Oral fish vaccine wins "Crazy Idea"

Oral vaccines for fish developed at National Cheng Kung University have won the top prize in the ¡§2008 Crazy Idea¡¨ contest ¡X a biotech competition organized by the Industrial Development Bureau, government officials said yesterday.

At the award ceremony in Taipei on Oct. 15, the research team, led by professor Yang Huey-lang (·¨´f­¦), will receive medals and a cash prize of NT$400,000 (US$12,400).

The vaccines, which have already gained patents both in Taiwan and the US, have been under development for years before a breakthrough was achieved early last year, officials at the Tainan-based university said.

During the three-year experiments on nearly 60,000 cobias, the new vaccines helped raise the survival rate from around 40 percent to more than 80 percent, university officials reported. In optimal circumstances, the vaccines can further boost the survival rate to 86 percent, which is better than the 64 percent achieved by fish vaccines developed in some European laboratories, they said.

Conventional fish vaccines are delivered by injection, Yang said, adding that although these vaccines are quite effective, the cost and time to apply them increase tremendously when used in commercial aquaculture because the fish populations are usually very large.

On the other hand, while oral vaccines that are delivered by mixing them into fish food can lower costs and take less time, they are limited in terms of efficacy, he said.

Yang¡¦s team employed gene-engineering techniques to implant the vaccines into carrier bacteria, then fed the bacteria to plankton. The vaccine-carrying plankton were later fed to fish to induce immunities against pathogens.

Compared to other oral vaccines, Yang said, his team¡¦s vaccines have greater efficacy because each dose contained much more antigen, and it was much easier to modify the vaccine to induce immunity against new pathogens.