Factors affecting the stability of aquatic feed in water

With the continuous development of the feed industry in the world, the requirements for the indicators of feed pellet are increasingly high, it’s not only the internal quality requirements should be good (such as nutritional performance, disease prevention, industrial environmental protection, etc.), but also the external quality requirements are increasingly high (such as the color, fragrance, size and length ratio of feed pellets, the loss rate in water, etc.). Because of the living environment particularity of aquatic animals, the matchable feed requires good water stability to prevent rapid scatter, dissolution and loss. Therefore, the water stability of aquatic feed is an important index to ensure its quality. Factors affecting the stability of aquatic feed in water are as follows:

First,pellet size of raw materials
The pellet size of raw materials determines the surface area of feed composition. The finer the pellet size, the larger the surface area, the stronger the ability to absorb moisture in steam before granulating, which is conducive to tempering and pellet forming, so that pellet feed has good stability in water, and also can prolong the residence time in aquatic livestock, improve the absorption effect, and reduce water pollution. General fish feed raw materials should pass through 40 target standard sieve after grinding, 60 target standard sieve content ≤20%, and shrimp feed raw materials can pass 60 target standard sieve.

Second, the pellet mill die
The compression ratio of ring mold (effective hole depth /hole size) also has a certain influence on the stability of aquatic feed in water. The feed pellets produced by ring mold pressing with large compression ratio will be higher hardness, tighter structure and longer water resistance time. The normal compression ratio of aquatic ring die is 10-25, and the shrimp feed is 20-35.

Third, quenched and tempered
The purpose of tempering is: 1. By adding steam to soften the material, more plasticity, conducive to extrusion forming, so as to improve the pelleting capacity of the pelleting machine; 2. Through hydrothermal action, starch in feed can be fully gelatinized, protein can be denatured, and starch can be converted into soluble carbohydrates to improve the digestion and utilization rate of bait; 3. Improve the density of pellets, smooth appearance, not easy to be eroded by water, increase the stability in water; 4. The high temperature effect of the tempering process can kill the harmful bacteria such as Escherichia coli and Salmonella in the feed, improve the storage performance and is conducive to the health of aquatic livestock.

Four, adhesive
Adhesives are special additives which plays the role of bonding and forming in aquatic feed, which can be roughly divided into natural substances and chemical synthetic substances. The former can be divided into sugar (starch, wheat, corn meal, etc.) and animal glue (bone glue, skin glue, fish pulp, etc.); Chemical synthetic substances are carboxymethyl cellulose, sodium polyacrylate, etc. In the process of fishery feed production, proper amount of binder is added to improve the stability of feed in water.