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Researchers at the Massachusetts Institute of Technology (MIT) and the U.S. Department of Agriculture have developed a promising new approach to vaccinating farmed fish that could improve fish health, reduce labor requirements, and make vaccination safer for both fish and farm workers.

The technology uses water-resistant, food-grade silk microneedles designed to deliver vaccines through the skin of fish. The small, single-use devices lightly penetrate the skin, remain attached while fish swim, and gradually release their vaccine before decomposing.

The innovation could address several challenges associated with conventional fish vaccination. Current injection methods typically require fish to be sedated, removed from the water, and transported along a conveyor system where workers administer individual injections. The process can be labor-intensive, expensive, stressful for fish, and potentially hazardous to workers because of accidental needle sticks and the risk of disease transmission.

Alternative approaches, including medicated feed and immersion treatments, can also have limitations, particularly when it comes to ensuring that every fish receives an effective dose.

One particularly promising application involves early-life vaccination. Traditional needle-based vaccination is generally difficult to perform on fish weighing less than approximately 30 grams. However, the MIT research team successfully demonstrated that its microneedle technology could deliver vaccines to rainbow trout weighing as little as 1 to 2 grams.

The researchers also demonstrated that the devices could carry different types of vaccines, including bacterial and DNA-based vaccines, while allowing for controlled vaccine release. Another potential advantage is improved storage stability: the technology preserved approximately half of the DNA plasmids’ structure after four weeks under dry storage conditions, potentially reducing reliance on refrigerated transportation and storage infrastructure.

Although additional development and testing will be necessary before the technology can be implemented commercially at fish farms, the research represents an encouraging step toward more efficient disease prevention and improved animal health management in aquaculture.

The project was supported in part by MIT’s Abdul Latif Jameel Water and Food Systems Lab and the USDA.

Read More: MIT engineers design a safer, more efficient vaccination system for farmed fish