The good, bad and ugly of aqua gut health
By Niels Jeuken
Farmed fish species are generally exposed to a huge variety of microorganisms that inhabit the water column within aquaculture systems. This is especially true for fish farmed in marine settings, as these species must drink large volumes of the surrounding water to maintain an osmotic balance with their environment. Such interactions between environmental microbes and those of the gastrointestinal system of fish can potentially lead to disturbances of the commensal gut microflora, which can consequently affect the normal functioning of a healthy digestive system.
Support the good
An increased level of positive commensal bacteria in the gut can enhance the innate immunity of fish, improve performance and help to support the efficient functioning of the gastrointestinal system.
Figure 1. Illustration of microvilli
Extensive peer-reviewed research has shown that mannan-oligosaccharides (MOS), derived from specific yeast strains, can have a positive impact on the overall gut health of fish. Through feeding these yeast fractions, both the length and density of villi and microvilli can be increased in the gut. This translates to a larger gut surface area and supports enhanced uptake and absorption of nutrients delivered within the feed.
In addition, MOS serve to fortify the epithelial layer of the intestine, thereby enhancing mucus production, which prevents opportunistic bacteria from attaching themselves to the surface of gut enterocytes. As a result, these microbes are readily removed from the fish intestine.
Tackle the bad
Promoting a stronger mucus layer and longer microvilli is a giant leap forward in gut health, but these benefits alone are not sufficient to guarantee optimal functionality within the intestinal tract. Alltech’s Bio-Mos® aids in normalizing gut microflora.
Bacteria attach to the epithelial cells in the gut via fimbriae that recognize certain sugars on the cell exterior. Many pathogenic bacteria attach via specific type 1 fimbriae, which recognize mannose as a surface receptor, depicted in the illustration below.
Figure 2. Illustration of bacterium attaching to Bio-Mos® instead of the gut surface
The Alltech® Gut Health Management program is based on the unique “Seed, Feed and Weed” principle developed by Dr. Steve Collett at the University of Georgia, in which we seed the gut with favorable microflora and then feed the beneficial resident bacteria, maintaining a natural intestinal environment. Through these interconnected processes, we can subsequently weed out potentially unfavorable microorganisms and strengthen the immune defense system of farmed fish.
Avoid the ugly
In modern aquaculture, ensuring optimal gut health is more vital than ever before. We want to avoid ugly situations and produce farmed fish as responsibly as possible, which means the maintenance of optimal water quality parameters is of paramount importance. Every farmer continuously strives to improve the performance of their livestock, and this also applies to terrestrial farms. Fish farmers focus predominately on two key aspects to maintain productivity: the reduction of feed costs and the improvement of growth performance rates.
By implementing our gut health management program in combination with our dedicated on-farm support, we can achieve:
1. Enhanced growth performance, which drives a shorter production cycle.
2. Optimal immune defense, which means reduced treatments and veterinary costs.
3. Strong, robust fish with an optimal fillet quality that satisfies consumer demands.
4. Highly efficient, responsible and sustainable aquaculture practices.
Interested in having our experts help you to achieve optimal gut health in your farmed fish? Email firstname.lastname@example.org today to request an on-farm assessment. Irrespective of your target species and farming environment, we are here to help.