Influencing Factors and Evaluation Methods of Cat Palatability

Factors Affecting Feline Palatability

Feline palatability refers to the phenomenon that when food and feed are eaten by cats, their taste, aroma and texture comprehensively stimulate the senses of cats, making them show likes and dislikes, which reflects the ability of feed to stimulate cats' appetite. The palatability of food reflects the cat's taste, and taste is a central feeling with multiple influencing factors, such as individual differences, food type and environmental changes, etc.

The eating habits of domestic cats can be influenced by feral cats. Small and flexible wild cats like to hunt small prey to feed their hunger, and they often need to hunt multiple times to meet their daily energy needs. Although modern domestic cats do not need to worry about food and clothing, if conditions permit, cats prefer to eat multiple times a day, eat less and eat more, and this behavior will not be affected by age and gender (Mugford, 1977)

1. Influence of sensory factors on cat's dietary preference

1.1 Food smell

Compared with about 9,000 taste buds in humans, cats only have 470 taste buds, which leads to their dull sense of taste, and they can only roughly distinguish the complex tastes of food. This suggests that taste may not play a major role in food selection, with cats or other animals lacking taste buds swallowing food whole to reduce taste perception during ingestion.

Cats have a strong sense of smell, with up to 100 million olfactory cells, which makes cats smell-driven "eaters". The aroma of food mainly depends on the volatile and semi-volatile substances in it, mostly aldehydes, ketones, sulfur-containing compounds and other flavor substances formed by Maillard reaction. In the process of cat food processing, this flavor substance and oil are usually sprayed after granulation to increase the palatability of cat food. The Maillard reaction also occurs during heating of food, which is why cats prefer to eat microwave-heated food.

1.2 Nutrient composition of food

Cats are strict carnivores and require diets derived from animal tissue in order to obtain some essential nutrients that are lacking in foods derived from plants. Studies have shown that the palatability of food is positively correlated with its protein content. Salaun et al. (2017) found in a dietary intake study involving 39 cats that when given a choice, cats would prefer high-protein and low-carb foods. When offered a low-protein, high-carbohydrate diet, the cats restricted their food intake, and the cats did not alter their protein or carbohydrate intake patterns even when an attractant was added to the diet to increase intake. This is because cats are unable to reduce protein oxidation or urea cycle activity if the protein content of the diet is below the cat's minimum requirements, which may lead to irreversible disease (Green et al., 2008).

Red meat, offal, and blood are considered tasty foods, especially liver and kidneys. In a cat preference test for beef and mutton, both beef liver and lamb liver were considered the most delicious foods, while mechanically deboned meat (MDM) was the least popular (Pavinee et al., 2020). Another study found that diets with increased crude fiber and/or mineral content resulted in reduced feed intake in cats (Alegrfa-Morn et al., 2019). Adding fat to food has little effect on its smell, what fat mainly improves is the texture of the food. Cats also appear to have a preference for fat, however oxidation of lipids greatly reduces the palatability of foods (Voragen et al., 1995).

1.3 Food texture and shape

People often focus on the aroma and nutritional value of pet food while ignoring the appearance, temperature, size and texture of the food, and the impact on palatability is also important. During kitten life, cats are influenced by their mother's food choices (Hepper et al., 2012), which include grain texture and form. Cats will prefer moist food with a moisture content similar to meat, and cats may refuse to eat food with sharp edges as this can damage their sensitive digestive lining. The size of the mouth and the shape of the jaw also affect the cat's choice of food, which is more obvious in the palatability of the dog.

2. The impact of environment and individual differences on cats' dietary preferences

The cat's breed, sex, weight, neutering or not, health and mental state will all affect its palatability to food. Studies have shown that neutered cats are willing to eat more food, and the food intake of castrated male cats is greater than that of neutered female cats. A decade-long database of food preference tests for domestic cats shows that body weight affects food preferences, with cats eating less as they gain weight. When animals are satisfied or become satisfied, they show less hedonic and more aversive taste for the same stimulus, suggesting a change in the perceived palatability of food in cats (Ruud et al., 2000).

Early experiences have a potential impact on the formation of long-term behavior, and cats' food preferences are affected by the diet of female cats during pregnancy and lactation, especially in cats aged 4 weeks to 6 months (Zaghini et al., 2005). This supports a class of natural and biologically relevant claims that female cats can pass on proven safe dietary preferences to their offspring. But there are also studies showing that cats' food preferences can change dramatically during the first year of life (Bradshaw, 2006).

Food processing and storage also affect palatability. Except for the processing link in the production process of the product, after the finished pet food enters the pet family, its reprocessing methods include: soaking in water, heating and smashing, and mixing. Soaking in water can soften hard food and change the texture of food, which is beneficial to cats with oral diseases who cannot eat hard food; heating can enhance the volatilization of aroma substances and make cats more appetite; Crushing and mixing some liquid or semi-liquid food can make the cat lick. The structure of the cat's tongue determines that its eating method is to lick food. Domestic cats often display a tendency to choose new foods, which they call "novelty." But this preference did not carry over to all unfamiliar foods, which may be related to the nutritional content of the food (Stasiak et al., 2002).

The alternation of seasons also has a certain impact on the cat's appetite. An analysis of the cat's dietary preference database of the Pet Feeding Behavior Research Center located in the Chilean metropolitan area from 2007 to 2017 found that compared with winter, the food intake in autumn increased. . When the seasons are simply classified as hot (summer and spring) or cold (winter and autumn), cat food intake increases in summer and spring (Alegrfa-Morn et al., 2019). This may be related to the body state of the cat itself, but it may also be related to the fact that higher temperatures can increase the release of volatile substances in food.