Fish meal, or fishmeal, is a commercial product made from fish and the bones and offal from processed fish. It is a brown powder or cake obtained by drying the fish or fish trimmings, often after cooking, and then grinding it. If it is a fatty fish it is also pressed to extract most of the fish oil. Fishmeal is a nutrient-rich and high-protein supplement feed ingredient that stores well, and is used primarily in diets for domestic animals and sometimes as a high-quality organic fertilizer.
Fishmeal can be made from almost any type of seafood, but is generally manufactured from wild-caught, small marine fish that contain a high percentage of bones and oil, and is usually deemed not suitable for direct human consumption. The fish caught for fishmeal purposes solely are termed "industrial". Other sources of fishmeal are from bycatch of other fisheries and byproducts of trimmings made during processing (fish waste or offal) of various seafood products destined for direct human consumption. Virtually any fish or shellfish in the sea can be used to make fishmeal, although a few rare unexploited species may produce a poisonous meal.
Any complete diet must contain some protein, but the nutritional value of the protein relates directly to its amino acid composition and digestibility. The amino acid profile of fishmeal makes this feed ingredient attractive as a protein supplement. High-quality fishmeal normally contains between 60% and 72% crude protein by weight. Typical diets for fish may contain from 32% to 45% total protein by weight. Fishmeal is sought after as an ingredient in aquaculture diets because it contains compounds that make the feed more palatable. This allows the feed to be ingested rapidly, and will reduce nutrient leaching. Nonessential glutamic acid is an amino acid thought to imparts palatability to fishmeal. Fish lipids are also highly digestible by all species of animals and are excellent sources of the essential polyunsaturated fatty acids (PUFA), including both omega-3 and omega-6 fatty acids. The predominant omega-3 fatty acids in fishmeal and fish oil are linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid. Essential fatty acids are necessary for normal larval development, fish growth, and reproduction. They are important in normal development of the skin, nervous system, brain, and visual acuity. PUFAs appear to assist the immune system in defense of disease agents and reduce the stress response. Fishmeal also contains valuable phospholipids, fat-soluble vitamins, and steroid hormones. High digestibility of fish lipids means they can provide considerable usable energy. If a diet does not provide enough energy, the fish or shrimp will have to break down valuable protein for energy, which is expensive and can increase production of toxic ammonia. Fishmeal is considered to be a moderately rich source of vitamins of the B-complex, especially cyanocobalamine (B12), niacin, choline, pantothenic acid, and riboflavin. Benefits
Fishmeal in diets increases feed efficiency and growth through better feed palatability, and enhances nutrient uptake, digestion, and absorption. The balanced amino acid composition of fishmeal complements and provides synergistic effects with other animal and vegetable proteins in the diet to promote fast growth and reduce feeding costs. High-quality fishmeal provides a balanced amount of all essential amino acids, phospholipids, and fatty acids required for optimum development, growth, and reproduction, especially of larvae and broodstock. The nutrients in fishmeal also aid in disease resistance by boosting and helping to maintain a healthy functional immune system. It also allows for formulation of nutrient-dense diets, which promote optimal growth. Incorporation of fishmeal into diets of aquatic animals helps to reduce pollution from the wastewater effluent by providing greater nutrient digestibility. The incorporation of high-quality fishmeal into feed imparts a 'natural or wholesome' characteristic to the final product, such as that provided by wild fish.