Mycotoxin pollution has become a major hazard affecting the development of agriculture, feed industry and aquaculture in the world. How to understand and control mycotoxin has become the primary issue to solve feed safety and livestock product safety, and its importance and urgency should cause us to attach great importance to it. How harmful are mycotoxins?

In recent years, mycotoxin pollution has caused huge economic losses to agricultural and livestock production, and the economic losses caused by fumigatoxin alone to the Asian pig industry may be as high as $1.1 billion per year. According to the Food and Agriculture Organization of the United Nations (FAO), about 25% of the world's crops are contaminated with mycotoxins to varying degrees every year, and about 2% of the crops have lost their feeding value due to serious pollution.

Research from global, national and local provinces and cities shows that mycotoxin contamination in feed is widespread and serious. All kinds of feed raw materials, all kinds of compound feed products, all regions and all seasons have mycotoxin pollution, the detection rate can be as high as 70% to 100%, and the toxin exceeding standard rate determined by feed hygiene standards can reach 20% to 80%. In the contaminated feed, 2 ~ 3 kinds of toxins were detected, and 7 ~ 8 kinds were detected, which showed the characteristics of multiple mycotoxins combined pollution.

1. Molds and mycotoxins

Mold is a general term for filamentous Fungi, and fungi that grow into villy-like, wadding or spider network mycelium on the substrate are called "fungi". Generally refers to Mucor (Mucor), Rhizopus (Rhizopus), Penicillus (Penicillus), Aspergillus (Aspergillus), Chactomium and Fusarium and other fungi. Mold can grow and produce mycotoxins in grains before harvest or during storage, transportation, processing and feeding. Mycotoxins are toxic secondary metabolites produced by mold in the grain or feed it contaminates. At present, there are more than 300 known mycotoxins, of which the relatively serious harm to humans and animals are vomiting toxin (DON), T-2 toxin, Zearalenone (ZEN), fumigatoxin (FUM), ochratoxin A(OTA) and aflatoxin B1(AFB1). The physicochemical properties of several major mycotoxins are almost all characterized by high melting point, poor solubility, high stability and slow decomposition. Jianming industry original works.

2. Influence on feed quality

After the feed raw materials are harvested, they are often contaminated by external mold, and the enzymes they produce can decompose the feed nutrients, making the feeding value decline. Under normal circumstances, the grain is stored whole and the composition is almost unchanged, but after grinding, mold is easy to invade. The harm of mold and its toxins to feed is mainly manifested in:

2.1 Reduce the nutritional value of feed

The growth and reproduction of mold in feed requires the consumption of nutrients in feed, and the decomposition of feed components under the action of microbial enzymes, feed enzymes and other factors, resulting in a serious reduction in the nutritional value of feed. The digestibility of crude protein in the feed after mildew is reduced, and even the nutritional value of the feed is reduced to zero or negative. Kemin industry original works. For example, when winter wheat is infected with gibberellus, the content of fat and starch is reduced, and some molds can significantly reduce the content of vitamin B1, vitamin E, or certain amino acids in infected grains. It is estimated that if the feed has obvious mold, its feeding value will be reduced by at least 10%. The greater the musty taste of feed and the more obvious the discoloration, the more nutritional loss.

2.2 Reduce the palatability of feed

The large number of mold growth and reproduction in the feed will first worsen the perception of the feed, often emitting a special "mildew odor" smell, such as a stimulating smell, sour taste, etc., will produce a thick and dirty feeling, make the taste worse, and will appear abnormal color.

2.3 Affect feed storage, transportation and use

When mold grows, mycelium and substrate interweave into a spider, metabolize to produce heat, water and other metabolic products, so that feed caking, heating and so on. In this way, in the loading and unloading system of large quantities of feed, the feed can not flow well, and the feed in the warehouse will also appear bridge phenomenon, which is difficult to handle. In addition, the use of caked feed is not convenient.

3 Harm to livestock and poultry

Because of the reduced nutritional value of the contaminated feed, different toxins lead to different symptoms of acute and chronic poisoning of livestock and poultry when feeding this feed for a long time. Mold and its toxins harm the health and even life of animals, especially the greatest impact on pigs.

3.1 Reduce production performance and waste feed resources

After feeding feed containing mycotoxin, the most direct manifestations of livestock and poultry are decreased feed intake, diarrhea, slow production rate, reduced egg and milk production, feculence, and low feed utilization rate. Research shows that even if the light pollution, feed utilization can be reduced by 10% to 20%, only one, the current waste of feed in the country at least 10 million tons, worth 30 billion yuan.

3.2 Damage immune function and reduce disease resistance

Another harm of chronic mycotoxin poisoning is to destroy the immune function of animals, reduce the resistance to stress and pathogens, and reduce the protection rate of vaccines. Consumption of mycotoxin can cause thymus dysplasia and atrophy, inhibit the production of complement C4 and lymphocytes, and reduce cytokine secretion. Low dose of fumigatoxin in piglets can reduce the specific immune response to vaccination, and T-2 toxin contamination can reduce the anti-coccidiosis effect of lasallitin on chicks. High doses of mycotoxins can directly cause immunosuppression. Therefore, in the case of mycotoxin contamination, once the animal is invaded by pathogenic microorganisms, it is easy to outbreak disease. In recent years, China's animal epidemic prevention and control situation is grim, all kinds of virulent infectious diseases are repeatedly controlled, not only seriously dangerous animal health, reduce production levels and efficiency, and a large number of antibiotics, increase the safety risks of animal products. There are many reasons leading to animal diseases, and whether the widespread contamination of mycotoxin in feed is related to it is worth studying. Kemin industry original works.

3.3 Damage the body's REDOX homeostasis and reduce the health level

Mycotoxin is an important oxidative stress factor, and a small amount of mycotoxin can lead the body to produce free radicals and destroy the antioxidant ability. The results show that replacing 50% or 100% corn in the basal diet with natural mildew corn can reduce the activities of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), and reduce the antioxidant capacity of rats. Aflatoxin B1 induced the production of thiobarbital reactants (TBARS) and reactive oxygen species (ROS) in primary rat hepatocytes cultured in vitro. The activities of SOD, catalase (CAT) and GPX in liver were significantly decreased by intraperitoneal injection of 2mg/kg aflatoxin B1 in rats. Oxidative stress is also an important factor that destroys the body's immunity. The cellular immunity and humoral immunity of piglets, including the positive protection rate of swine fever vaccine, can be reduced by 30% ~ 40% after the diet containing 2% oxidized fish oil.

4 Impact on animal product safety and human health

Mycotoxins affect the safety of livestock products through direct and indirect effects. The direct effect is that mycotoxin remains in meat, eggs, milk and other animal foods, and the indirect effect is that the disease resistance of animals contaminated by mycotoxin decreases, the amount of antibiotics increases, and the risk of antibiotic residues in animal products is increased.

In order to maintain the sustainable development of feed industry and aquaculture, mycotoxin prevention needs to be strengthened and paid attention to.

*References Kemin Industry, if there is infringement, please contact to delete.