Cobalt is an essential component of vitamin B₁₂ or cyanocobalamin. The significance of cobalt as a micronutrient is limited to its potential use in the microbial synthesis of Vitamin B₁₂ in the intestinal tract of shrimp. Sources of cobalt include cottonseed meal, soybean meal, fish meal and yeast. Cobalt may be supplemented as cobalt sulfate and cobalt chloride. Recommended level of cobalt in commercial feeds is 10 ppm (Akiyama et al., 1992).