Before designing a reasonable formula for feed formulation, it is necessary to clarify the species and stage of growth of the cultured fish in order to determine the level of nutrients such as protein and energy in the feed. It is necessary to meet the needs of fish for protein growth, but also to make the ratio of energy and protein moderate, high and low energy protein ratio is not conducive to fish growth.
When designing formulas, the relationship between feed nutrients and capacity must also be considered. It is necessary to ensure that the fish can take in enough nutrients and make them feel full. In general, the prices of protein feeds are higher than those of energy feeds. We must not try to increase the proportion of energy feeds and reduce the proportion of protein feeds. This will increase the cost of feeds.
The scientific choice of feed ingredients selection of raw materials should adhere to the principle of quality and cheap, stable supply and convenient transportation. Under the conditions permitting, the more kinds of raw materials, the better, so as to ensure the balance of essential amino acids in the feed as far as possible, and to meet the needs of fish for various essential amino acids. Must not use moldy material, moldy material contains a lot of bacteria and toxins, feeding these feeds can easily cause fish disease. Although raw materials such as cottonseed meal and rapeseed meal are inexpensive, their protein content is also high, but because they contain anti-nutritional factors such as gossypol and glucosinolate, excessive use will affect fish growth. Therefore, to limit the amount, it is generally not more than 10%. Many farmers prefer to use cheap oil dregs and meat powder, but such raw materials contain a large amount of animal skins, affecting the smooth progress of the crushing and granulation process, and the fish are not easily digested after eating. The fats contained in the dregs and meat meal are saturated fats, and some have already begun to rancid because of long storage time. The utilization of saturated fats by fish is low. Excessive intake of rancid fat can also cause fish diseases such as fatty liver. The amount of such raw materials should be controlled below 5%.
The scientific control of the processing technology The process flow of the self-mixed feed generally includes the processes of crushing, mixing, granulating, and the like, and the conditional place includes conditioning before the granulation. The coarse and fine crushed particles are not good. Generally, the raw materials for compound feeds for fish should all pass through a 40-mesh sieve, and the materials above the 60-mesh sieve should not exceed 20%.
The quenching and tempering is a process in which the feed and the steam are stirred and mixed before the feed granulation, and the starch is gelatinized by the conditioning to improve the digestibility. After conditioning, the feed has good fluidity and is conducive to feed formation. The key to quenching and tempering is to control quenched steam and require the use of saturated steam.
The required amount of steam is generally calculated as a percentage of the material 5%. In addition, the tempering temperature should be determined according to the composition of the feed. Because of the high protein content of the fish feed, the feed temperature must be above 85°C. The particle size of the pelleted feed should be determined by the width of the fish's crack, and the particle size of the feed should be less than 1/2 of the slit width.
Reasonable use of additives Feed additives are the generic term for substances added to feeds that promote digestion and absorption of nutrients, regulate body metabolism, ensure animal health, improve nutrient use efficiency, and improve animal production levels, thereby improving the quality of animal products. For vitamins and mineral additives, due to the large variety, low dosage, and high technical content of various vitamins and minerals, the farmers themselves have to buy monomeric micro-organisms and minerals. , can not achieve the balance between nutritional elements. We advise you to use vitamins and mineral premixes that are made by regular manufacturers, and add them according to the species and growth stages of farmed fish.
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