When mycotoxins contaminate feed: What is oxidative stress?

August 22, 2018

When mycotoxins contaminate animal feed, the effects on livestock can be serious. Some mycotoxins, like aflatoxin, are carcinogenic. Others can impact the immune system or the blood, damage organs, cause miscarriages and provoke severe vomiting, among many other effects.

Some of these effects are linked to oxidative stress, which happens when unstable atoms damage living cells. Here, we’ll break down what that means for animals and farmers/producers.

Oxidative stress in the body

Oxidative stress boils down to imbalances in the body between two things: free radicals and antioxidants. Free radicals are oxygen-containing molecules with an uneven number of electrons. Antioxidants are chemical compounds that inhibit oxidation by essentially donating electrons to free radicals, making them stable. In a sense, antioxidants protect bodies from the effects of free radicals. If there’s an imbalance, free radicals are, well, free to damage the body.

With the imbalance, free radicals can more easily cause chemical reactions (called oxidation) in the body by reacting with other molecules. To a degree, oxidation is normal and free radicals help fight pathogens, but an imbalance leads to the same free radicals beginning to cause damage to fatty tissue, DNA and proteins in the body — which is oxidative stress.

Mycotoxins like deoxynivalenol (DON) have been shown to lower the total antioxidant capacity and increase the level of free radicals in intestinal cells. One recent study showed that a mixture of mycotoxins — including aflatoxin, DON and fumonisin — resulted in a 22% increase of oxidative stress damage to proteins in nursery pigs.

What does this mean for livestock?

It’s safe to say, in general, that less healthy livestock are less productive. Oxidative stress can make animals less healthy in several ways, including reduced gut function and an altered immune system. This amounts to lowered performance and productivity. For instance, the nursery pigs mentioned above, after consuming a mycotoxin mixture, had their average daily weight gain reduced by about 14% — in part due to oxidative stress, and in part due to the other detrimental effects of mycotoxins.

In dairy cows, subclinical mastitis is one of the most prevalent diseases that causes drastic losses in the dairy industry — and it’s also linked to oxidative stress.

A long production cycle makes laying hens ideal candidates for chronic health impacts from mycotoxins in feed. The liver, which is where mycotoxins are metabolized, also happens to play a big role in egg production. It’s been shown before that higher levels of DON in feed leads to more oxidative stress damage in liver tissue — which decreases egg production. It’s also been linked to decreased feed efficiency and increased incidence of fatty liver, which can result in a 25% drop in egg production.

Neogen offers the feed and grain industry the most comprehensive line of mycotoxin testing solutions. See our website for more information.

Category: Agriculture, Milling & Grain, Mycotoxins