Immersion mucoadhesive cationic lipid-based nanovaccine enhances protective efficacy and immune responses in striped catfish (Pangasianodon hypophthalmus) against Edwardsiella ictaluri

Summary 

Striped catfish, scientifically known as Pangasianodon hypophthalmus, has gained significant recognition as a primary whitefish species in aquaculture worldwide. Its production has seen a remarkable increase to meet the global demand for seafood. This species holds crucial importance for many low to middle income countries (LIMCs), especially South-East Asia, as it serves as a vital protein source and generates essential income for numerous low-income families. However, the necessity for intensive farming methods to meet the rising demand has been impeded by several challenges, including substandard fish farming practices, water quality issues, and a surge in infectious disease outbreaks within aquaculture systems. Among these challenges, Bacillary necrosis of Pangasianodon (BNP), a recently identified disease caused by Edwardsiella ictaluri, has emerged as a significant infectious disease concern in intensive striped catfish production. E. ictaluri can affect fish of all ages, but it particularly leads to high mortality rates among fingerling and juvenile fish. During the initial stages of infection, BNP exhibits minimal external symptoms. Clinical signs become apparent shortly before death occurs. Affected fish swim slowly near the water's surface and, upon examination, display pale discoloration on their skin and gills. Additionally, internal examination reveals white spots on the liver, kidney, and spleen. Outbreaks attributed to BNP lead to complete mortality, reaching up to 100%, resulting in significant economic implications. This poses a threat to food security and undermines sustainability in aquaculture. Consequently, the primary approach currently employed to treat BNP is the administration of antibiotics. However, relying on drug application to combat disease outbreaks is expensive and raises significant concerns for both the environment and consumers. It is not a sustainable long-term solution to address the problem. Vaccination is a preferred strategy for managing infectious diseases in aquaculture, as it can effectively prevent disease, reduce economic losses caused by high levels of mortality, and decrease the reliance on antibiotics. Hence, researchers will develop a mucoadhesive cationic lipid-based nano-immersion vaccine for striped catfish (Pangasianodon hypophthalmus) against Edwardsiella ictaluri.