Copper is an indispensable trace element for animals. In recent years, scholars at home and abroad have found that feeding pigs with high-concentration copper fodder has the effect of inhibiting bacterial efficacy and promoting growth, ensuring the health of pigs, accelerating the growth rate of pigs, and increasing feed remuneration. However, high doses of copper (mostly copper sulfate) enter the pigs, causing poisoning, especially in piglets, light diarrhea and slow growth; severe cases of anemia, and finally failure to death. 1 Copper metabolism and physiological efficacy Pure copper is not absorbed because it is insoluble in water. Most of the copper in the feed (mostly copper sulfate) is absorbed in a complex form and only a small portion is absorbed in the ionic state. Pigs mainly absorb copper from the stomach and small intestine, and the cells mainly transport and take up copper through ceruloplasmin and metal ion carriers. Copper is absorbed into blood and combined with plasma protein or copper amino acid, and is widely distributed in cells and liver. Copper is mainly distributed and stored in the liver (about 72%-90% of total body copper), followed by kidney, myocardium, brain, coat and so on. The main route of copper excretion is the digestive tract. About 80% of the copper passes through the liver through the bile and enters the intestines. 90% of the body’s copper is excreted in the feces. Only 2%–4% of the copper is excreted in the urine. For animals, copper is a variety of enzymes (such as superoxide dismutase, ceruloplasmin, metal thiocyanin, cytochrome C oxidase, lysine oxidase, tyrosinase, ascorbate oxidase, galactose The important components of enzymes, etc., are also trace elements necessary for hematopoiesis and prevention of nutritional anemia. Copper not only catalyzes the formation of heme and red blood cells, but also maintains the integrity of cell structure and function. It has positive effects on the hematopoietic and immune functions of animals, the growth and development of nerve cells, bones, connective tissues, and coats. effect. In general, the pig's tolerance to copper is 250mg/kg feed, and if it is greater than 250mg/kg, poisoning may occur, and if it exceeds 500mg/kg, it may be lethal. It is generally desirable to add 125-200 mg/kg to piglets and growing diets. 2 Poisoning mechanism Acute copper poisoning is due to excessive intake of copper salts (mostly soluble copper sulfate) in pigs for a short period of time. Because a large amount of copper salts have coagulation protein and corrosion, coagulation necrosis occurs in the gastrointestinal mucosa. Severe manifestations of hemorrhagic necrotizing gastroenteritis. Chronic copper poisoning is caused by pigs ingesting a small amount of copper for a long time. It is a common form of copper poisoning, but the symptoms of poisoning are acute and are caused by sudden release of copper from the liver into the bloodstream. When copper is poisoned, a large amount of copper accumulates in the liver, and the activity of many important enzymes is inhibited, resulting in hepatic dysfunction and even hepatic necrosis. As a result, the contents of glutamate transaminase, lactate dehydrogenase, plasma arginase, and plasma bilirubin increase. high. When the liver copper accumulates to a certain extent, it releases a large amount of copper into the blood, and the blood copper concentration rapidly increases and enters the red blood cells and is discharged into the urine. The increasing concentration of copper in red blood cells can reduce the concentration of glutathione in red blood cells, increase the fragility of red blood cells and cause intravascular hemolysis. When hemolysis occurs, the copper concentration in the kidney can be high, and the renal tubules are blocked by hemoglobin, causing kidney necrosis, renal failure, hemoglobinuria, and even uremia. At the same time, due to the release of certain factors and hypoxia during hemolysis, plasma creatinine phosphatase concentrations increase and skeletal muscles are damaged. In addition, the concentration of urea and ammonia in the blood increases and ATPase is inhibited, resulting in damage to the central nervous system. Copper poisoning pigs often die from severe hemolysis or uremia. 