Coated vitamin C is a stable form of vitamin C produced by physically encapsulating L-ascorbic acid (regular VC) as the core material with a coating agent, using the outer membrane to isolate VC from environmental oxygen, moisture, and metal ions, specifically addressing the critical industry challenge that regular VC is highly prone to oxidation, with approximately 80%–98% destroyed during feed pelleting and storage; feed-grade products typically come in active content specifications of 90%, 93%, 96%, 97%, etc. (calculated as L-ascorbic acid), appearing as white to light yellow free-flowing powder, providing sustained release in animals with bioavailability comparable to regular VC; it is widely used in various pelleted feeds, powdered feeds, and premixes, especially excelling in livestock and poultry pellets, aquatic feeds, and anti-stress application scenarios—effectively enhancing animal immune function, reducing stress damage, and improving survival rates and growth performance, with recommended addition levels typically ranging from 100–500 g per ton of feed for fish, shrimp, poultry, pigs, and fur-bearing animals, making it an ideal VC supplement that balances processing stability with biological activity.