This project belongs to the field of aquaculture technology. my country's river crab breeding industry has developed rapidly, with annual output growing from 17,500 tons in 1993 to 700,000 - 800,000 tons in recent years, with an output value of 40 - 50 billion yuan. Although the scale and output continue to increase, the quality of river crabs has generally declined. The main reason is that feed is fed at will and varied in production, and low-quality feed or raw materials are often used and a large number of frozen fresh fish are used, which can easily lead to deterioration of water quality in ponds and cause low quality and efficiency of river crab cultivation. It has become the main bottleneck for the healthy development of the river crab industry. In response to the main problems and technical needs of this industry, the project team teamed up with the advantageous departments in my country's research and development and promotion and application of river crab, and conducted systematic and in-depth research on key technologies for ecological breeding of high-quality river crab with the whole process of feeding compound feed and quality control as the main line., revealing the relationship between feed nutrition regulation and high-quality river crab breeding, and building a "high-quality river crab ecological breeding technical system based on full-process compound feed and nutrition regulation". It provides technical support for my country's industrial upgrading from "large-scale crab farming" to "high-quality crab farming".

1. Scientific and technological innovation points
   (1) Clarified the theoretical relationship between feed nutrition regulation and high-quality river crab breeding: clarified the important role of feed nutrition, especially fat nutrition regulation, in high-quality river crab breeding; clarified the relationship between the smell, taste (i.e. flavor) of river crab and its related nutritional composition, revealing the material basis and scientific meaning of traditional high-quality river crab: "fat, fragrant, fresh and sweet"; For the first time, an evaluation system for the nutritional quality and flavor of river crabs was established. Through pilot experiments, the effect of feed nutrition control on improving the nutritional quality of river crabs was evaluated.
   (2) Supplements and improves the nutritional requirements map of river crab breeding stages: Through research on nutritional physiology, nutritional requirements and nutritional regulation, especially the effects of essential nutrients and trace elements on improving the growth, immunity, reproduction, and stress resistance of river crab (hypoxia, high ammonia nitrogen, high pH, sexual precocity, etc.) and nutritional quality, combined with the utilization and development of new feed sources, the feed formula has been optimized, laying the foundation for full-price feed formulation based on nutritional regulation.
   (3) Comprehensively build a technical system for ecological breeding of high-quality river crabs based on the whole process of feed: First, environmentally friendly full-price feed formula and processing technology. In breeding, it not only completely replaces traditional cultured frozen fresh fish and low-quality raw materials, but also ensures the high quality and environmental ecology of cultured river crabs; the second is the supporting breeding technology of full-process compound feed feeding. Through technologies such as high-quality seedling cultivation, water quality control (bottom aeration and microbial preparations), and scientific feeding, river crab breeding technology has been standardized to ensure the stability of river crab breeding quality; the third is river crab quality control and evaluation technology. Combining technologies such as salinity and fat nutrition control to improve the quality of river crabs, a practical technology to evaluate the nutritional quality of river crabs from five aspects: artificial senses, intelligent senses, nutritional components, odor and taste substances has been built.
   The above inventions and innovations have been evaluated through novelty search, consultation and evaluation, and the comprehensive technology of the results has reached the international leading level.

2. Intellectual property and talent training
   Obtained 10 authorized inventions and 10 utility model patents; 1 computer software copyright, 2 local standards, published 131 papers (39 included in SCI), with a total of 435 citations; participated in the compilation of 2 teaching materials; and trained 12 doctors and more than 30 masters.

3. Promote and apply results
   The project adopts a research, development and promotion approach, and relies on the support of more than 20 national, provincial and ministerial projects such as the Ministry of Science and Technology's Spark Major Project, Agricultural Technology Transformation, and Shanghai Science and Technology Promotion to Promote Agriculture, accelerating the maturity and promotion of technology research and development. The results have not only been widely promoted in the main breeding areas in the middle and lower reaches of the Yangtze River, but also expanded to relevant provinces and cities such as Taiwan, Guizhou and Yan 'an in my country according to local conditions. In the past three years, a total of 1.097 million acres have been promoted, with an added output value of 2.27 billion yuan. It has become an important way for farmers in western China to get rid of poverty and become rich. It is also the first time that the mainland's agricultural technology system has been successfully transferred to Taiwan as a whole, becoming a model for cross-strait agricultural cooperation; the developed river crab feed full-price preparation technology has been industrially applied in many feed companies, and has achieved significant economic and social benefits.