What if clinical symptoms are observed in animals even if only a low mycotoxin contamination was analysed in the feed?

In this case, the interaction of mycotoxins with other main factors is of importance. An already well known fact is that the impact of mycotoxins in animals depends on several animal–, environmental– and toxin–related factors. Young animals are, in general, more at risk to the effects of mycotoxins. Animals placed in a hostile setting characterised by, for example, high temperatures, poor ventilation, high humidity, crowding, and viral or bacterial challenges or other stressful conditions, are more susceptible to the effects of mycotoxins.

Even small amounts of mycotoxins in the feed can have a detrimental effect on a pig’s immune system. These generally immune–suppressive effects of mycotoxins have been well studied. Susceptibility to infections and diseases along with reduced efficacy of vaccination programmes are practical consequences on pig farms. The following studies show the susceptibility of pigs consuming mycotoxins to different specific diseases.

Pigs fed with a diet containing aflatoxin B1 (70–140µg per kg) showed an enhanced susceptibility to infection with Brachyspira hyodysenteriae (Joens et al., 1981).

In a study with 20 piglets (9.6±2.1kg), it was found that a low oral dose of fumonsin B1 (0.5mg per kg body weight per day for seven days) containing culture material may predispose piglets to the development of lung pneumonia induced by Pasteurella multocida (Halloy et al. 2005).

Stoev et al. (2000) demonstrated susceptibility to natural infectious disease in 18 young pigs exposed to the immunotoxicity of ochratoxin A (1–3mg per kg feed) as six animals in the 3–mg group and two animals in the 1–mg group died with clinical and pathological symptoms of salmonellosis and renal ochratoxicosis. Salmonella choleraesuis was detected in the liver and faeces of animals fed this toxin.

In addition, it was discovered that the ingestion of FB₁ alters the cytokine production and decreases the vaccinal antibody response (Taranu et al., 2005).

Marin et al. (2002) reported that pigs fed low doses of aflatoxins (140 and 280µg per kg) tend to have lower antibody levels for Mycoplasma agalactiae than control pigs.

In another study investigating the effects of deoxynivalenol (1,000µg per kg) and zearalenone (250μg per kg), antibody titres of pseudorabies vaccine were impaired in pigs after six weeks exposure (Cheng et al. 2006).

Taking all this into account, great awareness must be given to the interaction of mycotoxins with other main factors. A correct mycotoxin risk management is a key factor for reaching peak performance in animal husbandry.

Further Reading

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