What foods can help make a cat's coat shiny?
1. Cod liver oil
Cod liver oil is extracted from fish and is rich in omega-3 fatty acids, vitamin A, vitamin E, and vitamin D, all of which are nutrients that can nourish the skin and hair, help beautify the hair, and repair skin and hair cells.
Giving cats cod liver oil can significantly improve their coat health, but be careful with the amount you give them to avoid vitamin A poisoning. 
2. Salmon
Salmon is recognized as a healthy white meat, high in protein and low in fat, and also contains rich omega components. Protein and fat are important nutrients for cats to form their fur.
Feeding your cat salmon regularly will make its fur very smooth, shiny, and soft to the touch.
3. Lecithin
Lecithin is a product extracted from animal and plant materials, and many cat and dog owners are familiar with it. Lecithin has the effect of beautifying a cat's coat and protecting its skin, while the inositol in it also helps to make a cat's fur strong and smooth, and alleviate hair loss symptoms.
For cat owners who want their cats to become more beautiful, consider feeding them some pet lecithin.
4. Cooked egg yolk
Egg yolks are a very nutritious food, containing rich protein, fat, vitamins and minerals. Among them is a special nutrient called lecithin, also known as lutein.
Egg yolks are a natural source of lecithin, and they are rich in nutrients, making them easier to digest and absorb than soy lecithin. So what are you waiting for, cat owners? Feeding your cat two or three cooked egg yolks a week is just about right.