When choosing comprehensive feed formula, we should starts from the existing raw materials, develop new protein source, fat, carbohydrate, which is suitable for freshwater fishes. On the basis of meeting the nutritional requirements, a comprehensive and relatively low cost of feed should be prepared, which can promote the development of freshwater aquaculture, to develop a good feed, it is necessary to have a comprehensive understanding of the nutritional composition of the feed.
I. 3 Necessary Elements in Fish Feed Formulation
Protein: Protein is generally the first consideration in the formulation of nutritional element, fish needs twice or three times amount of protein than livestock as a source of energy, which also almost decides the price of fish feed.
Vitamin: Fish has short intestinal, and the type and quantity of bacteria is rare, which means lots of vitamin need to be provided when producing fish feed. For instance, vitamin C doesn't need to be add in livestock and poultry feed, but in fish feed do need because it can improve free immunity and anti stress ability of fish.
Minerals: Fish has different absorption rate for various minerals. It is necessary to add right amount of trace elements in the fish feed, because Fe deficiency can lead to anemia, while Zn, Mn, Co will cause short trunk.
II. Formula of Compound Additives
A. Formula of compound additives for omnivorous fishes
Omnivorous fish compound additive is according to the omnivorous fish biology design features, generally divided into two kinds: mineral additives and vitamin additives.
B. Formula of compound additives for carnivorous fishes
C. Formulation of compound additive for herbivorous fishes
III. Scientific Feeding Method
Feed is one of the biggest cost of fish farming, pay attention to scientific feeding method, it is not only conducive to the healthy growth of the fish, but also can save the feed, and effectively improve the benefit of fish culture.
A. Fish feed pellet: The diameter of pellet feed is usually 2.5 mm -8 mm, length is 5 mm ~10 mm. The fish feed pellet sizes differ when manufacture change the die of fish feed extruder. B. Oil-cake feed stuff: for fingerlings, oil-cake should be cracked, soaked, and ground into thick liquid, for adult fish, soaking and being soft is OK.
C. Grain feed: large particles of grain like corn should be crushed by crusher first, small particles of grain like paddy should use its buds, the tender bud has a high nutritional value, for fish it is easy to digest, absorb, and grow.
D. Plant feed: plant, after removing the soil, are generally used to feed medium and adult fish. For fingerlings, plant feed should be crushed and ground into thick liquid, mixed with 0.2% of salt then splash into the water.
E. Bran feed: for fingerlings, bran should be soaked and ground into thick liquid; for adult fish, should be used when it fermented to a wine aroma.
F. Protein feed: earthworms, maggots, and insects are high-quality animal protein feed for fish, can feed fish without processing.
G. Feces feed: Chicken manure, pig manure and cow dung are quality fish feed. Dried this manure and ground into powder, then mixed with other feed in accordance with a certain proportion. The common proportion is 40%-50% for chicken manure, 50%-70% for cow dung, 30%-50% for pig manure.