NUTRITION ▶▶▶


Mycotoxins and pigs: Does low risk mean no risk?


Acute mycotoxicosis in pigs is a relatively rare phenomenon these days as awareness and technology have increased in recent years. Yet mycotoxins may also be present in low dosages, which can lead to subclinical health problems.


BY DR RADKA BORUTOVA, DVM, PHD, ALLTECH P


Inhibition, DNA, RNA, protein synthesis and DNA damage


(OTA, T-2 toxins, AFB1 and others)


roduced by moulds and frequently occurring in a wide variety of feedstuffs used in pig production, mycotoxins are a dynamic challenge requiring con- sideration and proactive management by pig pro-


ducers across the globe. Over the past four months of using the Alltech 37+ test for mycotoxins in corn, soybean, wheat and barley, 81% of all samples globally contained two or more mycotoxins, with an average of four mycotoxins per sample. When the company’s Risk Equivalent Quantity metric is applied to those results, it shows a higher risk to both nursery and breeding pigs and a moderate risk to grower-finisher pigs. Of all the animal species, pigs are among the most sensitive to the negative impact of unwanted toxins. Considering their high frequency of occurrence along with the concentrations


Figure 1 - The main mycotoxin toxicity mechanisms. Mycotoxins


in which they are found, it is extremely likely that mycotox- ins are routinely consumed by animals. Thanks to continu- ous innovations in mycotoxin management and control, acute mycotoxicosis outbreaks are now considered rare events in modern animal production. However, even low mycotoxin levels – which often go undetected – can be re- sponsible for reduced production efficiency and an in- creased susceptibility to infectious diseases. Additionally, these mycotoxins have been known to interact with other stressors, leading to subclinical losses in performance, in- creases in the incidence of disease and reduced reproduc- tive performance. For animal producers, these subclinical losses are often of greater economic importance than losses from acute effects – but, again, these lower levels are even more difficult to diagnose.


What does “subclinical” mean? This term describes an early stage or mild form of a medical condition, no symptoms of which are detectable. The adverse health effects associated with the contamination of feed ma- terials by mycotoxins may lead to acute intoxications, which can be life-threatening. More common, however, are sub- acute and, often, subclinical alterations of organ function that impair weight gain and reduce productivity. Some of the most significant effects of low mycotoxin concentrations can be observed in the immune and antioxidant systems, where mycotoxin contamination often remains undetected.


Lipid peroxidation,


damage of membrane structure and their function


(most mycotoxins)


Induction of apoptosis (most mycotoxins)


Immunosuppression, hepatoxicity, nephrotoxicity, neurotoxicity, genotoxicity Source: Surai, 2006. 38


Mycotoxin effects on the immune system While impeded growth and reduced productivity are eco- nomically significant, the intrinsic activity of many mycotox- ins in an animal’s immune system is of even more concern. The presence of moderate to low amounts of mycotoxins in daily feed rations increases the susceptibility of animals to vi- ral, bacterial and parasitic diseases. That elevated susceptibili- ty to disease necessitates an increase in therapeutic interven- tions with antibiotics and anti-parasitic drugs. That, in turn, increases the cost of animal health care and the use of an- ti-infective agents – particularly antibiotics – with a conse- quent increase in the risk of induction and the spread of anti- microbial resistance. The immunosuppressive effects of mycotoxins may also result in the incomplete protection of farm animals against viral diseases following vaccination, as their antibody formation is impaired.


▶ PIG PROGRESS | Volume 37, No. 10, 2021


PHOTO: ALLTECH


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