Astaxanthin is a fat?soluble carotenoid with strong antioxidant activity, which has been widely used in the food, cosmetics and health care products industry. As a natural feed additive, astaxanthin has a good ap?plication prospect in animal production, and can improve animal immunity and product quality. This paper aimed to illustrate the physiological functions and mechanism of astaxanthin and reviewed the latest research findings on the application in animal production, which could be regarded as a reference for application of astax...