Introduction

For our 2019 iGEM project, we focused on designing a bacterial strain that provide immunity in Koi fish against koiherpes virus (KHV). To save Koi from this often-fatal disease with the vaccine we engineered, we want to make sure our design of the whole system is practicable and can be applied and made in real fish drug industry. Therefore, we interviewed our school Head of Operation Mr. Wang to know more about our own school Koi breeding, after thatat consulted with experts in Shanghai Ocean University with technical issues we faced during experiment design. Finally, we went to the Shanghai Aquaculture Exhibition to talk to people who work in Koi fish market to collect more info on Koi business and got valuable feedback from them.

Koi pond inside our school｜May 17th, 2019

As we got our iGEM project inspiration from our own school Koi pond, the first person we interviewed was our school head of operations Mr. Wang, as he can give us the first-hand information about Koi breeding. We asked Mr. Wang specifically about the pond maintenance, the relevant cost of running the pond and fish raising (fish food etc.), the mortality rate of fish and whether the fish are getting any kind of vaccination. According to him, they feed fish every morning with fish food that containing amylose and lecithin in the ingredients that will boost the fish immune system. They also clean the pond every 2-3 months to keep the water clean. In the first few years, the school spends 2000-3000 RMB per year on purchasing new fish due to some fish died throughout the year. According to Mr. Wang, in 2017 the mortality rate of the fish was very high that they had to spend almost 3 times money on purchasing new fish than regular years. This, Mr. Wang said, might due to the extreme hot weather that summer and lack of pond cleaning that made the water quality got bad. Since the incident, they started to pay more attention on pond cleaning and the mortality rate went down significantly since then. When we asked Mr. Wang if they vaccinate the fish against any disease, the answer was no. The Koi the school purchased were the cheap ones, so they think the fish food that containing the immune system boost ingredient will be enough for our Koi.

Ocean University｜July 17th, 2019

After talking to Mr. wang and knowing more about Koi breeding, SUIS Shanghai IGEM team planned a meeting with Professor Chen Zai Zhong and Professor Gao Jian Zhong at Shanghai Ocean University to discuss our project design. Professor Chen has many years of experience in ornamental fish breeding and Professor Gao is specialized in prevention and control of aquatic animal diseases.

(Although both professors expressed strong interest in our project, Professor Gao expressed concern toward the availability of synthesizing antibodies inside the fish gut. Gut is a complicated system where many different types of bacteria coexist, so they cannot be sure if specific antibodies can be expressed and the exact amount will they be expressed in gut. Given that only forms of amino acid can be taken in into gut and amino acid does not have antigenicity. How to synthesis giant protein that can be identified by white cells and triggered the immune responses is a problem to solve. Professor Chen also pointed out that despite the model of iron Qs system can theoretically express target protein, but there are other gene expressions happened in the gut that may disturb the synthesis of antibodies.) (No idea)

Shanghai International Aquaculture Exhibition｜August 28th, 2019

After completing the design of the experiments, we want to know more about Koi breeding from the Koi fish market to decide the best way of vaccination.

We found out that the Shanghai International Aquaculture Exhibition was going to be held in late August, where all business sectors that related to aquatic product will attend. It would be the perfect place for us to reach to Koi fish breeding companies. We've been able to talk to many people that own Koi fish farms and ask them specifically about the most effective method of vaccination for different scale fish and which method they prefer to use the most.

According to them, as Koi can live for over 70 years and sell for very high price in the market, they spend big amout of money in keeping the Koi healthy every year, and vaccine always plays an important role in it. To appropriately give the vaccine, timing and method of vaccination also need to be considered. They suggested making oral vaccine for their low cost and high efficiency. Unlike injection, which may lend pressure or physically harm the fishes, oral vaccination is also the safest compare to other methods.

We are also very lucky that one of the fish drug company showed strong interests in our recombinant bacteria idea and willing to talk to us deeply in the future on making the vaccine into real sample once we proved our experiment worked as although they have been working on making fish drug and vaccine for many years, our idea of using a promoter to control the expression of the antigen with live attenuated vaccine-carriers is still brand new and full of potential.