Current Situation
In today’s highly competitive global market, genetic improvement emerges as a crucial tool to enhance shrimp production efficiency and maintain market competitiveness, especially in larval production. The shrimp industry continues to face significant challenges due to the high supply and pressure on market prices. Countries in the Americas and Asia have increased shrimp production without a corresponding rise in demand, resulting in the lowest prices in decades.
Genetic improvement can significantly boost shrimp production efficiency by selecting shrimp lines with faster growth rates and better resistance to diseases and environmental conditions. These improvements accumulate generation after generation, increasing efficiency per unit area and maintaining market competitiveness by reducing production costs.
Impact of Genetic Selection
Genetic improvement in shrimp extends beyond growth and grow-out phases to reproductive parameters such as the number of spawns per cycle and the number of eggs or nauplii per female. This leads to more efficient broodstock, cost reduction, and increased profitability over the long term.
Recent research indicates that improvements in spawning frequency can be inherited at rates ranging from 15% to 37%. Similarly, enhancements in the number of eggs and nauplii per female are heritable at rates of approximately 17-26% and 18%, respectively. This implies that genetic selection programs can effectively boost these parameters, increasing productivity and significantly reducing hatchery costs.
Animal welfare is another critical aspect. Traditionally, many hatcheries use eyestalk ablation (removal of an eyestalk) to increase female productivity. However, this practice negatively impacts shrimp by shortening their productive lifespan, increasing mortality, and raising disease prevalence. Genetic selection offers a non-intrusive alternative to improve female productivity without such adverse effects. Moreover, genetic improvement programs focused on growth can indirectly enhance female productivity, positively impacting hatchery efficiency. This is supported by a strong positive correlation (>90%) between female weight and the number of eggs and nauplii produced per spawning.
Genetic information also helps manage inbreeding in broodstock, which can negatively affect growth and survival during larval development and grow-out. Although the effect of inbreeding on reproductive parameters has not been extensively studied, it is significant. A 10% increase in female inbreeding has been observed to reduce egg fertilization rates by 3.0% to 26.0% and decrease nauplii numbers by 2.9% to 24.6%. Managing inbreeding through genetic monitoring and strategic crosses is essential.
Implementation of Genetic Selection Programs
The “Center for Aquaculture Technologies” (CAT) specializes in implementing genetic improvement programs tailored to the characteristics and needs of clients and the market. These programs use genetic information (genetic markers) to generate data for mass selection, pedigree, or genomic selection programs, aiming to improve key phenotypic traits for the client.
Selecting productive traits such as growth and survival during grow-out is indispensable for adding value for those using the produced larvae. However, selecting reproductive traits can be crucial to reducing costs and increasing productivity. A genetic selection program should focus on generating data associated with these traits to include them in selection models. This will allow for improvements in multiple productive traits by optimizing the design of crosses, selecting animals with the best genetic and phenotypic potential. Proper management will ensure the control of genetic diversity and inbreeding within the population, in addition to generating improvements in multiple traits of interest.
Steps to Establish a Genetic Improvement Program
- Define Objectives: Determine the traits to improve (e.g., growth rate, disease resistance, reproductive efficiency).
- Baseline Assessment: Conduct a Genetic Overview (GO) to characterize current genetic diversity, inbreeding levels, and relationships within the shrimp population.
- Select Genetic Markers: Choose appropriate genetic markers (e.g., SNP panels) for tracking genetic variations and guiding selection.
- Design the Genetic Selection Program: Develop a breeding strategy that includes mass selection, family-based breeding, or genomic selection based on your objectives and resources.
- Implementation: Start selecting and breeding shrimp based on the identified markers and desired traits.
- Monitoring and Adjustment: Continuously monitor genetic progress and adjust the breeding program as needed to ensure ongoing improvement and sustainability.
Measurable improvements in productivity and cost reduction can vary based on species, breeding program, and initial genetic diversity. Generally, initial improvements can be seen within one to three generations. Continuous monitoring and adjustments can further enhance these gains over time.
Initial Costs
The initial costs of implementing a genetic improvement program include:
- Genetic Analysis: Costs for conducting a genetic overview and developing SNP panels.
- Program Design: Expenses for designing and establishing the genetic program.
- Operational Costs: Ongoing costs for maintaining the breeding program, including data collection, analysis, and monitoring.
While there are costs to set up and run, the return on investment (ROI) in the medium to long term is significant due to improved productivity and reduced production costs.
Ongoing Research and Collaborations
Ongoing research projects and collaborations at CAT continue to push the boundaries of shrimp genetics. For example, high-density SNP panels for shrimp genotyping have been developed, integrating data from over 20 shrimp populations worldwide. These panels provide precise genetic analysis and support sophisticated breeding programs.
Research also includes exploring genomic selection and genome editing technologies to further enhance shrimp breeding. By focusing on traits like growth, disease resistance, and reproductive efficiency, these efforts aim to make significant strides in improving shrimp production.
One promising area is genome editing, which allows for precise modifications of shrimp DNA to enhance desirable traits. Research labs, such as those at CAT in San Diego, are at the forefront of developing these technologies, with the potential to revolutionize shrimp farming in the near future.
Conclusion
Genetic improvement is vital for increasing production efficiency and maintaining competitiveness in the shrimp industry. By focusing on producing robust, disease-resistant shrimp with better reproductive parameters, the industry can tackle current challenges and secure a sustainable future. CAT can help establish a comprehensive genetic improvement approach, benefiting producers by reducing costs, increasing profitability, and promoting sustainable and ethical shrimp production.
By leveraging genetic technologies and ongoing research, shrimp farming can evolve to meet the demands of a growing market while ensuring sustainability and economic viability. Genetic improvement programs, when correctly implemented, offer a powerful tool for achieving these goals, paving the way for a more efficient and resilient shrimp farming industry.
