What are the nutritional characteristics of pig feed additives?
Feed additives are various trace components added when formulating a diet. Although natural feed contains all kinds of nutrients needed by pigs, such as protein, carbohydrates, fat, minerals and various vitamins, it does not necessarily meet the pigs' needs. When farmers raise pigs in small numbers, the pigs can find the nutrients they need in the soil, and simple mixing of feed is enough; but in intensive pig farms, feed additives must be added when formulating the diet, in order to achieve the full-price nature of the diet, thereby improving its utilization rate and promoting the pigs' health.
According to their function, they are divided into two major categories: nutritional and non-nutritional additives.
(1) Nutritional additives Mainly used to balance or strengthen the nutrition of the diet, including additives such as amino acids, trace elements and vitamins.
1. Amino acid additives: At present, the most widely used are synthetic lysine and methionine, followed by tryptophan, threonine, etc. Their main physiological role is to give play to the production performance potential of pigs and to save protein feed, especially under closed pig house conditions, and they also have the effect of reducing fat deposition in the pig body, improving carcass quality and increasing lean meat rate. In addition, it has also been proven that the use of amino acids can reduce the physiological discomfort in pigs caused by changes in the external environment or other stimulating factors, that is, the stress phenomenon. For example, supplementing the diet with methionine under group feeding conditions reduces mutual fighting among pigs, and tryptophan prevents the tail-biting phenomenon that occurs among piglets after weaning or when stocking density is too high.
It must be pointed out that when formulating a diet, it is first necessary to determine which amino acid in the diet combination is the limiting amino acid, and then select the corresponding amino acid additive. Feeds such as grains, bran and oilseed meal are obviously deficient in lysine, so lysine should be added. If soybean meal is the main source of protein, methionine should be added. As for how much to add, it should be determined according to the content in natural feed and the pigs' requirements.
2. Trace element additives: What is currently on the market is mainly compound trace elements, which mainly contain elements such as iron, copper, manganese, zinc, iodine and selenium. Usually the sulfates, carbonates, chlorides and oxides of these elements are used. The dosages are as follows (amount added per ton of air-dried matter): iron 50~400 grams, copper 5~250 grams, manganese 20~60 grams, zinc 40~140 grams, iodine 1~4 grams, selenium 1~1.5 grams.
Because trace elements are used in very small amounts, it is very difficult to mix them evenly when added directly to feed, and poisoning may even be caused by excessive local content. Therefore, they should be made into a mixture with carriers and diluents, so they are also called trace element premixes.
3. Vitamin additives: These include single and compound preparations. Under intensive pig raising conditions, if compound feed is used and there is a lack of large amounts of green and succulent feed, vitamin deficiency diseases will be caused, so vitamin compound preparations must be used. Imported ones include Ted Vita, and domestic ones include compound vitamin preparations. Add 100~120 grams per ton of feed.
It should be explained that if it is a farmer or a small-scale pig farm, green and succulent feed should be used as much as possible and vitamin additives should be reduced, so that the cost of raising pigs can be lowered.
(2) Non-nutritional additives Mainly include health-care growth-promoting agents, anti-mold agents and antioxidants. Antibiotic preparations as feed additives are used relatively widely in the pig industry and have obvious effects. Health-care agents are mainly sulfonamide drugs, which can prevent the occurrence of diseases under intensive raising conditions. Antioxidants and anti-mold agents are mainly used to prevent feed oxidation and mold spoilage.