Stress reactions to mycotoxins in animals

Many trials have proven the significant negative impact of mycotoxins on performance in pigs and poultry. Looking at the effects of mycotoxins at a cellular level, it is becoming obvious that many stress reactions seen to mycotoxins in animals are those commonly seen in response to other stressors.

One reaction to stressors is an increase in Reactive Oxygen Species (ROS). ROS are produced endogenously by normal metabolic processes, but amounts may be increased markedly by certain stressors, including mycotoxins. Deficiencies of natural protective substances or excess exposure to stimulators of ROS production may result in oxidative stress, which occurs when ROS exceed the capacity of antioxidants. Oxidative stress is a major factor related to the development of inflammatory diseases.

Consumption of DON-contaminated feed in pigs, not only increases oxidative stress, it has also shown to impact the gastrointestinal tract, causing epithelial injuries of the stomach and the intestine, leading to intestinal inflammatory response.

In vitro and in vivo studies have also demonstrated that DON compromises the intestinal barrier function and increases gut permeability. Furthermore, it has been shown that mycotoxins modify the intestinal microbiota in pigs and in poultry. However, not all mycotoxins show this effect. For example, feeding pigs with fumonisin was not reported to induce any modification of the intestinal microbiota, whereas DON did.

In the chicken a high dose of ochratoxin exhibited significant numbers of Salmonella typhimurium in the digestive tract when compared to non-administered birds. However, feeding birds with high levels of aflatoxin or T-2 toxin had no effect on incidence or severity of S. typhimurium colonization.

Taken all together these type of responses at the cellular level will predispose the animal to intestinal and systemic infections and impair efficient digestion and absorption of nutrients, with the associated effect on animal productivity and efficiency.