ensure taurine deficiencies do not occur (refer to the physiology section on the Cat page).
Low protein diets
Protein content between cat foods can vary anywhere from a low protein content of 26% to a content as high as 50% or above. The National Research Council (NRC) recommends protein content for cat diets is to be around 20% for adult maintenance and 21.3% for growth and reproduction The Association of American Feed Control Officials (AAFCO) recommendations however suggest a higher protein level of 26% for adult maintenance and 30% for growth and reproduction.
Cats are obligate carnivores and require protein in their diet as an important component in energy metabolism and maintenance of lean body muscle. Cats are greatly adapted to a high protein diet since they utilize protein as their main energy source, keeping carbohydrate utilization very minimal. In addition, cats will continue to metabolize protein even through protein deficiency by catabolizing lean body muscle. More specifically cats like most mammals, require the appropriate dietary amino acid balance to supply the essential amino acids, which are used for a multitude of body functions. It is crucial for low protein diets to meet AAFCO recommendations to ensure nutrient requirements are met.
In general, lower protein diets tend to consist of a greater carbohydrate content, which means a potentially higher glycemic response in cats. Glycemic response refers to the response of glucose concentrations in the blood after a meal. Hexokinase is the enzyme cats use for metabolizing glucose because they do not possess the more efficient enzyme glucokinase. Cats are susceptible to high prolonged postprandial glucose and insulin periods with high glucose peaks, resulting from the carbohydrate content of the diet. The degree of glucose peaks and the duration of the elevated glucose levels ultimately depends on the glycemic index of the carbohydrates used in the diet. Typically a diet of low protein is replaced with added carbohydrate content. In some cases, fat can be added to lower protein diets in order to increase the energy density of the food product .
A nutritional balance of amino acids is important in low protein cat diets as cats are highly sensitive to deficiencies in arginine, taurine, methionine, and cysteine. Therefore, supplementation of these essential amino acids is important and commonly found in cat foods. The supplementation of polyunsaturated omega-3 fatty acids is common in products with lower protein as it plays a positive role in protecting the kidneys which is an issue for many cats on a low protein diet . Similarly, mineral composition is important and low protein diets result in a low phosphorus content that benefits the renal care and prevention of kidney disease. .
Benefits to low protein diets
Feeding a lower protein content can help lower the amount of calcium being excreted in the feces and urine. It has been observed that urinary calcium concentrations and fecal calcium excretion is related to increasing protein concentration in the diet. Increasing calcium in the urine and feces can indicate increased calcium mobilization (for example of bone) within a cat instead of increased intestinal calcium absorption. Lower protein fed to cats can also decrease renal oxalate excretion, and therefore, decrease renal oxalate and calcium concentrations to support the decrease in urinary calcium concentrations, which contributes to the decrease in urinary relative saturations with calcium oxalate and can decrease the probability of a cat developing calcium oxalate stones.
A lower amount of harmful bacteria is accumulated with a lower protein diet which helps to increase the amount of positive bacteria present in the gut.
Consequences to low protein diets
In low protein diets, if the protein source isn't a high quality protein such as an animal based protein, cats, especially kittens have been shown to develop retinal degeneration due to a taurine deficiency, an essential amino acid for cats that is derived from animal protein.
Since cats have such a high protein requirement, lower protein content, and thus lower amino acid concentrations, in the diet have been linked to health defects such as lack of growth, decreased food intake, muscle atrophy, hypoalbuminemia, skin alterations, and more. Cats on lower protein diets also have increased probability of not only losing weight, but also losing lean body mass.
Low protein diets that are high in carbohydrates have been found to decrease glucose tolerance in cats. With a decreased glucose tolerance, clinical observations have confirmed that cats consuming large proportions of metabolizable energy in the form of carbohydrates rather than protein, have increased chance of developing hyperglycaemia, hyperinsulinemia, insulin resistance, and obesity.
