Royal Canin Hair & Skin 33 cat food for silky, glossy fur and healthy skin; combination of amino acids, vitamin B, zinc, and copper nourish skin and fur. The fur is a mirror for your cat?s health. Shine, thickness, colour ? any kind of change should be watched out for. A deficiency of essential fatty acids (omega-3 & -6) can lead to dull, dry fur and often comes with dandruff. Insufficient supply of certain amino acids may cause hair loss, delayed change of coat, dull, colourless fur or fur discolouration.