3 Clinical symptoms When acute poisoning occurred, the pigs showed vomiting and diarrhea. The paste was first excreted in a thin layer and then there was watery diarrhea. The stools were mostly yellow-green or dark green, and the stool was mixed with mucus. In addition, tachycardia, convulsions, paralysis, collapsed to death. In chronic poisoning, the pigs suffered from mental atrophy and decreased appetite. Their body temperatures ranged from 38.9°C to 39.6°C. The hairs were rough, the skin was reddened, the anus was red and swollen, the stool was black and dry like a chestnut, and some stools had a white film-like mucus. With the development of the disease, the conjunctiva is pale, loss of appetite, weakened heartbeat, difficulty in breathing, mouth breathing, lying and sleeping, muscle weakness, unstable gait, little or no urine, red urine, ear, limbs, abdomen, The skin on the buttocks is cyanotic and the body is purple. The late-stage spirit was highly depressed, the appetite was abolished, heart failure, muscle cramps, body temperature dropped below 38°C, and eventually died of coma, convulsions or paralysis. Pregnant sows copper poisoning often miscarriage, mostly mummy and black stillbirth. 4 necropsy Acute copper poisoning usually shows severe gastrointestinal changes, severe gastric mucosal bleeding, ulcers, or even necrosis; duodenum, jejunum, ileum, colon necrosis, and the front part of the duodenum is covered with a dark green film. The large intestine is filled with chestnut-like stools, and the ileocecal valve has a honeycomb-like ulceration at its base. Chronic poisoning manifested as jaundice. The liver was significantly swollen and bleeding. It was orange-yellow, bile was thick, and the gallbladder wall was congested and bleeding; fatty degeneration, brittleness, significant turbidity of myocardial fibers; enlarged kidneys, congestion, and spotty cortex. Bleeding; splenomegaly, purple black; pulmonary edema, thin blood, pale muscle. 5 Treatment measures 5.1 According to the incidence, clinical symptoms, necropsy lesions, combined with feed assay results can be diagnosed as copper poisoning. However, attention should be paid to diseases similar to copper poisoning such as hemolytic diseases, hepatitis, and poisoning caused by hemolytic chemicals. 5.3 The correct use of copper preparations, the amount of copper in feed additives should be adapted to local conditions, and must not be blindly added in large quantities. In addition, the appropriate amount of iron and zinc in the feed, so that the pig's copper, iron, zinc and three elements to maintain a relatively balanced, can prevent copper poisoning. For example, when zinc is 130 mg/kg and iron is 150 mg/kg in the growing pig diet, the toxic effect of 250 mg/kg dietary copper can be prevented, and pig growth and feed consumption can be significantly promoted. 6 Summary With the rapid development of the intensive pig industry, there has been an upward trend in copper poisoning in pigs. There are two main reasons for this: First, misleading producers of feed. Some manufacturers use copper as a secret weapon in feeds. The copper content is several times or even more than ten times that of the national standard. However, it has not been described on the packaging, resulting in poisoning. The second is the blind addition of pig farmers. Some pig farmers lack knowledge in this area and listen to others saying that copper can promote the growth of pigs and they are randomly added to the feed, resulting in poisoning. Turnip,Dried white radish,Dehydrated dried white radish,Delicious dehydrated white radish,Edible dehydrated white radish Jiangsu Tiankang Food Co., Ltd. , https://www.tiankangfood.com
5.2 If piglets are found to have copper poisoning, they should immediately stop feeding copper-containing feeds, feed them to their own mixed feed, and feed fresh green leaves such as Cabbage leaves to give 10% sugar water containing 0.1% of vitamin C for pigs to drink freely. Heavily infected pigs should be isolated and symptomatic treatment, such as 0.2% -0.3% potassium ferrocyanide (yellow salt) solution gastric lavage or internal administration, can also be used magnesium oxide orally, each 10-20g. After taking the above measures for 3 days, the general sick pig's spirit and appetite can gradually recover, but once the hemolysis phenomenon occurs, the prognosis is poor.