Vitamin B12 (cobalamin) is the only water-soluble vitamin in animal feed that contains the metal element cobalt. As a coenzyme, it participates in many key metabolic processes in the body, mainly including promoting the synthesis of proteins and nucleic acids, maintaining the normal function of the nervous system, and assisting folic acid in the hematopoietic process (preventing pernicious anemia). In aquaculture production, it is of vital importance to the normal growth of animals, feed conversion efficiency, reproductive performance and overall health. For monogastric animals (such as pigs and poultry) and fish, since they are unable to synthesize vitamin B12 on their own and plant-based feed contains almost no vitamin B12, they must rely on external supplementation. Although ruminants can synthesize through rumen microorganisms, additional supplementation may also be required at high production loads or during the young age stage. A deficiency of vitamin B12 can lead to a series of problems such as growth arrest, anemia, rough fur, movement disorders, and reproductive disorders (such as decreased litter size and low hatching rate). Therefore, in the complete compound feed of modern intensive breeding, especially for animals that grow rapidly and have high production performance, adding an appropriate amount of vitamin B12 is a necessary measure to ensure their balanced nutrition and production efficiency