In the battle against one of the most devastating diseases affecting Atlantic salmon, a glimmer of hope has emerged from the labs of the Atlantic Veterinary College at the University of Prince Edward Island. Researchers, led by Dr. E Fajei, have uncovered promising results in the fight against Enteric Red Mouth (ERM) disease, a bacterial infection that has long plagued the aquaculture industry. Their findings, published in Comparative Immunology Reports, suggest that a novel feed additive could significantly boost the immune response of salmon, potentially revolutionizing the way we combat this pervasive pathogen.
ERM disease, caused by the bacterium Yersinia ruckeri, has been a thorn in the side of salmon farmers for decades. The disease can lead to high mortality rates, causing significant economic losses for the industry. Traditional methods of control have often relied on antibiotics, but the rise of antimicrobial resistance (AMR) has made this approach increasingly unsustainable.
Enter PACAP-38, a polypeptide that has shown promise in modulating the immune response in various species. Dr. Fajei and her team set out to investigate whether this compound could offer protection against ERM disease in Atlantic salmon. “We were particularly interested in PACAP-38 because of its known anti-inflammatory and cytoprotective properties,” Dr. Fajei explained. “We hypothesized that it could help salmon mount a more effective response to Y. ruckeri infection.”
The study involved feeding Atlantic salmon one of three diets: a standard commercial feed, the same feed supplemented with an amidated form of PACAP-38, or the feed supplemented with a non-amidated form of PACAP-38. After 28 days, the fish were exposed to Y. ruckeri, and their immune responses were monitored over the following 20 days.
The results were striking. Salmon fed the amidated PACAP-38 diet showed a significantly higher survival rate compared to those on the standard diet. “We saw a clear difference in survival rates, which suggests that the amidated form of PACAP-38 is particularly effective in enhancing the salmon’s immune response,” Dr. Fajei noted.
But the benefits didn’t stop at survival rates. The researchers also observed changes in the expression of key immune genes. Both forms of PACAP-38 induced the expression of genes associated with inflammation and immune response, such as il1ß, hepc, and il10. Notably, the amidated form seemed to stimulate these genes earlier and maintain their expression longer, which could contribute to a more robust and sustained immune response.
So, what does this mean for the future of salmon farming? The findings suggest that PACAP-38, particularly in its amidated form, could be a powerful tool in the fight against ERM disease. By enhancing the salmon’s natural immune response, it could reduce the need for antibiotics, helping to combat the growing problem of AMR. Moreover, the potential economic benefits are substantial. Lower mortality rates and reduced reliance on antibiotics could lead to significant cost savings for the industry.
But the implications don’t stop at ERM disease. The anti-inflammatory and cytoprotective properties of PACAP-38 suggest it could have broader applications in aquaculture, potentially protecting against a range of pathogens. As Dr. Fajei puts it, “This is just the beginning. We’re excited about the potential of PACAP-38 and look forward to exploring its applications further.”
The study, published in Comparative Immunology Reports, titled “Investigation of two different PACAP-38 formulated feeds on Atlantic salmon immune responses with Enteric Red Mouth disease,” marks a significant step forward in the quest to protect one of the world’s most valuable fish species. As the aquaculture industry continues to grow, innovations like this will be crucial in ensuring its sustainability and profitability. The research opens up new avenues for developing feed additives that can bolster the immune systems of farmed fish, reducing the need for antibiotics and mitigating the risks associated with disease outbreaks. The future of salmon farming is looking brighter, one feed additive at a time.