ANIMAL HEALTH

Feeding immunity: how algae and tiny crustaceans could revolutionise fish vaccination

Malaysia, 23 September 2025 | A new bioencapsulation technique achieves 100% survival in zebrafish trials, pointing the way towards scalable, non-invasive disease control in aquaculture

Nannochloropsis sp

Aquaculture may be entering a new era, driven by smarter, non-invasive and scalable immunization methods. Traditional injections – stressful, costly and limited target fish – are beginning to be consigned to the past.

Researchers at Universiti Putra Malaysia, Universiti Kebangsaan and the company Agro-BioTech have developed an innovative oral vaccine against vibriosis, a disease responsible for heavy economic losses across the sector.

The breakthrough lies in the bioencapsulation of the microalga Nannochloropsis sp,, genetically modified to produce a protein from the bacterium Vibrio harveyi, the pathogen behind vibriosis, one of aquaculture’s most damaging diseases. These microalgae are consumed by tiny crustaceans, Artemia, which in turn are a natural food source for fish. In this way, the vaccine is seamlessly integrated into the food chain, reaching the animals’ digestive system safely and without invasive procedures.

The process, known as bioencapsulation, triggers an immune response in fish, priming them to recognise and neutralize the real pathogen if exposed. The findings, published in the journal Molecular Biotechnology by a team led by researchers Nur Farhah Nabihan Ismail and Zetty Norhana Balia Yusof, are striking: zebrafish that received the vaccine recorded a survival rate of 100 per cent against infection, compared with just 40 per cent in non-immunised specimens.

Beyond the data, the innovation points to a potential paradigm shift in aquatic animal health. Oral vaccination, embedded in the feed, reduces animal suffering, enables the immunization of large populations from early stages, and could cut reliance on antibiotics-one of the most pressing challenges in intensive production.

That said, the method still faces hurdles. Development involves high upfront costs due to the genetic modification of the microalgae and the cultivation of Artemia, and there is a risk that efficacy could be compromised if fish do not consume the correct dose consistently. Even so, researchers agree this approach opens the door to more ethical and sustainable from aquaculture – one in which fish health is safeguard with the same care as farm productivity.