Selenium Enriched Trionyx sinensis : A New Choice for the Sustainable

Bo YANG Wei HUANG Xianghui QIN Jun YAN Chengde LIN Xiaofeng GAO Yinglan HUANG

Development Model of Modern Agriculture

Abstract Based on the analysis of the current situation and existing problems of traditional Chinese soft shelled turtle ( Trionyx sinensis ) breeding industry, combined with the fact that selenium enriched functional agriculture is the future demand of mankind, this paper put forward the necessity of developing selenium enriched Chinese soft shelled turtles and promoting the sustainable development of modern agriculture: the development of selenium-enriched Chinese soft-shelled turtle is the need of the consumer market for food safety, the need to reduce the production cost of soft-shelled turtles and improve the production efficiency of soft-shelled turtles, the need to enrich the Chinese soft-shelled turtle market, and the need to promote the sustainable development of modern agriculture (fishery).

Key words Functional agriculture; Selenium enriched  Trionyx sinensis ; Modern agriculture; Sustainable development of agriculture; Countermeasure

Received: August 21, 2021  Accepted: October 22, 2021

Supported by Guangxi Science and Technology Program Project of China (GK AD19245169); Yulin City Scientific Research and Technology Development Plan Project (YSK 20204026, 2019Cxpt00A4, YSK 20202001, YSK 20204038).

Bo YANG (1979-), male, P. R. China, senior agronomist, devoted to research about functional agriculture.

*Corresponding author. E-mail: 363583837@qq.com.

Trionyx sinensis , also known as water fish, soft shelled turtles, round fish, Wang Ba,  etc. , is an oviparous amphibious poikilothermal reptile, as well as a common breeding turtle species［1］.  Chinese soft shelled turtles taste delicious and are rich in protein, vitamins and trace elements. It has been regarded as a tonic treasure for a long time. It has been loved by people since ancient times. The market demand is high and the price is rising all the way. In recent years, with the improvement of people’s living standards, people put forward higher requirements for healthy diet. The price of soft shelled turtles under the ecological breeding mode remains high and the economic benefit is obvious. The raising of selenium-enriched Chinese soft shelled turtles is to strengthen the selenium enrichment of Chinese soft shelled turtles, so as to effectively improve the selenium content in their bodies, which can not only stimulate their immune system and improve disease resistance, but also promote the growth, development and reproductive performance of Chinese soft shelled turtles. Even the bodies of the final product Chinese soft shelled turtles have become a selenium enriched functional food because they are rich in selenium. However, since the 1980s, although China’s turtle breeding industry has developed rapidly and formed a certain breeding scale, it has also brought serious diseases and affected the sustainable development of breeding. In particular, many farmers lack understanding of turtle breeding technology and disease prevention due to lack of scientific breeding knowledge. The yield of Chinese soft shelled turtles is relatively low, and there are many diseases, which reduce the quality of soft shelled turtles［2］. Therefore, realizing efficient and rapid breeding of soft shelled turtles and making them a selenium rich functional food as far as possible can not only make up for people’s demand for selenium rich products, but also is of great significance to the healthy and sustainable development of soft shelled turtle industry in China and even the world.

Problems in Traditional Turtle Culture

Although the breeding industry of Chinese soft shelled turtles in our region has developed rapidly and the breeding output has also increased significantly, due to the intensive artificial breeding of Chinese soft shelled turtles, their greedy and aggressive habits and many farmers’ lack of scientific breeding knowledge and lack of understanding of the breeding technology and disease prevention and control of Chinese soft shelled turtles, Chinese soft shelled turtles have a relatively low output and suffer from many disease, and the quality of Chinese soft shelled turtles is reduced. These problems are mainly given below.

Some turtle germplasms degenerates obviously

In recent years, the quality of soft shelled turtle fry has been greatly reduced, mainly due to the neglect of parental germplasm selection, serious inbreeding, and the inflow of some foreign soft shelled turtles into China, which directly affects the genetic gene bank of soft shelled turtles, thus affecting its germplasm purity, resulting in many diseases, large seedling differentiation, slow production speed and so on.

