As is the case with other types of livestock farming, antibiotics are widely used in aquaculture to prevent disease. There may soon be a healthier and more eco-friendly alternative though, in the form of seaweed added to existing fish food.
Drawing on previous studies, scientists at Australia’s University of the Sunshine Coast recently experimented with adding 11 different types of powdered seaweed to the pelletized commercial diet of captive mottled rabbitfish (Siganus fuscescens).
Although three varieties of seaweed appeared to be effective in boosting the animals’ immune response, a red seaweed known as Asparagopsis taxiformis proved to perform particularly well. Even when it only made up 3 percent of the fishes’ feed by weight, it reportedly quadrupled their immune response – this means it made them four times more resistant to infection by pathogens.
In fact, the seaweed proved to perform better than four conventional immune-system-boosting products that are currently used in the aquaculture industry.
Interestingly enough, the ingestion of Asparagopsis has also been found to reduce the amount of methane that cows emit in their burps. Going a step further, the Sunshine Coast team believes that a feed supplement made from the seaweed could likewise boost the immune systems of cattle and other farm animals.
“There is no reason that this immunostimulant effect would be limited to just fish,” says the lead scientist, PhD student Valentin Thépot. “It may be applicable to other agricultural industries, and different species of seaweed may offer other immune or production benefits. There is definitely scope for further research.”
The university has patented the supplement, and hopes that it could serve as a financial incentive for the commercial growing and harvesting of Asparagopsis. A paper on the research was recently published in the journal Fish and Shellfish Immunology.