A SURVEY OF CHINESE GIANT SALAMANDER (ANDRIAS DAVIDIANUS)

Chinese giant salamander (Andrias davidianus) is an endemic species in China, commonly known as baby fish, pike and foot fish. It is a national second class protected aquatic wild animal, and also a key development species of agricultural industrialization and characteristic agriculture. Chinese giant salamander is mainly distributed in the Yellow River Basin, the Yangtze River Basin and the Pearl River water system. Qinling region of Shaanxi Province is the largest production area of Chinese giant salamander. In June 2010, the Ministry of Agriculture awarded the title “hometown of Chinese giant salamander” to Hanzhong City, Shaanxi Province. Chinese giant salamander has a high economic value, and has a wide range of development and utilization prospects in food, health care, medicine, ornamental and other aspects, so it is quite concerned by the community. In recent years, the scientific research on Chinese giant salamander involves many aspects, including disease, pathogen, immune response, physiology, stress response, tissue development, genetics, evolution, protection and development, etc. This paper reviews these aspects.　　According to the original infectious diseases, the diseases of Chinese giant salamander can be divided into viral diseases, bacterial diseases, fungal diseases and parasitic diseases. After being infected by pathogens, Chinese giant salamander will produce immune response, which can be divided into specific and non-specific. The latter plays the role of the first line of defense against pathogen invasion. Therefore, the research on immune response of Chinese giant salamander mainly comes from non-specific immunity. Chinese giant salamander has the characteristics of longevity, cold tolerance and skin respiration, which is an ideal model for studying the evolution of local adaptation. Transcriptome analysis is very useful for studying the complex genome and physiological functions of amphibians. The application of molecular biology technology has greatly enriched the research on the gene level of A. davidianus. We know that there are three species of giant salamander in the world. The other two are Cryptobranchus alleganiensis and A. japonicus. In the United States, there are basically no artificially cultured giant salamanders, and the research on giant salamanders is more about how to carry out field protection and rescue work. Japan’s policy on A. japonicus is that both wild and artificial breeding should be protected and not allowed to be traded, which is different from that of China. In China, wild giant salamander is a second-class protected animal. In order to protect its population, only the second generation of artificially bred giant salamander can be traded. However, it is difficult to distinguish wild and cultured giant salamanders from the appearance, which leads to the contradiction between protection and trade. There are more than 70 kinds of natural active substances in the muscle of A. davidianus, which can promote human physiological activities, improve physiological metabolism, promote protein synthesis, regulate human immune function, and enhance human resistance to disease. The food developed from giant salamander has the effect of nourishing blood and intelligence, and has auxiliary therapeutic effect on neurasthenia, anemia, dysentery, malaria and other diseases. Therefore, giant salamander has a broad development prospect in the medical and health care industry. In addition to the above, there are other aspects of research on giant salamander, such as extract research, breeding technology research, body element analysis and population genetics research.　　To sum up, the research on A. davidianus from different angles is very rich. With the application of molecular biology technology, both the research on the disease and the physiological development of A. davidianus have carried on deeply from characterization to mechanism. From the existing research results, there are many reports on the genomics of A. davidianus, which reflects a hot spot and trend of giant salamander research. By studying the structure, function, evolution, localization and editing of the genome of A. davidianus, we can further explore its impact on A. davidianus. It can also be used for overall characterization, quantitative analysis and comparison of different genomes of A. davidianus, and study some phenomena in the genome, such as epigenetic regulation effect (the influence of one gene on another gene), pleiotropy (one gene regulates multiple traits), and the relationship between gene loci and alleles in the genome, which can explain the physiological reactions of A. davidianus. It provides a theoretical basis for the phenotype characteristics of A. davidianus, and also lays a foundation for further research in the future. China’s giant salamander industry has experienced a series of ups and downs, and eliminated a number of small workshop type enterprises. At the same time, some enterprises have also got experience and become the industry leader. Some giant salamander enterprises have developed nearly 100 giant salamander products, such as giant salamander longevity noodles, oligosaccharide peptide fruit drinks, giant salamander rice noodles, giant salamander canned products and skin care products. In addition, some enterprises have cooperated with well-known pharmaceutical enterprises to develop maternal and infant products such as giant salamander pregnant women′s health products and infant rice paste. Some companies have successfully listed on the “new third board”, established “T-mall” flagship stores to develop e-commerce teams, and others have successfully listed overseas and established WeChat business teams, with good development momentum. Looking forward to the future, under the guidance of these well-known enterprises, Chinese giant salamander industry will develop steadily, and more products can go abroad and go to the world.