Harmful Trace Elements for Pigs and the Signs After Poisoning
What are the harmful trace elements for pigs? What are the signs after poisoning?
There are mainly 21 mineral elements essential for animals. Those accounting for more than 0.01% of body weight are macroelements, including 7 kinds such as calcium, phosphorus, sodium, potassium, magnesium, sulfur and chlorine; those accounting for less than 0.01% of body weight are trace elements, of which there are about 70 or more. In 1973, the WHO announced 14 kinds as essential trace elements: iron, zinc, copper, manganese, iodine, selenium, cobalt, molybdenum, chromium, nickel, vanadium, fluorine, silicon and tin.
Essential trace elements are present in extremely small amounts in the body, but their biological effects are powerful. They participate in the metabolic processes of enzymes, hormones, vitamins and nucleic acids. When deficient, they cause serious nutritional and metabolic diseases, while once excessive, they produce toxic reactions.
For example: the pig body contains 20-25 micrograms of selenium per kilogram of body weight. Depending on the size of the pig, 0.1-0.3 mg of effective selenium needs to be provided per kilogram of daily ration.
When selenium is deficient, it leads to nutritional liver necrosis in affected pigs (manifested as brownish-yellow body fat and subcutaneous edema) and white muscle disease (manifested as pale, swollen muscle fibers, edema, and white stripes on the muscle surface); when selenium is excessive and causes poisoning, it leads to blind staggers in affected livestock (manifested as blindness, abdominal pain, salivation, and muscle paralysis) and chronic alkali disease (manifested as hair loss, cracked hooves, erosion of long bone joints with lameness, cardiac atrophy, liver cirrhosis, and anemia), etc.
In addition to essential trace elements, there are also some harmful trace elements in the pig body that are not required for growth and development, but are present in the diet due to environmental pollution and other reasons and cannot be removed. They can not only accumulate in the pig body and cause damage to the affected pig itself, but can also be transmitted through the food chain and cause harm to the human body.
Common harmful trace elements include lead, cadmium, mercury, arsenic, thallium, antimony, tellurium, etc.
01. Lead (Pb)
The non-radioactive element with the largest atomic weight, a soft and highly ductile weak metal;
After absorption, lead mainly deposits in bone and does not harm the body. Whether poisoning occurs depends on the lead content in the blood and tissues. The symptoms of poisoning are diverse:
(1) Gastrointestinal disorders: such as loss of appetite, constipation, intestinal spasm with lead colic, and gray-blue lead lines on the gums and buccal mucosa formed by the deposition of lead sulfide, etc.
(2) The nervous system is affected, causing lead encephalopathy and convulsions, etc.; peripherally, multiple neuritis may occur, with lead-toxic paralysis.
Lead accumulation poisoningtreatmentThe specific drug is the chelating agent calcium disodium edetate or penicillamine.
02. Cadmium (Cd)
Derived from kadmia, meaning "earth". Discovered in 1817, it coexists with zinc; cadmium and its compounds are all toxic, all soluble in acid, but insoluble in alkali.
Acute poisoning is mostly caused by inhalation, with difficulty breathing, coughing up large amounts of frothy blood-streaked sputum, chills, muscle soreness and unwillingness to stand;
Chronic poisoning causes yellow spots on the neck of the teeth, loss of smell, nasal mucosal ulcers and atrophy, chronic progressive obstructive emphysema, ultimately leading to respiratory failure and renal failure.
Cadmium accumulation poisoningtreatmentThe specific drug is disodium edetate, but due to obvious kidney damage, it is now prohibited, and most are now switched to sodium dimercaptosuccinate.
03. Mercury (Ag)
Commonly known as quicksilver, the only metal that exists as a liquid at normal temperature and pressure, insoluble in acid and alkali, and can evaporate at normal temperature; except for mercury sulfide (cinnabar), mercury vapor and mercury compounds are all chronically highly toxic, and oral administration, inhalation or contact can all cause poisoning reactions.
Organic mercury damages the brain, inorganic mercury damages the kidneys.
Minamata disease is a type of mercury poisoning. Acute poisoning is mostly caused by accidental ingestion of mercuric chloride, corroding the digestive tract; after absorption, it damages the kidneys and causes anuria, and capillary damage causes plasma loss;
Chronic poisoning causes stomatitis and toxic encephalopathy, manifested as listlessness and muscle tremors;
The most dangerous is dimethylmercury, which can be fatal upon skin contact.
Mercury poisoningtreatmentThe specific drug is dimercaprol or sodium dimercaptopropanesulfonate.
04. Arsenic (As)
A metalloid element, existing in nature in the form of sulfide ores (such as realgar As2S2, orpiment As2S3, etc.). The elemental form exists as gray arsenic, black arsenic and yellow arsenic. Elemental arsenic is basically non-toxic, but its oxides and arsenates are highly toxic. Trivalent arsenic (such as arsenic trioxide, commonly known as white arsenic) is about 60 times more toxic than pentavalent arsenic.
Arsenic oxides bind with sulfhydryl-containing enzymes in cells, inhibiting the cellular oxidation process; arsenates are structurally similar to phosphates and can replace phosphate in biochemical reactions, uncoupling the phosphorylation process, interfering with cellular energy metabolism, and affecting DNA synthesis and repair;
In addition, it acts on the vasomotor center, causing capillary paralysis, dilation and increased permeability.
Acute poisoning manifests as acute gastroenteritis and neuritis (manifested as limb numbness or pinprick-like sensation);
Chronic cases show brain asthenia, skin pigmentation or depigmentation, verrucous hyperplasia, and white transverse bands on the nails.
Arsenic poisoningtreatmentThe specific drug is sodium dimercaptopropanesulfonate or sodium dimercaptosuccinate.
05. Thallium (Tl)
Derived from the Greek word "thallos", meaning "green sprout". It is an associated element, known as the perfect poison, and has characteristics such as high toxicity and poor prognosis.
Acute poisoning presents with gastroenteritis symptoms, vomiting, paroxysmal abdominal colic, gastrointestinal bleeding; numbness and soreness of the lower limbs, starting from the soles of the feet and gradually extending to the trunk;
Chronic poisoning presents with neurasthenic symptoms, garlicky breath, numbness of the lower limbs with diarrhea and abdominal pain. Subsequently, hair loss progresses to total baldness, with itching and burning sensation before hair loss; blurred vision; and it is carcinogenic and teratogenic.
For thallium poisoning,treatmentthe drug is Prussian blue, but clinically thetreatmenteffect is poor.
06. Antimony (Sb)
A metalloid with metallic luster, existing in stibnite, used as a cosmetic in ancient times. Antimony and its compounds are all toxic, mainly inhibiting enzyme activity, similar to arsenic; antimony compounds are divided into two categories, trivalent and pentavalent, and antimony compounds in the pentavalent oxidation state are more stable.
Antimony-containing drugs aretreatmentspecific drugs for leishmaniasis, but intake by others from the air can cause poisoning.
Acute antimony poisoning is similar to arsenic poisoning,
Mainly causing cardiac toxicity (myocarditis); small-dose inhalation causes headache, dizziness and depression; large-dose intake, such as long-term skin contact, may cause dermatitis, damage the liver and kidneys, and severe and frequent vomiting.
07. Tellurium (Te)
Derived from tellus, meaning "earth", associated with copper deposits, and belongs to the rare dispersed metalloids. All compounds of tellurium (including oxides, sulfides, halides and telluric acid, etc.) have latent toxicity to humans and livestock. Persistent foul odor of sweat, urine and breath is an obvious characteristic of tellurium poisoning.