Understanding the interactions between nutrition and immune system is crucial for adjusting nutrient allowances in dietary formulations that optimize production efficiency. Among various animal proteins, fish meal (FM) is rich in protein (amino acids), readily available throughout most of the world, and competitively priced against other animal proteins (e.g. milk and blood). In addition, many researchers reported that FM is traditionally recognized as a high digestible protein with a high content of amino acids, vitamins and minerals for pigs. Supplementation of fatty acids by FM and fish oil (FO) is one strategy to modify an animal immune response. As a result of FM and FO effects, those supplementations can result in improved performance and immunity of young animals.