抗坏血酸
Vitamin C (ascorbic acid) is a water-soluble antioxidant and a free radical scavenger where it will donate an electron to compounds with unpaired elections or reactive but not radical compounds. Supplements of Vitamin C reduce oxidative DNA damage in cats prone to kidney injury, and can be beneficial to add into diets for cats suffering from renal diseases. Vitamin C is not essential for cats and it is not required by the Association of American Feed Control Officials (AAFCO); however, it is commonly added into pet foods as an antioxidant. Ascorbic acid is known to function in gene expression as a co-substrate, and have unique biosynthetic pathways in different organisms.