The effect of mineral excess on pigs
Minerals are an important nutritional factor necessary for the normal physiological process of pigs, and a lack of them can cause a series of diseases. However, if ingested in excess, it will cause adverse consequences and even death from poisoning.
1. Sodium and chlorine: pigs have poor tolerance to excess sodium chloride, especially under the condition of limited drinking water, and 1% salt in the dry matter of the diet can cause poisoning. The toxic effect of table salt is mainly manifested as severe irritation to the mucous membrane of the digestive tract, and nerve paralysis after absorption. Salt poisoning in pigs is generally caused by overfeeding high-salt feeds, such as sauce residue, salted fish meal, etc., or by suddenly ingesting a large amount of salt due to long-term lack of salt in pigs. Salt poisoning in pigs often occurs in large flocks and has a high mortality rate. The lethal dose of salt in pigs is 100-250 grams, and they usually die within 1-6 days.
2. Calcium and phosphorus: Pigs have strong tolerance to excess calcium and phosphorus, so high calcium and high phosphorus diets generally do not cause poisoning. However, when pigs eat high-calcium and high-phosphorus diets, they can interfere with the metabolism and utilization of other elements, thus causing harm to pig health. Special attention should be paid to the fact that excessive calcium in high-calcium diets can induce zinc deficiency in piglets; excessive phosphorus may interfere with the metabolism and utilization of calcium, cause hyperparathyroidism, and cause a large amount of calcium and phosphorus in bones. Released into the bloodstream, resulting in osteoporosis, prone to fractures and lameness. In general, the dry matter content of the diet should not continue to exceed 1% calcium, and the phosphorus content should not continue to exceed 0.75-0.9%.
3. Iron: Piglets are very sensitive to excess iron. If the supply exceeds the actual need, it will affect feeding and digestion; if the excess is excessive, it may even cause poisoning. Tests have shown that if a piglet ingests 400-500 mg of iron per day, it can cause death due to poisoning.
4. Zinc: Excessive zinc can affect the absorption of iron and copper by pigs, thereby causing anemia. Pigs are relatively tolerant to excess zinc, but if it exceeds 1500-2000 mg/kg of feed dry matter, it will cause poisoning.
5. Selenium: The toxicity of selenium is very strong, and it is necessary to prevent pigs from excessive intake. The toxic dose of selenium to pigs is 5-8 mg/kg of feed dry matter. Selenium poisoning in pigs can be divided into two types: chronic and acute. Chronic poisoning manifests as anorexia, failure, liver fat infiltration, renal degeneration and swelling, cleft hoof and hair loss, etc.; acute poisoning manifests as dyspnea, diarrhea, lethargy, and eventually death due to extreme exhaustion.
6. Iodine: The demand for iodine in pigs is very small. If the supply of iodine is continued, a series of poisoning symptoms may occur, such as salivation, increased nasal fluid and tracheal congestion. To prevent iodine poisoning in pigs, the iodine content in the dry matter of the feed should not exceed 4-5 mg/kg.
7. Copper: Pigs can tolerate a dose of 250 mg/kg of copper in the feed. Acute or chronic copper poisoning can be caused when a large amount of copper accumulates in the liver and other tissues due to excessive copper intake in pigs or due to liver cell damage. Acute poisoning: more than a few hours after eating to 1-2 days after the onset, whichever is shorter. The main symptoms are gastroenteritis, refusal to eat, salivation, vomiting, thirst, abdominal pain, diarrhea, turquoise or blue feces, mixed with mucus and blood, and stench. Muscle slack, unsteady gait, and increased heart rate. Some suffer from loss of consciousness and convulsions; others develop shock symptoms quickly and die within 24 hours. Chronic poisoning: Sick pigs often show depression, difficulty breathing, pale and yellow mucous membranes, hemoglobin in urine, etc., and are often accompanied by symptoms such as jaundice, skin itching and parakeratosis.