Cats have a high priority for gluconeogenesis in order to provide energy for tissues like the brain. With this high priority for gluconeogenesis, the rate at which it operates doesn't change despite having a low protein diet. Despite now being able to down-regulate gluconeogenesis, cats are able to regulate their amino acid catabolism in response to a low protein diet, probably by increasing the synthesis of enzyme proteins without altering the catalytic rate. This collectively can make a cat "wasteful" of amino acids supplied, when supplied with a low protein diet
Low protein diets have been shown to lower the levels of eosinophilic granulocytes within cats, which impacts the overall function of the immune system.
Homemade food
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. Homemade diets either follow a recipe, such as the BARF diet which provides a series of options for the pet owner to make, or rely on the constant rotation of ingredients to meet nutrient requirements. A study was conducted that analyzed 95 homemade BARF diets and found that 60% of these were nutritionally imbalanced in either one or a combination of calcium, phosphorus, vitamin D, iodine, zinc, copper, or vitamin A content.
Bisphenol A
A 2004 study reported that food packaged in cans coated with bisphenol A is correlated with the development of hyperthyroidism in cats.
Food allergy
Main Article: Allergies in cats
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
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 alone losing roughly $30 million from the recall. Some companies were not affected and utilized the situation to generate sales for alternative pet foods.
Environmental impact
In a study on the impacts of the pet food industry on world fish and seafood supplies, researchers estimate that 2.48 million metric tonnes of fish are used by the cat food industry each year. It was suggested that there needs to be "a more objective and pragmatic approach to the use of a limited and decreasing biological resource, for human benefit." Marine conservation activist Paul Watson argues that the reduction in forage fish such as those commonly used in cat food (sardines, herring, anchovy etc.) negatively affects fish higher up the food chain like cod, tuna and swordfish, not to mention marine mammals and birds.
Based on 2004 numbers, cats in the US consume the caloric equivalent of what 192,000 (0.0655187%) Americans consume. While pet food is made predominantly using byproducts from human food productions, the increase in popularity of human-grade and byproduct-free pet food means there is increasing pressure on the overall meat supply.
Protein
AAFCO recommends 26% crude protein for feline diets on a dry matter basis, however dry cat food from the top 3 cat food brands in Canada of 2010 contained 34%, 40%, and 36% protein respectively, on a dry matter basis. High animal protein in cat food has increased in popularity due to consumer demand for natural diets, in which protein content is usually much higher than the AAFCO minimum levels. The effects of these trends results in a higher need for animal protein, which may have detrimental effects on sustainability.
6.4% of the USA's greenhouse gas emission is estimated to come from agriculture, and over 50% of the agricultural greenhouse gas emission comes from livestock. The large amount of livestock and fish protein used in pet food diets has been shown to have a much larger impact on the environment when compared to vegetable protein. Following only human trends, by 2050 approximately 1 billion hectares of land will need to be used for agriculture to sustain the human population.
In 2015, an estimated 77.8 million dogs and 85.6 millions cats were living in the USA. The consumer desire to feed their pets premium foods which advertise healthy and human-grade ingredients coupled with the increasing prevalence of pet ownership is causing increased pressure on the meat industry which could result in increased land usage for raising livestock to meet the growing demand. In a study conducted by Okin in 2017, he suggests that if a quarter of all animal protein used in the food of american pets was human-grade, it would be equivalent to the energy needs of 5 million Americans. Okin uses an estimate of 33% of an animal's energy needs is derived from animal products, however this is conservative in that many diets now have more than 33% of their diet in animal protein alone. Lowering protein levels in feline diets may help to improve the sustainability of both the human and pet food system by decreasing pressure on livestock agriculture and ultimately improving environmental effects.
Nutrient chart
See also
- Cat food brands
- Pet food
- Dental health diets for cats
- Senior cat diet
References
Further Information
- Guide to Choose the Best Cat Food
- Vegetarian Society UK on Vegetarian diet for cats
- Scientifically Reviewed & Rated Cat Foods at GoodGuide.com
- The Cat That Ate Tofu Alternet article on vegan cat food
- Buffington CA (June 2008). "Dry foods and risk of disease in cats". Can. Vet. J. 49 (6): 561-3. PMC 2387258 . PMID 18624064. - disputes the claim that dry food is harmful
- Get The Facts - What's Really In Pet Food from Animal Protection Institute
Source of the article : Wikipedia
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