Spirulina is widely distributed in the world's seas and land pale, saline lake, is floating autotrophic prokaryotes, belongs to the cyanophyta oscillatoria orders, oscillatoria families. Algae body due to containing algae blue and green, a microscope filaments spiral. Known all over the world there are 36 species, at present the factory production is mainly on international DunDing nuclear maximum spirulina spirulina 2 freshwater species. Spirulina is the common micro algae, chlorella, green algae, spirulina protein content in the highest, most complete nutrition, digestion, absorption, and the best algae palatability, and safe to eat, has not yet found any toxicity to animals or toxic side effects. A, 1, high protein content spirulina nutrition characteristics of spirulina protein as high as 55%, 70%, and good quality, easy to digest absorb, without any digestion and absorption barrier factor. It is reported that the protein digestion rate at about 75% above, biological value is 79.5% - 87.7%. Beijing institute of aquatic grass carp have been measured and young shrimp absorption rate more than 80% of the protein. Spirulina protein contains 18 kinds of amino acid, various kinds of essential amino acid content is higher, only methionine content is low, but also higher than other plant protein. 2: carbohydrate components special spirulina contains carbohydrate 15%, 25%, 7% 9% mannitol, methyl sugar 7%, alginate 24%, 29%, 5% rhamnose - 6%, uncertain of sugar by 14.4%. Is quite different from that of conventional plant feed composition that, especially in alginate and dew acid are precious aquatic animals must, polysaccharides have the effect of regulation and improve the body immunity, and tumor suppression and anti-radiation effect. 3: rich in vitamin content spirulina how 13 kinds of vitamins, especially rich in carotenoids (is ten times the other plants, carrot is 15 times), is mainly composed of beta beta-carotene and lutein. Are metabolized to animals, astaxanthin and yellow rock mass of Marine products and ornamental fish has A better effect, moreover, beta carrots can be converted into vitamin A in the body, vitamin A can improve immunity, enhance resistance to bacterial and fungal diseases and endurance in low oxygen environment, so as to improve the survival rate of young animals. 4: high proportion of unsaturated fatty acids spirulina fat content is in commonly 5-9%, which is 70-80% unsaturated fatty acid, especially fatty acid gamma linolenic acid, etc must be fairly high, accounting for about 1.1% of the dry weight, gamma linolenic acid is prawns and other essential fatty acids, not only can promote growth, but also can enhance disease resistance. Spirulina contain sterols, mainly is the quality of the cholesteryl and beta sitosterol, not cholesterol, so can strengthen the body immunity, cell senescence, lower cholesterol, and other functions. 5: fiber in cell wall is rarely spirulina algae cell wall is mainly composed of crude protein, lack of fiber, its content is only 4-6%, without any processing by animal digestion, absorption, digestion rate is as high as 70% above, especially for the opening of the prawn bait, the effect is very significant. 6: mineral content is comprehensive, easily absorbed spirulina contains minerals around 50, these minerals in the algae are easy to digest absorb, digest the utilization rate is very high. 7: contain a variety of biological active substances spirulina contains biological active substances present many of nonnutritive add functionality. For example, contain a variety of enzymes, can promote digestion and absorption of nutrients; Containing the growth promoting effect of unknown growth factor and rich in pigment system; Contains improve immune of material of animal immunity and disease resistance and thermal stress factor; To regulate the body metabolism plays an important role in the biological activity of hormone and its antibacterial, antiviral substances, with functions of disease prevention cure. Second, the contribution to the cause of human health spirulina spirulina as the earth's oldest plant, is the most comprehensive nutrition known, one of the most balanced food, by the United Nations food organization known as the "21st century ideal food" 'rank 1: spirulina is rich in the human body can't synthesis of linolenic acid, to help fat metabolism, prevention and treatment of thrombosis, effective against the disease of heart head blood-vessel. 2: spirulina contains active substances, to strengthen the insulin function and low sugar low fat, high protein content, is a person with diabetes ideal nutrition product recovery. 3: spirulina alkaline substances, can neutralize stomach acid, protect the digestive tract ulcer of stomach. 4: spirulina a variety of amino acids and trace elements, can eliminate fatigue, restore and activate the brain cells activity, improve the body immunity. Three, the application of spirulina in the field of aquaculture spirulina can live or algae powder as aquatic animals, in the form of open or seedling bait, or as additives made of granular bait. Algae powder is not easy to sink into the water, not agglutinate, not easily corrupt water quality, for a variety of aquatic animals are all in how to promote growth, strong disease resistance and enhance the survival rate of larvae and improve body color effect. Spirulina in shrimp, soft-shelled turtle, river crab, scallops, abalone, eels and other applications of the experiment proved that spirulina in aquaculture, especially the feeding effect is very significant in the aquatic nursery, has generally promote growth, strengthen the disease resistance, improve the survival rate of the effect, can replace part of conventional feed, reduce the production cost and obtain remarkable economic benefit.