Aspergillus-derived β-glucan enhances salmon resistance against ulcerative diseases: study finds 

BELGIUM – A groundbreaking study conducted by Onda, in collaboration with Belgian citric acid and mycelium producer Citribel, has revealed that Aspergillus niger mycelium-derived β-glucan, branded as Mycofence®, significantly improves disease resistance in Atlantic salmon. 

The study, led by Fabio Zanuzzo, focused on the effectiveness of Mycofence compared to commercially available yeast-derived β-glucan in combating ulcerative diseases caused by Tenacibaculum maritimum and Moritella viscosa.

Tenacibaculum maritimum, a gram-negative bacterium, is the causative agent of tenacibaculosis, an important bacterial disease that affects a large number of marine fish species, causing heavy losses for the aquaculture industry worldwide. 

On the other hand, winter ulcer is a disease caused by infection from the gram-negative bacterium, Moritella viscosa, commonly reported in farmed Atlantic Salmon.

Researchers propose that M. viscosa disrupts the cytoskeleton which affects cell rigidity and structure, followed by pore formation and lysis caused by secreted products from the bacterium. 

This Belgian research involved feeding Atlantic salmon diets supplemented with varying levels of Mycofence and commercial yeast β-glucan for five weeks. 

Afterwards, the fish were subjected to immersion challenges with the ulcerative bacteria. The findings were compelling—Mycofence outperformed commercial yeast β-glucan in enhancing immune response and reducing mortality.

Key findings included a 42.6% reduction in mortality from T. maritimum and a 31% reduction from M. viscosa when using Mycofence at a 0.3% dietary inclusion rate. 

Importantly, there were no significant differences in weight and growth performance among the diet groups, underscoring Mycofence’s unique advantage in bolstering disease resistance without compromising growth.

“Our research clearly demonstrates that Mycofence significantly improves the immune response and survival rates of Atlantic salmon during ulcerative disease outbreaks. These findings provide a promising alternative to commercial yeast β-glucan and can greatly benefit aquaculture practices,” Zanuzzo stated.

The study highlighted that fish fed with Mycofence exhibited a marked upregulation of the cr3 transcript, a critical marker for immune response and β-glucan recognition. This discovery offers insights into the underlying mechanisms driving enhanced disease resistance.

This research is one of the first publications from Onda under its new identity, following its separation from its U.S.-based counterpart, The Center for Aquaculture Technologies. 

With these findings, Mycofence presents a promising tool for enhancing aquaculture health and sustainability.

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