Cyanocobalamine is a large, complex compound consisting of a porphyrin ring containing cobalt. Cyanocobalamine functions as an integral part of the cobarnide enzymes. These enzymes are involved in nucleic acid synthesis, carbohydrate metabolism, lipid metabolism and amino acid metabolism. Deficiency symptoms include poor growth and anorexia. Sources of cyanocobalamine include blood meal, crab meal, fish solubles and fish meal. Recommended supplementation level of cyanocobalamine in commercial feeds is 0.1 mg/kg (Akiyama et al., 1992).