Turtle diseases are increasing year by year, and epidemic prevention and control are not in place

Due to years of breeding, many fish ponds are aging, and germplasm degradation, increased breeding density, deterioration of water environment and other reasons result in the increase of diseases and the emergence of new diseases. After the diseases of soft shelled turtles occur, many farmers are not sure about the disease diagnosis, drug selection and dose use, which leads to in misdiagnosis and improper drug use, resulting in death. Due to the lack of the concept of "prevention is more important than treatment", some farms makes active treatment only when diseases occur, so that the survival rate, commodity rate and profit cannot be guaranteed, and the breeding cost increases.

Poor market information for turtles makes it difficult for farmers to grasp the timing of seedling investment and listing

Only those farmers who analyze all kinds of information of the turtle industry, timely pay attention to market dynamics, and use all kinds of useful information to guide production and sales can have a greater chance to make money. Those farmers who invest blindly can only drift with the tide in the rapidly changing market and can make money when they are lucky. When the overall environment (economic environment) and small environment (turtle breeding industry) are in bad condition, a total loss may be caused.

Social services are not perfect and the degree of organization is not high

All localities should form the production and operation mode of "cooperatives (associations)+bases+farmers", which is organized from the aspects of fry supply, production and breeding, circulation,  etc. , so as to effectively strengthen information exchange, avoid some breeding risks, and better safeguard the interests of the industry. However, various associations are in their own ranks, and there is little contact between the associations, that is, there is a lack of communication and exchanges with each other, which further results in undesirable phenomena such as vicious price competition, speculation, blind breeding, and excess breeding.

The industrial structure is unreasonable and the technical level is low

The breeding of Chinese soft shelled turtles is mainly family based, and has the characteristics of small scale, scattered structure and low degree of industrialized management. The fry, breeding, circulation, feed, scientific research and other links are still in their own independent state, and there is mutual extrusion among farmers, enterprises and farmers and enterprises, which cannot form a competitive force. At present, the industrial chain of Chinese soft shelled turtles is relatively short. Most of the economic output value is created by the primary industry. It relies too much on the fresh sales of products, and does not form a pattern of integration of production, processing and marketing. The Chinese turtle processing industry and Chinese turtle leisure fishery are still blank, and the secondary and tertiary industries are seriously lagging behind.

The industrial growth rate is too fast and the breeding cost is too high

The scale of commercial turtle breeding industry is expanding year by year, resulting in "short supply". The market phenomenon has pushed up the breeding cost. First, the infrastructure construction cost of the new area is high. The construction of the outer pond of Chinese soft shelled turtles is about 10 000 yuan per mu. The standardized outer pond breeding pond needs to be built with cement tank wall and anti escape facilities, so the infrastructure construction cost of Chinese soft shelled turtles is high. Second, the price of fry is high. For example, the price of young soft shelled turtles in 2017 is 5.8 yuan/piece, the turtle fry of about 500 g for transferring to outer ponds in the greenhouse is as high as 80 yuan/kg, and the cost of turtle fry is nearly 30 000 yuan per mu of pond, which is very high. Third, the feed price is high. With the annual rise of the price of fish meal in the world, the high price of fish meal leads to the continuous rise of the feed price of Chinese turtles, and the feed cost of Chinese turtle has accounted for 60%-70% of the total breeding cost. The total investment cost of farmers is high, and 10 mu of turtle breeding ponds needs a cost investment of 300 000-500 000 yuan. Once the Chinese turtle market is bad, the farmers will face a loss, and the farmers who borrow from the bank will have a greater risk.

