The immunity opportunity in aquaculture: microbial fractions

 Boosting immunity comes with many benefits, including:

• Protection Against Infections: A strong immune system helps defend against viruses, bacteria, and other pathogens, reducing the risk of illnesses like colds, flu, and more serious infections
• Disease Prevention: Enhanced immunity can lower the risk of chronic diseases such as heart disease, diabetes, and certain cancers
• Faster Recovery: A robust immune system can help you recover more quickly from illnesses and injuries
• Improved Quality of Life: Maintaining good immunity contributes to overall health, improving the welfare status

Immune fatigue 

Whilst additives are beneficial to boosting immunity, it’s important to maintain a balance, to avoid ‘Depression of the immune system' (Immune fatigue), and decreased performance in the fish. Some additives are known to stimulate inflammation and ROS production, so their usage must be controlled with short time application and pulse feeding. 

Negative effects that can occur if usage is not controlled include:

• Oxidative Stress: This occurs when there is an imbalance between the production of free radicals and the body’s ability to counteract their harmful effects. Oxidative stress can damage cells, proteins, and DNA
• Chronic Inflammation: Prolonged activation of the immune response can lead to chronic inflammation, which can cause tissue damage and impair the function of organs
• Immunosuppression: Continuous overstimulation can exhaust the immune system, leading to a weakened ability to respond to new infections

These effects highlight the importance of maintaining a balanced immune response in fish to ensure their health and well-being. 

Future challenges

Health challenges are still a major issue for the aquaculture industry. Even if they are better managed, the same diseases have been present for the last 20 years. The issue of climate change also presents significant future challenges, as changing environmental factors will put the fish under increased stress (see Figure 1).

Microbial Factions

There is a clear need for solutions that can improve immunity without compromising the performance and welfare of the animals. This is where microbial factions come to play. Microbial fractions come from yeast or bacteria. Yeast contains a large percentage of nucleic acids from which free nucleotides can be purified. It is important to supply the readily available nucleotides in the fish diet. They are present in additives such as ROVIMAX®.

This additive is produced from a high selection of yeast strains. It is purified in a controlled process, ensuring the highest nucleotide content on the market.

Nucleotides in aquaculture provide a safe immune modulator with a focus on health – figure 2 demonstrates how the different modes of action of dietary nucleotides provide an efficient immune modulation without the risk of overstimulation.

Bacterial postbiotics

Bacterial postbiotics are inanimate microorganisms that confer a health benefit on the host when administered in inadequate amounts. They may contain intact inanimate microbial cells and/ or microbial cell fragments/structures (such as the cell wall, membranes, exopolysaccharides, cell wall anchored proteins, pilli, etc.), with or without metabolites/end products (such as organic acids, peptides, secreted proteins, enzymes, bacteriocins, etc.).

They work by re-enforcing the gut barrier integrity, modulating the microbiome, preventing pathogen adhesion and internalization and providing anti-inflammatory benefits. Postbiotics such as GutServ® Biotics, improve performance and gut resilience, whilst maximising gastrointestinal functionality.

Immunity in aquaculture

In conclusion, the future challenges in the aquaculture industry will still call to modulate animals’ immune status, demonstrating the need for a controlled immune modulation. Specifically selected microbial fractions provide a sustainable solution.

This article originally appeared in International Aquafeed magazine.