Fishmeal and fish oil are key components of feeds for fish species (including crustaceans such as shrimp) in aquaculture, as well as pig and poultry feeds. They are also recognised as having particular nutritional advantages in petfoods and increasingly are used in these markets. Fishmeal and fish oil are not just suppliers of crude protein and energy in the diet, although they achieve both in great measure. The presence of numerous important micronutrients such as omega-3 fatty acids (e.g. EPA and DHA), amino acids, particular vitamins such as the B-group and vitamin D, and some key minerals (e.g. Na, K, and Se) are also considered to be important for physiology, growth and health. For some of the major farmed fish species such as salmon, trout, seabass, and turbot, the nutrients present approach the content of the wild diet, and therefore also support the quality of the end product.