Self-preparation method of fish feed
1. Reasonable design of fish feed production formula
Before designing a feed formula for fish, it is necessary to clarify the type and growth stage of the fish to be fed to determine the level of nutrients such as protein and energy in the fish feed. It is necessary to meet the needs of protein for fish growth, and to make the ratio of energy to protein moderate. Both too high and too low energy-to-protein ratios are not conducive to fish growth. When designing the feed formula, the relationship between the nutritional level and bulk density of the feed should also be considered. It is necessary to ensure that the fish can take in sufficient nutrients and make them feel full. Fish mainly use protein as an energy source, and the utilization rate of fat and sugars is low, so the demand for protein is higher than that of livestock feed and poultry feed. Different stages of fish growth have different requirements for various nutrients. For example, the protein content of carp juvenile feed is 41%-43%, fingerling 37%-42%, and large fish 28%-32%.
2. Selection of fish feed making raw materials
The selection of raw materials should be based on the principles of high quality and low price, stable supply and convenient transportation. When conditions permit, the more types of raw materials, the better, so that the necessary amino acids in the feed can be balanced as much as possible, and the needs of fish for various essential amino acids can be met to the greatest extent. Must not use moldy and deteriorating raw materials. Moldy raw materials contain a lot of bacteria and toxins. For example, moldy corn contains highly toxic aflatoxin. These feeds can easily cause fish diseases after being fed. Although raw materials such as cottonseed meal and rapeseed meal are cheap and high in protein content, they contain anti-nutritional factors such as gossypol and glucosinolate respectively. Excessive use will affect the growth of fish, so limit the amount , Generally not more than 10%.
Many fish farmers like to use cheap oil residue and meatloaf, but these raw materials are mixed with a large amount of animal skins, which affects the smooth progress of the crushing and granulation process, and the fish is not easy to digest after eating. The fat contained in oil residues and meatloaf is saturated fat. Fish has a low utilization rate of saturated fat. Excessive intake of rancid fat can also cause fish to suffer from fatty liver and other diseases. Therefore, the amount of such raw materials should be Control it below 5%. In addition, when selecting raw materials, attention should be paid to the moisture content of the raw materials. Excessive moisture will reduce the nutritional value of the feed, and may also cause mildew in the feed and shorten the storage time of the feed.
3. Control of fish feed processing technology
The production process of self-prepared fish feed in rural areas generally includes crushing and mixing. Where conditions permit, it also includes conditioning before pelleting. Crushing can increase the contact area of feed and animal digestive enzymes, improve the digestion and absorption of nitrogen and energy, and reduce the feed coefficient. It is not good to pulverize the particle size to be too coarse or too fine. Generally, the raw materials of the compound feed for fish should be crushed until all of them pass through a 40-mesh sieve, and the content on the 60-mesh sieve is not more than 20%. Mixing is the main link to ensure the quality of compound feed and improve fish feed effect. Feeding practice shows that if the components in the compound feed are mixed unevenly, it will significantly affect the growth of fish, and in severe cases, it will lead to death. This is because the uneven mixing makes the distribution of various nutrients in the same batch of feed uneven, and the effect of the formula cannot be achieved. Certain additives, such as heavy metals, can cause fish poisoning and death if the local concentration is too high.
4. Reasonable use of additives
When producing self-prepared feeds, premixes of vitamins and minerals produced by specialized manufacturers can be used, and reasonably added according to the species and growth stages of the farmed fish. In the self-prepared fish feed production, you can also prepare a small amount of special feed according to your own needs. For example, according to the incidence of fish in your own pond, you can add symptomatic drugs to the feed to make bait for convenient use. When using pharmaceutical additives, you must abide by the relevant national laws and regulations, and it is absolutely not allowed to add drugs that are prohibited by the country. Some farmers add ethanol, which is forbidden in aquatic products, to their feed to speed up the growth of fish. Wow, although ethanol can be anti-bacterial and promote growth, long-term use will reduce the transport resistance of fish, increase the mortality rate during transportation, and also reduce the quality of fish products and endanger human health.
Adding probiotics, enzyme preparations, Chinese herbal medicines and other new additives to feed can significantly improve fish nutrition, promote fish growth, and reduce morbidity. Probiotics are a concept opposite to antibiotics, which refer to active microorganisms or their cultures that can be directly fed to animals and can prevent diseases by adjusting the animal's gastrointestinal microecological balance, promote animal growth and improve feed utilization. Enzymes are proteins with biological activity. As feed additives, they are mainly digestive hydrolytic enzymes. The types include protease, amylase, phytase, cellulase, etc., as well as compound enzyme preparations containing multiple enzymes.
The combination of probiotics and enzyme preparations has a better effect. The optimal combination level in grass carp feed is probiotics 0.52% ~ 0.66%, and enzyme preparations 0.20% ~ 0.21%; the optimal combination level in carp feed is probiotics 0.57%～0.69%, 0.14%～0.18% for enzyme preparation. China is rich in resources of Chinese herbal medicine, and China has accumulated rich experience in the use of Chinese herbal medicine to prevent and treat diseases for a long time. Chinese herbal medicine is added to feed to make bait, which is convenient to use and non-toxic and has no residue. For example, adding "three yellow powder" (the main ingredients are scutellaria, coptis, and cork) can effectively prevent the three diseases of grass carp. The addition of pine needles, wormwood, tuckahoe and other Chinese herbal medicines to fish feed can increase survival rate and promote growth.
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