Fish Meal - Nutrient Composition

Nutrient Composition

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 is what makes this feed ingredient so 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. Another very important reason why fishmeal is sought after as an ingredient in aquaculture diets is because it contains certain compounds that make the feed more acceptable and agreeable to the taste (palatable). This property allows for the feed to be ingested rapidly, and will reduce nutrient leaching. It is thought the non-essential amino acid glutamic acid is one of the compounds that imparts to fishmeal its palatability.

Fish lipids are also highly digestible by all species of animals and are excellent sources of the essential polyunsaturated fatty acids (PUFA) in both the omega-3 and omega-6 families of fatty acids. The predominant omega-3 fatty acids in fishmeal and fish oil are linolenic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). 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.

Such high digestibility of fish lipids means they can provide lots of 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 cobalamine (B12), niacin, choline, pantothenic acid, and riboflavin.