The nutrients that sustain life, growth and reproduction of animals are mainly proteins, energy, minerals, vitamins and water. Taking pigs as an example, the role of nutrients in feeds is introduced.

1 protein

The protein in the feed is digested and decomposed in the gastrointestinal tract by the gastrointestinal tract, and the amino acid is absorbed by the intestinal wall and enters the blood for use by the pig. When the pig diet lacks protein, it will affect the health, growth and reproductive performance of pigs, reduce productivity and product quality; piglets will suffer from anemia due to decreased hemoglobin, which will reduce disease resistance and slow down growth; Loss of libido, sperm deformity and lack of vitality, affecting breeding and breeding, so that the conception rate and litter size decreased; sows estrus is abnormal, the number of ovulation is reduced, fertilized eggs and embryos die early, stillbirth, abortion and weak postpartum lactation. If the protein in the diet is too much, the liver and kidney of the pig will be overburdened and damaged, and the boar will be infertile.

In pig protein nutrition, lysine and methionine are often insufficient, and the faster the pig grows and the higher the growth intensity, the more lysine is needed.

2 energy

The pigs need energy to sustain life, grow, develop, multiply and perform various physiological activities. The energy needed for pigs comes from the carbohydrates, fats and proteins in the feed. These three substances oxidize in pigs to release energy for maintaining body temperature, physiological activity and production activities. Each gram of carbohydrate produces 17.36 MJ of heat, 39.08 MJ of fat, and 23.285 MJ of protein. However, in view of the special important role of protein in the body, it is generally not used as an energy substance in pig feed.

The energy source of pigs is mainly carbohydrates. During the growth of pigs, when the energy feed is excessive, the pig body converts too much carbohydrate into fat and stores it in the body; on the contrary, if the energy feed is insufficient, the fat and even body protein stored in the pig are used. As an energy supply to maintain its normal growth and development.

Carbohydrates include starch, sugar and cellulosic materials. The first two are easy to digest and absorb, and the heat production is high. The crude fiber contains a small amount of lignin in addition to cellulose. The ability of pigs to digest crude fiber is extremely weak. If the crude fiber content in the diet exceeds 15%, the feed intake of pigs will be greatly reduced due to poor palatability.

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3 minerals

Minerals have exact physiological functions and metabolism in animals, and inadequate or lack of dietary supply can lead to deficiency and biochemical changes. Replenishing the corresponding mineral elements, the mineral elements that can disappear after lack of disease are called essential mineral elements, which can be divided into macro mineral elements and trace mineral elements according to different body contents. If there is a lack of minerals in the pigs, the growth will stop, and in the case of mineral deficiency, severe cases can cause death.

3.1 Constant mineral elements

The major mineral elements are calcium, phosphorus, sodium, potassium, chlorine, magnesium, sulfur, and the like.

1 Calcium, phosphorus calcium, phosphorus are the main components of bones and teeth, which together account for 75% of the mineral content of pigs. Lack of calcium, phosphorus, or improper proportion of calcium and phosphorus in the diet, the pig will have a variety of calcium and phosphorus deficiency.

2 Magnesium and magnesium participate in the composition of bones and teeth, as an activator of enzymes or directly involved in enzyme composition, participate in the synthesis of genetic material DNA, RNA and protein, regulate neuromuscular excitability, and ensure the normal function of neuromuscular. Pigs need less magnesium, and daily feed can meet their needs. When the magnesium content of the piglet diet is less than 125ppm, there may be a deficiency, resulting in growth retardation, excessive excitement, paralysis, anorexia, muscle twitching, and even coma. However, excessive magnesium in pig diets also causes animal poisoning, mainly manifested by lethargy, movement disorders, diarrhea, decreased feed intake, reduced productivity, and even death.

3 Sodium, chlorine, potassium sodium, chlorine and potassium are widely present in various tissues and milk of pigs, which play an important role in maintaining the body's osmotic pressure, regulating acid-base balance and controlling water metabolism. The lack of sodium in the diet will reduce the utilization of nutrients in pigs, and it can affect the reproductive performance of sows. It may also be a factor that causes mutual biting or other similar disability. The lack of potassium in the diet, the appetite of pigs is obvious. Deterioration; lack of chlorine in the diet causes the growth of pigs to be blocked.

4 Sulfur animals contain about 0.15% sulfur, a small amount in the form of sulfate in the blood, most of which exists in the form of organic sulfur in muscle tissue and bone teeth. The sulphur deficiency in pigs is characterized by weight loss, and the growth of horns, hooves, claws, hairs and feathers is slow.

3.2 Trace mineral elements

This type of mineral is rarely required, and its content in pigs is only less than one part per million of body weight, so it is called trace elements. Common trace elements are iron, copper, zinc, manganese, iodine, selenium and the like.

1 In iron pigs, 65% of iron is present in the blood. It is closely related to the transport of oxygen in the blood and the biooxidation process in the cells. Once iron deficiency occurs, it is prone to nutritional anemia.

2 Copper copper is not a component of heme, but it plays a catalytic role in the formation of fibrin and red blood cells. In addition to hematopoiesis, copper is also involved in the development of bone marrow and the normal metabolism of the central nervous system. It is also a component and activator of various enzymes in the muscle.

