Proteins are composed of amino acids, which are important building blocks of muscle, skin, hair, skeleton, and other tissues in the body. Along with a higher protein requirement, kittens also have a higher requirement for a number of essential amino acids compared with adult cats. Studies have shown that a deficiency in essential amino acids caused kittens to lose weight2, which of course, is unfavourable during growth. This is because essential amino acids cannot be synthesised by the animal and therefore must be present in the diet. Conversely, it has also been shown that excessive arginine, methionine and tryptophan levels can lead to a decrease in growth rate and food intake3,4. Therefore, these nutrients have maximum nutritional levels (arginine 3.5g/100g DM, methionine 1.4g/100g DM, tryptophan 1.7g/100g DM)¹ to support growth.

Kittens (and adult cats) cannot synthesise taurine from other amino acids and so it must be provided in the diet to ensure healthy growth and normal neuronal and visual development.

Essential Fatty Acids for Essential Development

Dietary fats deliver the most concentrated energy source in a balanced diet for kittens, helping to meet their increased energy demands during rapid growth effectively. As well as providing energy, sources of fat within the diet also supply essential fatty acids (EFAs). The essential nature of fatty acid is primarily due to the inability of an animal to synthesize sufficient quantities in the body to meet its needs, which is why they must be present in the diet. However, EFAs also possess important functional and structural characteristics that play a vital role in supporting healthy development and function of the body, which also contribute to their essential nature.⁵

For kittens/cats, as for other mammals, the essential fatty acids belong to the omega-3 and omega-6 families.

In the absence of dietary LA and AA, signs of deficiency in kittens include lethargy, retarded growth, rough, dry coats with dandruff and skin lesions ⁷. Supplementation of an EFA deficient diet with safflower seed oil (as a source of LA) was able to prevent the development of poor skin and coat condition and loss of water through the skin, with the negligible conversion of LA to AA demonstrating specific functions of LA as an EFA independent of AA ⁸.

Further studies in cats fed diets containing adequate LA but deficient in AA showed reproductive failure and impaired platelet aggregation, which could be treated by the addition of AA ⁹, ¹⁰. An important point to note is that the impact of nutrition on the development and health of a kitten begins before birth, and the importance of providing adequate levels of EFAs, especially AA, in the diet of the mother during gestation and lactation is highlighted. During reproduction and growth, a minimum level of 20 mg/100g DM is recommended which is significantly higher than the recommended level for adult cats (6 mg/100g DM)¹.

These studies indicate that LA is essential for functions such as growth, lipid transport, normal skin and coat condition and maintenance of the epidermal permeability barrier, while AA is required for functions that depend on eicosanoid formation, such as reproduction and platelet aggregation ¹¹.

EPA is a precursor of DHA and can also be incorporated into cell membranes, from where it can be released and converted to eicosanoids, which play an important role in immune and inflammatory reactions. Importantly, the eicosanoids derived from EPA are different to those produced from AA and associated more with anti-inflammatory properties in contrast to the inflammatory properties of AA-derived eicosanoids¹².

Kittens need more calcium and phosphorus than adult cats to support the growth and development of their bones and teeth. It’s recommended that kittens require a minimum of 1g/100g DM of Ca in their diet and 0.84g/100g DM of P, compared to adult cats that only need 0.4g/100g DM of Ca and 0.26g/100g DM of P once fully grown. Not only is the level of these minerals in the diet important, but also the ratio in which they are supplied. For kittens, it’s advised that this should be no higher than 1.5:1 (Ca:P) but can be increased to 2:1 in diets for adult cats ¹.

Vitamin D is also an essential nutrient for cats as it works to ensure that the body absorbs sufficient levels of calcium and phosphorus. Kittens must receive a minimum of 28IU/100g DM in their diet, which is slightly more than the minimum requirement of adults at 25IU/100g DM ¹. A deficiency in vitamin D or low levels of Ca and P can lead to fractures due to decreased mineralisation of bone and bone deformities (e.g. rickets), leading to painful long-term conditions.