From Bio Journal - December 2023

Trend: Lively activities surrounding genome-edited fish

On October 24, the Ministry of Health, Labour and Welfare (MHLW) accepted a notification regarding a genome-edited Japanese flatfish from Regional Fish Institute Ltd. The company's activities have led to an activation of the development, aquaculture, and sales of genome-edited fish. This Japanese flatfish has had the anorexigenic leptin gene knocked out by genome-editing technology. Since the Ministry of Agriculture, Forestry and Fisheries (MAFF) has not yet accepted the notification, it has not yet been approved for commercialization, but this is only a matter of time. Three types of genome-edited fish: red sea bream, pufferfish, and Japanese flatfish have now been developed.

The red sea bream has had the myostatin gene, which suppresses muscle development, knocked out. Testbiotech, a German group of scientists, says the reduced body length and abnormal positioning of vertebrae make it a skeletal anomaly possibly constituting "torture" fish breeding, with its concomitant animal welfare issues. The pufferfish and Japanese flatfish have had the leptin gene, which suppresses appetite, knocked out and gain weight at an unusually rapid rate while still maintaining a good appetite. However, the leptin gene is so important to the living animal that disrupting it can cause problems.

Molecular biologist Masaharu Kawata points out that genome-editing technology intentionally causes disease and disability, but the extent of disruption caused by knockout of the leptin gene is extremely severe. He uses an experiment with zebrafish as an example to show what happens when the leptin gene is knocked out. As a result, Kawata points out, abnormalities occur in brain function, reproductive behavior, and immune responses. Activity is also weakened, fear is enhanced, diurnal rhythms are altered, and color perception is reduced.

In addition, the genome editing technology itself leads to off-targets that disrupt other genes as well as causing large-scale chromosome damage at locations where the DNA is spliced. These can result in great hindrances to life activities. It is this kind of fish that Regional Fish Institute Ltd and others are attempting to farm and sell.

Regional Fish Institute Ltd also has other developments in the works. On October 5, the company signed an agreement with Fukui Prefecture, Fukui Prefectural University, the Fukui Fisheries Promotion Center, and Kansai Electric Power Co., Ltd., to develop land-based aquaculture products such as chub mackerel and pink sea urchin, which are specialties of Obama, Fukui Prefecture, and are pushing forward with variety improvement through genome editing.

Already on June 27, Regional Fish, in a joint venture with NTT, launched a new company, NTT Green & Food Co., Ltd., and announced that, for the time being, it would promote the cultivation of epigenome-edited, high temperature-resistant Japanese flatfish in the Kyushu area and that it would cultivate the flatfish at 20 locations in 10 yearsf time. The company is already cultivating genome-edited pufferfish in Kushima City, Miyazaki Prefecture, and is expected to increase the number of affiliated farmers.

NTT Green & Food Co., Ltd. signed a land-based prawn farming agreement with Iwata City, Shizuoka Prefecture, on October 17. The plant is expected to produce about 100 tons of fish per year and is scheduled to start operation around summer 2024. Regional Fish is based on the Kyoto University aquaculture farm in Miyazu City, Kyoto Prefecture, and the aquaculture farm of Kinki University in Imizu City, Toyama Prefecture, where it is pushing forward with the development of genome-edited whiteleg shrimp. NTT has been developing algae as feed for fish and shellfish, so this appears to be a combined effort.

Euglena Co. to build full-scale manufacturing plant

Euglena Co., a venture company from the University of Tokyo that uses fats and oils extracted from the microalga euglena to produce jet fuel, biodiesel fuel, and bionaphtha, will close its demonstration plant in Yokohama and build a full-scale manufacturing plant in Malaysia in collaboration with companies from Malaysia and Italy. (Nikkei Biotech Online 2023/11/2)

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(English Index)