The protein in animal products comes from the protein in feed. The lack of feed materials, especially the lack of protein feed, is the primary factor restricting the development of animal husbandry. The use of amino acids in feed has opened up protein resources other than conventional protein, and opened up a way to solve the contradiction between the development of animal husbandry and the lack of protein feed.
The amino acids produced by the feed additive industry can easily increase the concentration of essential amino acids in the feed, which not only improves the nutritional value of the feed, but also obtains many other beneficial effects. This makes industrial amino acids widely used in the feed industry.
The main varieties of amino acids produced by the feed industry that are most used in industry are lysine, methionine, and a small amount of tryptophan and threonine.
L-Lysine salt is the L-type optical isomer of lysine, the molecular formula is C6H14N2O5·HCI, the relative molecular weight is 182.65; the appearance is white or light brown crystalline powder, tasteless or slightly special odor, easily soluble in water, It is hard to dissolve in ethanol and ether, and has optical activity. The melting point is 263-264°C. my country has formulated the national standard for feed additive L-lysine hydrochloride (GB8245-87).
DL-methionine is also called methionine, its molecular formula is C5H11N02S, the relative molecular mass is 149.22; the appearance is white or light yellow crystals, with a special smell of sulfide; it is easily soluble in water, dilute acid, dilute alkali, and slightly soluble Ethanol, insoluble in ether, melting point 281°C (decomposition). The content of commercial methionine is ≥98.5%. At present, my country has not formulated a national standard for it.
At present, there are four main methods of industrial production: fermentation method; chemical synthesis method; enzyme and chemistry-enzymatic method; protein hydrolysis method. All kinds of livestock and poultry use lysine and methionine, but the use of methionine in poultry feed is emphasized, and the use of lysine is more important for pigs. The rational use of both is more important, and the amount of use varies according to the raw materials and nutrient content of each region.
Reference for the usage of lysine:
Add 0.1-2.5% for broiler chickens, 0.1-0.2% for laying hens, 0.1% in the early stage of laying, and 0.05% in the late stage of laying. It is best to add 3-5% butter, lard, soybean oil and other fats to the broiler feed. In pigs, the amount of methionine used is generally 50% of lysine, and sufficient methionine must be added to the feed for broilers and laying hens. If rapeseed cake or cotton seed cake is used to replace soybean meal, the amount of lysine added must be increased by 20%. If fish meal is used instead of soybean meal, the amount of lysine added can be reduced by 20%. When designing the formula, it should be flexibly controlled according to the different breeds of pigs, different stages and different types of feed ingredients, so as to obtain better feeding benefits.