Expert interview: Monika Leukert on oxidative stress

Monika Leukert is the Product Manager for Antioxidative Solutions and Yeast Derivatives at Lallemand Animal Nutrition

Tell us more about oxidative stress

Oxidative stress is the result of an imbalance between reactive oxygen species (ROS) and the body’s ability to counteract or neutralize their harmful effect with antioxidants. This imbalance can occur due to an overproduction of ROS or a depleted antioxidant system.

Where are these reactive oxygen species (ROS) coming from?

To understand the process, we need to zoom into the body cells. Every living organism relies on energy production and a significant part of it occurs in tiny structures called mitochondria. Depending on the type of cell and its need for energy, there can be hundreds or even thousands of mitochondria per cell. When mitochondria generate energy, they also produce ROS as natural by-products of normal cell activity that also have important roles in the cells. Under normal conditions, our cells have defense mechanisms in place to neutralize these ROS.

If there is an excessive production of ROS and the antioxidant defense inside the mitochondria is overwhelmed, ROS can lead to damages and induce a chain reaction of creating new reactive species (so called free radicals). This is what we call oxidative stress.

What triggers oxidative stress?

There are several factors that can trigger the occurrence of oxidative stress: pollution, sun radiation, dietary toxins, intense physical activity, metabolic disorders, infections, inflammations, vaccinations, medications, aging, thermal stress and many more. For each animal species the triggers can be different.

What are the consequences of oxidative stress for the cells and animals?

When oxidative stress damages mitochondria, it disrupts energy production. Damaged lipids can destabilize cell membranes, affecting their integrity and function. Protein oxidation can lead to misfolding and aggregation, impairing their normal function. DNA damage can result in mutations and genomic instability. Cellular damage can also activate the immune system, leading to chronic inflammation.

Excessive oxidative stress can induce controlled and uncontrolled cell death.

The cumulative effect of all these disturbances leads to a state of cellular chaos, contributing to various diseases and pathological conditions.

What is the role of antioxidants in the cells?

To counteract the damaging effects of free radicals, cells have a network of antioxidants, both enzymatic (for instance superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic (such as vitamins C and E). Enzymatic antioxidants (also called primary antioxidants) can be found in the mitochondria. They are responsible for metabolizing ROS in several steps into water and oxygen. Non-enzymatic antioxidants (also called secondary antioxidants) are free radical scavengers that can be found in the cytoplasm or cell membrane. One molecule of secondary antioxidant can only neutralize one free radical. Together, primary and secondary antioxidants build the antioxidant defense system.

How can we support the antioxidant defense system of animals?

Today, secondary antioxidants are added into almost all animal diets. Vit E, polyphenols, or others are well known for their ability to neutralize free radicals. Also trace minerals (Cu, Zn, Se, Mn and Fe) are supplemented as they are important co-factors of the primary antioxidants. Here it is recommended to select trace minerals in the most bioavailable form, such as organic selenium. A source of highly bioavailable organic selenium is selenium-enriched yeast (ALKOSEL). After absorption a significant proportion of its selenium is used to produce Glutathione peroxidase, an important antioxidant enzyme.

Another possibility is to directly up-regulate the antioxidant defense (primary antioxidants). And here I would like to go back to this French Melon. There is a specific variety of this Melon that is part of the product MELOFEED. It contains a dried melon juice concentrate protected with a specific coating. Studies in different animal species have shown that this product is able to stimulate the production of antioxidant enzymes in the cells and therefore supporting the antioxidant defense system directly in the mitochondria (the first line of defense). This is where secondary antioxidants cannot act, therefore, this can bring an extra layer of protection against oxidative stress.

Any last few words?

There are plenty of causes that can trigger the excessive production of ROS that we simply cannot avoid. But there are also causes that can be limited. Taking actions to reduce the exposure to pollution, toxins, heavy metals, radiation etc. is very important! The consequences of chronic oxidative stress for animals should not be underestimated even if it takes time until they are visible as everything starts in the cells.

An optimal antioxidant strategy with secondary antioxidants, bioavailable trace minerals and a product stimulating the production of primary antioxidants in the body can help to keep the balance in the cells.