We spoke to Gunther Antonissen, who is based at the Faculty of Veterinary Medicine at Ghent University in Belgium after his talk on the impact of mycotoxins on gut health at Biomin’s World Nutrition Forum in Cape Town last month.
He and his colleagues have been weighing up how feed composition might influence the toxic effect of mycotoxins on intestinal health.
“If we look to the impact of mycotoxins, to the performance, we always see that higher levels - for example 10 mg/per kg of feed or 20 mg/per kg of feed) of deoxynivalenol (DON) – has a negative effect on performance, that has been clearly shown, even in small scale studies. But if you go a little bit lower, to more relevant levels of mycotoxin contamination, [under small scale experimental conditions], it is rather hard to see these negative effects on performance parameters.”
However, it was recently observed that even these lower contamination levels of DON and fumonisins (FBs) can negatively affect animal performance when broiler chickens were fed a dysbiosis challenge diet for 39 days under experimental conditions, he said.
The composition of the dysbiosis diet was characterized by decreased digestibility due to an increased level of sunflower scrap and the inclusion of rye and rapeseed scrap, resulting in a high dietary level of indigestible, water-soluble non-starch polysaccharides (NSP), increasing the intestinal viscosity, he explained.
The result, overall, was a decrease of body weight gain of 100g compared to chickens fed a dysbiosis diet without mycotoxins. (Antonissen et al., unpublished data).
The researchers have also been looking at ruminants and solid feed provision, in particular how to tackle Fusarium mycotoxin liver failure in two to three month old beef calves, said Antonissen.
Symptoms, he said, disappeared when replacing the highly contaminated corn and by stimulating ruminal development through roughage administration.
“We have proven that the absorption of DON was much higher when there was no roughage in the diet, when there was almost no ruminal development. If you increase this rumen development, the absorption of the mycotoxin decreased tenfold – going from 50% to 5% - demonstrating that solid feed provision for ruminants is very important in the mycotoxin story.”
However, he stressed that a cow’s rumen contains bacteria that are able to detoxify only a limited amount of mycotoxins, not all mycotoxins.
It is important that industry is aware that mycotoxins, even low to moderate contamination levels in feed, may impair animal intestinal health and immune function and increase animal susceptibility to enteric infectious diseases, he said.
“The effect of mycotoxins is much more than the clinical mycotoxicosis, lesions that we have seen in the past. The ingestion of low to moderate levels of these toxins can cause an array of metabolic, physiologic and immunologic disturbances with the gastrointestinal tract (GIT) one of the major target organs.”