U.S. Department of Agriculture's National Research Initiative (NRI)

The global shrimp aquaculture industry expanded significantly throughout Asia and Latin America during the 1980's and this expansion was generated largely by abundant wild seed, static supplies of shrimp from capture fisheries, and high profits from cultured shrimp.

Despite high levels of production, shrimp farmers have suffered significant economic losses in recent years due to disease problems that have plagued the industry. Shrimp pathogens include viruses, bacteria, fungi, and protozoans, although viruses are the most significant.

Unfortunately, there are no commercially available chemicals, antibiotics, or vaccines to effectively treat viral diseases in shrimp. Systematic genetic selection of shrimp can enhance resistance to specific viral pathogens, although the long-term efficacy of this approach is unclear. In light of the significant disease challenges faced by shrimp farmers worldwide, there is an urgent need to develop effective technologies to mitigate crop loss from pathogenic agents.

With funding from the U.S. Department of Agriculture's National Research Initiative (NRI), researchers from the University of Connecticut and the Oceanic Institute are developing transgenic shrimp that posses gene constructs for cecropin. Cecropins are a family of antimicrobial peptides that were first discovered in silk moth (Hyalophora cecropia) pupae. Due to their unique structural features, cecropins can be incorporated into cellular membranes of bacteria, fungi and parasites, resulting in the formation of pores on the membrane leading to the inevitable fate of death of pro- and eukaryotic pathogens.

The long-term objective of this research program is to develop strategies for producing new shrimp strains that are resistant to pathogen infection. To do this, the research focuses on the manipulation of antimicrobial genes. We hypothesize that transgenic shrimp which express cecropin, or a synthetic analog, would exhibit enhanced resistance to pathogen infection.

To date, we have successfully produced transgenic shrimp carrying the cecropin gene. Future efforts will focus on producing an F1 generation of transgenic shrimp and, ultimately, challenging these shrimp with a suite of viral, bacterial, fungal, and protozoan pathogens to assess enhanced pathogen resistance.