Develop selenium rich  T. sinensis  and promote the sustainable development of modern agriculture

The development of selenium-enriched soft shelled turtles is the need of food safety in the consumer market

Due to the low price of soft shelled turtles in previous years, the rise of feeding costs since last year and the occurrence of mumps (red neck disease), intestinal perforation disease and white floor disease (hemorrhagic intestinal necrosis disease) in some areas and other factors, the production situation of soft shelled turtles is not optimistic. Soft shelled turtle production is an important part of fishery and even agricultural development, and soft shelled turtles are the main non-staple food for many urban and rural residents. Through the construction of the project, vigorously developing the production of soft shelled turtle is of great significance to stabilize market supply, meet consumer demand, increase farmers’ income and promote economic development. Meanwhile, with the rapid development of economy during the exhibition, consumers’ safety awareness and brand awareness of agricultural products have been continuously strengthened, standardized turtle breeding has been promoted, and the production source has been standardized from the aspects of variety standardization, nutrition standardization, feeding standardization and drug use standardization, so as to provide consumers with "safe, high-quality and fresh" fishery food, which fundamentally protects the interests of consumers［4］.

The development of selenium-enriched soft shelled turtles is the need to reduce the production cost and improve the production efficiency of soft shelled turtles

Although the turtle breeding industry in our region develops rapidly, there is still a certain gap compared with the provinces with developed fisheries. The main reasons are: first, the varieties are poor and the popularization rate of improved varieties is not high; second, the breeding environment and turtle pond conditions are poor; third, the disease threat is great; and fourth, the production efficiency is low and the survival rate is relatively low. Through the implementation of standardized turtle breeding, selecting excellent varieties, first-class turtle ponds and equipment, advanced production management technology and disease prevention and control scheme to carry out standardized turtle production can maximize production efficiency［5］.

The development of selenium-enriched soft shelled turtles is the need to enrich the  T. sinensis  market

In recent years, the turtle breeding industry in our district has developed rapidly, but due to the single variety in turtle production, it cannot meet the needs of consumers at different levels. Meanwhile, there are a series of problems such as low degree of intensification and standardization, backward production technology level of turtle breeding, lack of scientific management and so on, resulting in poor meat quality and prominent safety problems,

which seriously restricts the further development of turtle breeding industry. Moreover, healthy turtle breeding is directly related to the health of the people. We should change the concept of breeding, adjust the breeding mode, and expand and strengthen the fishery industry. The state will expand the scale of subsidies for breeding bases, increase investment in animal disease prevention and control, strengthen the construction of grass-roots veterinary teams, improve the monitoring and emergency response mechanism for major animal diseases, and establish and improve the animal identification and disease traceability system.

The development of selenium-enriched soft shelled turtles is the need to promote the sustainable development of modern agriculture (fishery)

According to the experience of gradually improving the modern production level of foreign fisheries and the direction of domestic fisheries development, large-scale, intensive and standardized turtle farms are the long-term development goal of fisheries. Establishing a relatively standardized and strictly managed soft-shelled turtle breeding base of a certain scale with complete breeding facilities, unified technical regulations and measures and supporting manure treatment is the primary task of promoting fishery industrialization. It is of great significance to improve the professionalization, scale and standardization of aquaculture and to ensure the safety of fishery products.

The breeding of soft shelled turtles in Guangxi is still dominated by decentralized breeding, and the processing industry of soft shelled turtle products develops slowly. Most soft shelled turtle products are primary products, and the development of processing industry lags behind the production development. Chinese soft-shelled turtle breeding system and extension service system are lagging behind, and the proportion of good Chinese soft-shelled turtle varieties is not high. Problems of insufficient funds for large-scale development, lack of professional and technical personnel at the grassroots level, few research and development of new varieties and new technologies and difficulties in popularization exist. The management and regulation system of the fishery industry is not sound, and the production and marketing profits are upside down.

Conclusions

Only by promoting the high-efficiency and large-scale breeding technology of soft shelled turtles can we accelerate the transformation of fishery production mode, strengthen the construction of modern fishery support and protection system, deepen structural adjustment, optimize regional layout, build a modern fishery industry system, take the sustainable development road of high-quality, high-efficiency, safety, ecology and recycling, and promote the sustainable development of fishery in the whole region.

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