Mycotoxins’ impact on swine performance In countries where livestock breeding, namely pigs, play an important role and where the animal potential is stretched to its limits, every factor disturbing the industry and the animal’s efficiency, such as mycotoxins, should be eliminated.

Mycotoxins are naturally occurring secondary metabolites produced by certain moulds/fungi as a result of their organic processes. There are some secondary metabolites of fungal origin medicinal or industrial applications, namely Penicillin. Unfortunately, most mycotoxins are known to hazardously contaminate crops and consequently animal feeds and animal products, causing significant economic losses associated with their impact on animal and human health, animal productivity and domestic and international trade.

Animals vary in their susceptibility to mycotoxins, according to the age and the species of animal and the specific toxin involved (Pier et al, 1980). In general, pigs are considered the most susceptible animals to mycotoxin contamination and amongst them; young animals and female breeders are the most sensitive.

The Producing Fungi

The mycotoxin-producing fungi fall generally into two different groups: those that invade the plants on the field before harvest – the field fungi – and those that occur after harvest – the storage fungi. Avoiding fungi contamination on the field is quite difficult, if not impossible, since by the one side, there is a broad range of factors weakening the plant’s natural defense, thus promoting their growth and mycotoxin formation, namely droughts, floods, poor fertilization, high crop densities, insect or mechanical damage and late harvesting. Avoiding it during storage can be done to some extend with proper storage conditions, controlled temperature and moisture content and good management practices, but in general it is unattainable to totally eliminate the problem. On the other side it is also known that these types of fungi have very few nutritional, environmental and reproductive requirements, thus their ability to survive is well developed.

Hidden Menace

Concerning the detection and analyses of mycotoxins, these are very difficult tasks. For one mycotoxins are invisible, odorless and tasteless and occur heterogeneously in the feed, in the so-called “hot-spots” or nuggets. Additionally, mycotoxins can be bound to certain nutrients as masked-mycotoxins making them undetectable by analytical procedures. Further development in that area of detecting masked mycotoxins is still needed yet unlikely to materialize due to lack of funding and interest. Finally, one can never directly correlate mycotoxin concentration with the effects due to the synergistic effects mycotoxins have in conjunction with each other, meaning that the effects of one mycotoxin might be amplified by the co-occurrence of another. However, based on the knowledge that mycotoxins are very stable to chemical and high temperature treatments (Agag, 2005) that normally kill the fungi spores, it should be clearly understood that in spite of moldy grain having a higher probability of mycotoxin contamination, the apparently sound grains may also be affected by this problem, therefore a farmer may well be feeding these poisonous substances to his animals without even noticing it.

Mycotoxin Challenge

There are many factors that amplify the mycotoxin challenge: 1) Each plant can be infected by more than one fungus; 2) Each fungus is able to produce more than one mycotoxin; 3) Mycotoxins can be produced in many stages of the feed manufacturing, not only before and during harvest but also during storage; 4) Each feed is composed by different commodities; 5) The world trade of feedstuffs has spread mycotoxins amongst commodities worldwide, making it difficult to relate a known location with a specific mycotoxin. Consequently, there is a great probability that many mycotoxins are present in a pig ration, thus increasing the odds of interactions between mycotoxins and the occurrence of synergistic effects, which are of great concern in livestock health and productivity.

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