3 zinc deficiency in zinc pigs will reduce skin resistance, skin keratosis, scarring, hair loss, loss of appetite, decreased daily weight gain, decreased feed utilization, etc., sows have reduced litter size and piglet weight loss The amount of lactation is reduced.

4 Manganese manganese is a component of several important biocatalysts and is closely related to hormones. It has effects on estrus, ovulation, embryo, breast and bone development, lactation and growth. Manganese deficiency in pigs can cause bone deformation, slow growth, and decline in sexual function.

1 Iodine iodine is the main component of the synthesis of thyroxine. If the porcine sows are deficient in iodine, the piglets are large, hairless or hairless, thick and mucous edema. Most piglets are still alive at birth and even weigh more than healthy pigs, but they are weak. Often died within a few days after birth, and the survival rate is low.

6 Selenium Selenium is one of the essential elements for pig life activities. According to the survey, selenium deficiency is often found in soil and feed in many parts of Northeast China, Northwest China and Shandong. Feeding pigs with selenium-deficient feed is prone to selenium deficiency.

The effect of selenium on breeding pigs is similar to that of vitamin E. Supplementation can reduce the vitamin requirements of pigs and reduce the loss of vitamin E deficiency. Selenium is closely related to the positive metabolism of vitamins. When pigs lack both vitamin E and selenium, selenium deficiency will manifest itself quickly; selenium is insufficient, but vitamin E is sufficient, and selenium deficiency in pigs is not easy to manifest.

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4 vitamins

Currently determined vitamins can be classified into two categories: fat-soluble and water-soluble according to solubility.

4.1 Fat soluble vitamins

It refers to vitamins A, D, E, and K. They are mainly composed of mountain carbon, hydrogen, and oxygen.

1 Vitamin A can protect the health of the mucosal epithelium, maintain normal reproductive function, promote growth and development, and maintain the health of the respiratory system and the optic nerve system. In the absence of pigs, the appetite of the pigs is reduced, and night blindness occurs; the piglets stop growing, the eyelids are swollen, the fur is dry, and they are prone to pneumonia; the sows are not estrus or estrus, and are prone to miscarriage, birth and death, and no eyeball piglets; boars are not sexually active. Strong, poor semen quality.

2 Vitamin D can lower the intestinal pH value, thereby promoting the absorption of calcium and phosphorus, and ensuring the normal development of bones. The content of calcium and phosphorus in the feed is sufficient, and the ratio is also suitable. However, if the vitamin D content is insufficient, it will also affect the absorption and utilization of calcium and phosphorus. In the absence of it, it affects the absorption of calcium and phosphorus, and produces calcium and phosphorus deficiency.

3 Vitamin E can maintain the normal reproductive function of pigs and has antioxidant effects. In the absence of boar, the ejaculation volume is reduced, sperm motility is reduced, testicular atrophy is degraded in severe cases, and sperm is not produced; sows have a reduced fertility rate, post-fetal embryo development is easily absorbed or midway abortion or stillbirth; white pigs develop white muscle Ill, suddenly died suddenly.

4 Vitamin K Vitamin K is related to blood coagulation. Lack of clotting time, hematuria and respiratory abnormalities, systemic subcutaneous hemorrhage in piglets.

4.2 Water-soluble vitamins

Refers to B vitamins and vitamin C.

1 vitamin B1 deficiency, loss of appetite, gastrointestinal disorders, myocardial atrophy or necrosis, neurogenesis inflammation, pain, paralysis and so on.

2 Vitamin B2 improves feed utilization. Lack of production leads to poor appetite in pigs. Growth stops, the fur is rough, sometimes there are dandruff, ulcers and fat spills, and the secretions in the eyes are increased. The sows are shortened during pregnancy, early embryos die, lactation declines; boars testicular atrophy. Sometimes all piglets born are dead or die 48 hours after birth. When the pig house is cold, the vitamin B2 requirement of the pig will increase.

3 Pantothenic acid When pigs lack pantothenic acid, they often suffer from skin dermatitis, loss of appetite or disappearance, diarrhea, paralysis of hind limb muscles, and ulcerative lesions of the lips and tongue. Anemia, ulcerative lesions in the large intestine, heart and liver and weight loss, vomiting,

4 Vitamin C participates in the oxidation and reduction process, and is important for the synthesis of collagen gelatin, intercellular binder, neurotransmitters (such as norepinephrine), steroid hydroxylation, amino acid metabolism, antibody and erythrocyte production. Role to prevent scurvy.

5 water

Lack of water or insufficient drinking water is extremely harmful. When the body's water is reduced by 8%, it will cause severe thirst, loss of appetite, and slow digestion. When it is reduced to 10%, it will cause serious metabolic disorder, and a 20% reduction will lead to death. Pigs can obtain water from the following three aspects: one is the metabolic water produced by the decomposition of carbohydrates, fats and proteins; the other is the water contained in the feed itself; the third is drinking water. Among them, drinking water accounts for the vast majority of water intake.