The Pacific white shrimp, Litopenaeus vannamei, reigns in global aquaculture and is valued for its rapid growth, adaptability to various salinities, and disease resistance. But even these resilient creatures can succumb to environmental stressors such as high levels of ammonia, extreme pH, and low salinity.
But how can we ensure that shrimp thrive in the face of environmental challenges? This is where selective breeding comes into play, allowing shrimp farmers to breed even more resilient and productive populations.
A team of researchers from the Sanya Tropical Fisheries Research Institute and the Chinese Academy of Fishery Sciences designed a study to create specific lineages of populations of Litopenaeus vannamei shrimp to evaluate resilience under stress conditions such as ammonia-N, pH, and salinity.
The challenge for the shrimp industry
The shrimp industry faces several challenges to ensure its sustainability in the future. The combination of high stocking densities and increasing extreme weather events induces stress and decreases shrimp growth and survival rates.
Ammonia stress leads to issues in the shrimp’s intestinal health, while environmental stressors (temperature and salinity) impact shrimp immunity. In this regard, it is necessary to have shrimp genetic lines resistant to stress conditions, to ensure the welfare of animals in culture, an increasingly widespread criterion.
The study
Selective breeding requires accurate estimation of variance components and genetic parameters of important traits. The study published in the journal Animals sheds light on this crucial process and reveals valuable information about the genetic components of stress tolerance in L. vannamei.
The scientists formed lineages from 20 full-sibling families of L. vannamei, with parents from Thailand and the United States. They then evaluated the genetic resilience traits of juvenile shrimp from these families under high levels of ammonia-N, high pH, and low salinity by conducting a 96-hour acute toxicity test.
Key findings
The results were promising: significant differences in stress tolerance were observed among families, indicating a clear genetic influence. This variability is key to selective breeding, as it allows breeders to identify and prioritize families with naturally higher resistance.
- Heritability matters: The study estimated the “heritability” of stress tolerance, essentially measuring the proportion of variation transmitted from parents to offspring. This information is crucial for predicting the effectiveness of selective breeding programs.
- Balancing act: The researchers also explored the complex relationship between growth and stress resistance. While some positive correlations were observed, suggesting that selecting one trait could benefit the other, the findings highlight the need for careful balance to avoid unintended consequences.
- Family favorites emerge: By comparing two selection criteria (genetic values and phenotypic values), three families (No. 2, 9, and 10) stood out as “potential champions” in terms of stress tolerance under specific conditions. These families are prime candidates for future breeding programs.
- Building the foundations: The most significant contribution of the study lies in establishing a model for estimating genetic parameters. This model allows breeders to predict genetic variations among different mating combinations, enabling a specific selection of stress-resistant shrimp.
What does this mean for the future of shrimp farming?
This research paves the way for the development of a stronger and more sustainable shrimp aquaculture. By incorporating stress tolerance into breeding programs, aquaculturists can breed shrimp with greater resilience to environmental challenges, leading to higher production, lower losses, and ultimately, a safer and more profitable industry.
But how do we use this knowledge? Scientists can use sophisticated tools such as genetic parameters and breeding values to understand and predict how traits (such as stress tolerance) will be transmitted. This information will enable shrimp farmers to make informed decisions, producing “resilient shrimp” generation after generation.
The research holds immense potential for the future of shrimp aquaculture. By incorporating genetic selection for stress resistance into improvement programs, we can:
- Reduce shrimp mortality due to stressful environmental factors, leading to increased production and economic benefits.
- Minimize the need for antibiotics and other interventions, promoting sustainable and environmentally friendly aquaculture practices.
- Ensure the long-term health and sustainability of the shrimp farming industry.
Conclusion
“Our findings lay a solid theoretical foundation for the selective breeding of Litopenaeus vannamei, providing valuable information for improving varieties and economic yields,” conclude the scientists.
This study is a step forward in optimizing shrimp breeding for resilience. Further research is needed to explore the underlying genetic mechanisms of stress resistance and refine selection strategies. By harnessing the power of genetics, we can unlock a future where shrimp farming thrives in harmony with the environment, ensuring a safe and sustainable source of protein for future generations.
The study was funded by Project of Sanya Yazhou Bay Science and Technology City, Industrial Technology System of Modern Agriculture, and the Central Public Interest Scientific Institution Basal Research Fund, South China Sea Fisheries Research Institute, CAFS.
Reference (open access)
Shi, Miao, Song Jiang, Jianzhi Shi, Qibin Yang, Jianhua Huang, Yundong Li, Lishi Yang, and Falin Zhou. 2024. “Evaluation of Genetic Parameters and Comparison of Stress Tolerance Traits in Different Strains of Litopenaeus vannamei” Animals 14, no. 4: 600. https://doi.org/10.3390/ani14040600
