Economic Impacts Attributed To Aflatoxin

Economic Impacts Attributed to Aflatoxin Dr.Kedar Karki

What is Aflatoxin? • Aflatoxin refers to a group of extremely poisonous mycotoxins produced by two common fungi, Aspergillus flavus and Aspergillus parasiticus. These toxins are named for a fungus that produces them, e.g. “A” from the genus name Aspergillus, “fla” from the species name flavus added to “toxin” to give the name aflatoxin. Mycotoxins are chemical compounds produced by fungi while growing on organic substances such as corn, peanuts, or cottonseed. When these compounds are consumed by animals or humans, they may produce severe undesirable health effects.

What is Aflatoxin? • Although it has been known for over 100 years that moldy grains consumed by animals or humans could cause serious illnesses, it was not until 1961 that scientists proved that the death of over 100,000 turkey poults was caused by consumption of aflatoxin-contaminated grain. Beginning in the 1960's, intensive study of aflatoxin and the illnesses it causes has well documented that serious health effects can occur when aflatoxin-contaminated feed or food are consumed.

Clinical Effects of Aflatoxicosis • Beef Cattle: Early indications of aflatoxin toxicity include reduced feed intake followed by reduced weight gain or weight loss. Often there is reduced feed efficiency, increased susceptibility to stress, and decreased reproductive performance. Chronic aflatoxicosis is characterized by unthriftiness, anorexia, prolapse of the rectum, liver and kidney damage, depression of the immune system, and edema in the abdominal cavity.

Poultry •

Aflatoxin affects all poultry species. Young poultry, especially ducks and turkeys, are very susceptible to aflatoxicosis. Generally, immature, growing poultry should not receive more than 20 ppb aflatoxin in the diet. However, feeding levels lower than 20 ppb may still reduce their resistance to disease, decrease their ability to withstand stress and bruising, and generally make them unthrifty.

Poultry • Laying hens usually can tolerate higher levels of aflatoxin than young birds, but aflatoxin levels still should be less than 100 ppb. Aflatoxicosis can reduce the birds’ ability to tolerate stress and other diseases by inhibiting the natural immune system.

Poultry • Stunted growth, increased mortality, reduced egg size and production, liver and kidney disorders, leg and bone problems, suppression of the immune system with increased susceptibility to infections such as Salmonella are common symptoms of aflatoxicosis in poultry. Decreased blood clotting results in greater downgrading and rejection of birds due to massive bleeding and bruises.

Swine •

Swine are sensitive to aflatoxin, especially nursing or nursery-age swine. Generally, aflatoxin consumption primarily causes liver damage and can result in reductions in feed intake and growth performance. Aflatoxin levels of 100 to 400 ppb cause reduced growth rate and lower feed efficiency. This level of aflatoxin affects breeding stock, unweaned nursery, and growing pigs more than finishing swine (greater than 100 pounds). It is extremely important to keep toxin exposure to breeding swine to a minimum. Aflatoxin levels of 400 to 800 ppb has caused liver damage, bleeding disorders, immune system suppression, abortions, and death.

Sheep and Goats • Sheep and goats are affected by aflatoxin like other ruminants. Aflatoxicosis causes liver damage, kidney damage, anemia, and other symptoms similar to those found in cattle. Early symptoms may include depression, loss of appetite, weakness and slow movement.

Producer Costs • Crops: • • • • • • • • •

Yield loss Restricted markets Nonmarketable product Price discounts Increase product costs Increased post-harvest costs Difficulty obtaining loans on stored grain Disposal of useless crops Monitoring and sampling

Processor Costs • • • • • • • •

Restricted markets Loss of markets Reduced demand Product loss Insurance premiums Litigation costs Monitoring and testing

Livestock and Dairy:

• • • • • • • • • •

Higher mortality rates Reproductive failures (abortions) Reduced feed efficiency Higher feed costs Lower live weight Reduced disease immunity Overall quality loss Lower milk production Unmarketable milk Monitoring and testing

Consumer Costs • Less nutritious food • Higher product prices • Possible health problems •

Social Costs • Regulatory costs • Research and education • Lower foreign exchange earnings • Increased costs of imports.

Handler / Distributor Costs • Extra drying costs • Excess storage capacity • Losses in transit • Loss of markets • Monitoring and testing

Handling Aflatoxin Contaminated Grain • Crop Destruction in the Field: • Crop destruction in the field may be appropriate if aflatoxin levels exceed the maximum allowed for any use or for remedial blending or ammoniation processes. Aflatoxin levels of 1000 ppb or above leave few or no alternatives. Crop insurance may cover crop destruction if a pre-harvest analysis clearly demonstrated the excessive aflatoxin condition

Selective Feeding: •

Adult animals generally are more tolerant of aflatoxin than younger animals. Animal species differ in their sensitivity to aflatoxin consumption.

Screening the Grain: • Various gravity table and shaker screening devices exist which can significantly lower the aflatoxin levels in a lot of grain by effectively removing light weight and broken grain which often contain high levels of aflatoxin. Grain with low to moderate levels of aflatoxin contamination may be cleaned to meet desired use levels. However, in some cases significant amounts of light weight and broken grain may be removed, and thus reduce the total grain volume.

Blending and Ammoniation: • With certain limitations, blending of aflatoxin contaminated corn with aflatoxin-free or less-contaminated corn is an approved practice. The process of ammoniation of aflatoxincontaminated corn or cottonseed to detoxify the aflatoxin.

Feed Additives: •

Several feed additives as anti-caking agents have shown some promise in research tests as aflatoxin-binding agents which inhibit the ability of the aflatoxin to be absorbed in the animal’s gut. Bentonite clay and hydrated sodium calcium aluminosilicate (HSCAS) added to feed have been shown to decrease the effect of aflatoxin fed to swine and poultry. The HSCAS product NovaSil was shown to be effective at 10 pounds of compound per ton of aflatoxincontaminated feed at a minimal cost. The bentonite clay product Volclay has also been shown to be effective when added at the rate of 10 pounds per ton of feed.