When choosing a suitable feed formulation, the existing raw materials should be used to develop proteins, fat, and carbohydrates suitable for freshwater fish. On the basis of satisfying nutritional needs, the sustainable development of freshwater aquaculture can only be promoted by formulating relatively low-cost feeds. In order to develop a good feed, it is necessary to have a comprehensive understanding of the nutrients and raw materials of the feed.
Balanced nutrition in aquaculture production systems is essential for producing healthy, high-quality products. In fish farming (aquaculture), nutrition is critical as feed typically accounts for about 50% of variable production costs. Fish nutrition has improved significantly in recent years with the development of new, balanced commercial diets that promote optimal growth and health. The development of new species-specific dietary formulations supports the expansion of the aquaculture industry to meet the growing demand for fish and seafood products.
Protein: As the main nutrient, fish needs two to three times as much protein as livestock, and this almost determines the price of fish feed. Protein is usually the first consideration when formulating a feed.
Vitamins: Due to the short gut of fish and the limited variety of bacteria, a large amount of vitamins must be added when making fish feed. For example, vitamin C is not needed in livestock and poultry feeds, but it is needed by fish because it can enhance the free immunity and anti-stress ability of fish.
Minerals: Fish absorb various minerals at different rates. It is necessary to add the right amount of trace elements to fish feed, because iron deficiency can lead to anemia, while lack of zinc, manganese, and cobalt can lead to short trunks of fish.
The sources and qualities of feed ingredients used to formulate catfish feed are very diverse, including locally produced and imported ingredients. The main feed raw materials are rice bran (different types), fish meal, meat and bone meal, blood meal, soybean meal, soybean cake, rapeseed meal, cassava, oil, etc. For example, there are many types of fishmeal, including local protein fishmeal, ranging in quality from 35% to 65%, and imported fishmeal. The price of feed ingredients depends on their quality and seasonal fluctuations. To reduce feed costs, fishmeal is usually used in small amounts (less than 10% of the ration, depending on the size of the fish).
There are a number of factors to consider when formulating fish feed. Recipe specifications often vary according to the nutritional requirements of the fish to be fed.
Fish come in different species, life stages, body weights, physiological conditions, and even the quality environment of the pond, which makes them have different nutritional needs.
Importantly, the nutritional requirements of the fish determine the proportions of each type of nutrient used in the production of fish feed. After making the feed formula, the following general production process should be followed:
1) Collect the above raw materials in the required proportions.
Weigh the required amount of various feed ingredients according to the formula specification.
2) Grind the raw material into powder with a feed grinder.
3) Feed the powdery raw material into the fish feed extruder, so that the feed is granular rather than powdery.
4) Cool and dry the finished pellets in the sun, or use a dryer.
5) Store dry pellets in bags until needed and ensure storage conditions keep pellets cool and dry at all times. The pellets can be fed directly to the fish if necessary.