Dermatological risk factors
From Felipedia
Contents |
Breed predisposition
In contrast to dogs where several skin conditions can be directly related to feline nutrition nutrition, there is little evidence of a link between a breed, nutrient and a specific disease in the feline literature. However, the Siamese seems to have an increased tendency to food allergy dermatitis. Siamese account for 30% of dermatology cases and a genetic predisposition has been proposed[1].
Color of coat
The color of a cat is a complex feature and influenced by genetics, environment (temperature, UV intensity and humidity all alter the coat's color by degrading the pigmentation) and nutrition (many nutrients play a role in pigment production).
The selection of color in pure breed cats has become a specialist's hobby. Pigmentation is linked to the distribution of melanin in the hair shaft (see Colour genetics). Eumelanin (black to brown) and pheomelanin (red to yellow) combine to form the various shades of a cat's coat. The likelihood to produce eumelanin or pheomelanin is genetically determined but the enzyme which catalyzes the conversion from tyrosine can be a limiting factor. Pigment synthesis in the melanocytes depends on the supply of specific amino acids.
- - phenylalanine and tyrosine are melanin precursors
- - cysteine is needed for the production of pheomelanin. It contains a high proportion of sulfur.
A dietary deficiency in tyrosine (or its precursor, phenylalanine) has been shown to induce a reddish change in the black hair of cats. Similarly, the deep orange colored cats turned pale orange when experimentally fed a diet lacking in tyrosine[2].
According to the National Research Council(USA), the adequate intake for an adult cat corresponds to 0.38 g of phenylalanine and tyrosine per kg of metabolic weight (i.e. a level of 15.3 g/kg dry matter). An equal amount of tyrosine is required to maximize black hair color.
Environmental factors
White cats are prone to squamous cell carcinoma, especially on the pinna and nose. Neoplastic changes are often preceded by solar dermatitis (sun burn). Solar radiation is th most ubiquitous mutagen but except indoor confinement, very little can be done to prevent exposure to sunlight and the related free radicals. Research has shown the benefits of antioxidants in preventing UV light induced skin tumors and supplementation of antioxidants in the food may thus be useful[3].
References
- ↑ Carlotti, DN et al (1990) Food allergy in dogs and cats. A review and report of 43 cases. Vet Dermatol 1:55-62
- ↑ Yu, S et al (2001) Effect of low levels of dietary tyrosine on the hair coat color of cats. J Small Anim Pract 42:176-180
- ↑ Liebler, DC & Burr, JA (2000) Effects of UV light and tumor promoters on endogenous vitamin E status in mouse skin. Carcinogenesis 21:221-225
