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Chinese Academy of Sciences academician GUI Jianfang: Eating fish without being picky may become a reality

For 20 years, China's aquaculture production has accounted for about two-thirds of the world's aquaculture production and provided more than one-third of the animal protein sources for Chinese consumers.

At present, the genetic improvement rate of aquaculture is 52.8%, the contribution rate of the improved varieties to the increase of aquatic production is 25% to 30%, the lower than that of the developed countries such as Norway, aquaculture.

"Based on the continuous development of genome technology, precision breeding can accurately create excellent economic characteristics and varieties of fish, and cultivate the 'perfect fish' with good meat quality, high yield, less disease and fast reproduction." "Eating fish without being picky will hopefully become a reality."

Academician of Chinese Academy of Sciences

GUI Jianfang

Precision breeding

Crack the secrets of fish reproduction

Fish and other aquatic products are recognized as relatively high quality protein sources in the world. As the world's largest fishing country, China has accounted for about two thirds of the world's aquaculture output and provided more than one third of the animal protein sources for Chinese consumers over the past 20 years.

The sustainable development of aquaculture cannot be separated from the support of fine varieties. With the progress of the scientific research on genetic breeding, aquaculture in our country gradually got rid of the dependence on wild species. At present, there are about 550 aquaculture species in China, among which there are about 280 indigenous species with a certain aquaculture scale, about 80 introduced species and about 200 artificial cultivated varieties.

The cultivation of new fish varieties has greatly promoted the rapid development of related aquaculture. The output of crucian carp and carp has increased from 48,000 and 86,000 tons in 1983 to 2.749 million and 2.896 million tons in 2020. Carp, crucian carp, tilapia, Chinese prawn, scallop and other new varieties have been formed, realizing the upgrading of varieties.

What challenges does aquaculture breeding face? GUI Jianfang, an academician at the Chinese Academy of Sciences and a researcher at the Institute of Hydrobiology at the Chinese Academy of Sciences, told Outlook.

First, we will increase the rate of good seed production. At present, the genetic improvement rate of aquaculture is 52.8%, and a large number of aquaculture species have yet to be systematically improved. The contribution rate of improved varieties to the increase of aquatic production is 25%-30%, which is lower than that of the developed countries such as Norway.

The second is to reduce the incidence of disease. The annual loss of aquaculture is 45 billion yuan due to diseases. The improper use of drugs brings hidden dangers of product quality safety and pollution of aquatic ecological environment. "Based on the continuous development of genome technology, precision breeding can accurately create excellent economic characteristics and varieties of fish, and cultivate the 'perfect fish' with good meat quality, high yield, less disease and fast reproduction." "Eating fish without being picky is expected to become a reality," GUI said.

The basic formation of modern aquatic products

Improved seed and seed industry system

Outlook: How to evaluate the development of aquaculture industry?

Because there are few freshwater fishes in foreign countries, most of the good varieties of freshwater fishes in China come from independent research and development, and the seedlings are basically completely self-sufficient.

By stage, aquaculture industry in our country has experienced three major stages: mainly fishing for natural seedlings, mainly simple artificial reproduction and application of genetic improvement. In 1958, "four you fish" artificial breeding and successfully growing seedlings by natural light of kelp, symbolized that our country aquaculture industry enters the second stage. In 1991, the Ministry of Agriculture started the construction of aquatic original improved seed system, marking the third stage of aquatic seed industry. In the 21st century, in order to control the source of new variety breeding, a number of aquatic genetic breeding centers have been selected and identified for specific aquaculture species. Through these measures, the basic formation of China's modern aquatic seed improvement and seed industry system.

By 2019, China had set up 31 aquatic genetic and breeding centers, 84 state-level and 820 local aquaculture seed farms. At present, 240 new varieties of aquatic products have been adjudicated in our country, which drive the vigorous development of aquaculture industry.

Outlook: What scientific research has been carried out in China to improve the rate of aquaculture seeds?

There are many reasons for the low rate of improved aquaculture. First, in order to meet the diversified consumption needs of Chinese people, there are about 550 kinds of aquaculture. Some aquaculture species are still in the use stage; Second, the breeding cycle of some traditional breeding objects is long, and the new varieties are difficult to breed. For example, among the "Sidashuyu", only two new varieties of silver carp and Jinpon have been approved, while the new varieties of grass carp, black carp and bighead carp have not been approved. Third, the promotion of improved varieties is insufficient, and so on.

The research on genetic breeding of aquatic biology has always been the key work in the field of aquatic science. During the 12th Five-Year Plan period (2011-2015), the Ministry of Science and Technology successively deployed 973 program projects such as "Basic Research on Functional Genome and molecular Design Breeding of Important Cultured Fish", 863 program projects such as "Mariculture Seed Project", and national science and technology support projects such as "Research and Demonstration on Breeding and Large-scale Breeding Technology of freshwater aquaculture Varieties" during the 12th Five-Year Plan period. The Ministry of Agriculture and Rural Affairs has set up research projects in the public welfare industry (agriculture), such as "Research on Gender Control and Cultivation Technology of single sex Fish seedlings" and "Establishment and Application of common Technology for Molecular Breeding of aquatic Products", as well as projects to build a national aquatic germplasm resources platform. Since 2018, the Ministry of Science and Technology has deployed the national key research and development program "Blue Granary Science and Technology Innovation".

Under the support of these projects, genetic breeding of aquatic products has developed rapidly on the basic theory, technology and variety creation system. Since 2010, the whole genome sequences of dozens of aquaculture organisms such as oyster, carp, grass carp and half-smooth tongue sole have been successively deciphered, which establishes the international leading position in the genome research of aquatic organisms in China. It is mainly reflected in the following three aspects:

First, some important progress has been made in the identification of key functional genes and the analysis of genetic mechanisms around important economic traits such as growth, reproduction, sex, endocrine regulation, disease resistance, hypoxia tolerance, cold tolerance and quality.

Second, selective breeding, cross breeding, molecular marker-assisted breeding, cell engineering breeding, sex control, gene transfer and other technologies have been used in a variety of aquaculture organisms, and frontier technologies such as whole-genome selective breeding, molecular design and molecular module design breeding, and gene editing have been tried and applied.

Third, a genome-wide selective breeding platform for aquatic organisms was built to produce scallop "Penglaihong 2" Chlamys farreri. Gene editing technology has also been applied in a variety of farmed or ornamental fish, such as silver crucian, yellow catfish, carp, blunt bream, goldfish, etc., speeding up the process of precision breeding.