International Journal of Molecular Veterinary Research, 2025, Vol.15, No.1, 43-50 http://animalscipublisher.com/index.php/ijmvr 43 Research Insight Open Access Genetic Diversity and Selection of Disease-Resistant Tilapia Strains Linhua Zhang1, FanWang2 1 Institute of Life Sciences, Jiyang Colloge of Zhejiang A&F University, Zhuji, 311800, Zhejiang, China 2 Aquatic Biology Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, Zhejiang, China Corresponding author: fan.wang@cuixi.org International Journal of Molecular Veterinary Research, 2025, Vol.15, No.1 doi: 10.5376/ijmvr.2025.15.0005 Received: 08 Jan., 2025 Accepted: 10 Feb., 2025 Published: 25 Feb., 2025 Copyright © 2025 Zhang and Wang, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Zhang L.H., and Wang F., 2025, Genetic diversity and selection of disease-resistant tilapia strains, International Journal of Molecular Veterinary Research, 15(1): 43-50 (doi: 10.5376/ijmvr.2025.15.0005) Abstract In aquaculture, tilapia is widely farmed due to its high yield and strong adaptability. However, frequent diseases have restricted the development of the industry. To enhance disease resistance, this study evaluated the genetic diversity of multiple tilapia strains and screened potential disease-resistant superior germplasms based on molecular markers, phenotypic data, etc. The results show that, there are significant genetic differences among different strains, and some strains exhibit high disease resistance and genetic stability. Further selection experiments have shown that, the comprehensive utilization of genetic diversity information and phenotypic disease resistance evaluation can help accelerate the breeding process of disease-resistant strains. This study not only enriches the genetic resource database of tilapia, but also provides scientific support for the construction of an efficient disease-resistant breeding system, which has industrial promotion significance. Keywords Tilapia; Disease resistance; Genetic diversity; Genomic selection; Molecular breeding 1 Introduction Tilapia (Oreochromis spp. and allied genera) is among the most intensively cultivated fish globally, being commonly known as the "aquatic chicken" due to its high growth rate, good feed conversion, and tolerance of varied aquaculture conditions. Global tilapia production has risen continuously over the last two decades to well over 6 million tonnes per year, valued in the tens of billions of US dollars. The species is produced in more than 120 nations, whose main contributors are China, Indonesia, Egypt, Bangladesh, Vietnam, and Thailand for the majority of the global production. Apart from its economic value, tilapia is also a pillar of food security and rural livelihoods, particularly in middle- and low-income countries, where it provides quality, accessible animal protein (Kayansamruaj et al., 2023). Though its generic name as a hardy species, tilapia industry is facing increasing pressure from infectious disease. Bacterial pathogens such as Streptococcus agalactiae, Streptococcus iniae, Aeromonas hydrophila, Francisella orientalis, and Edwardsiella spp. are frequently associated with high mortality and economic loss. Viral pathogens are also causing serious threat, and Tilapia Lake Virus (TiLV) is a recently characterized globally distributed pathogen that has the potential to inflict devastating mortality events. These epidemic conditions are usually supported in intensive tilapia aquaculture systems, which are highly stocked, have poor water quality, and low biosecurity controls that facilitate quick transmission of the pathogens as a disease. The ensuing economic losses not only destabilize farmers' revenues but also threaten global tilapia supply chain stability (Chen et al., 2021). Development of disease-resistant tilapia lines is increasingly viewed as a cornerstone pillar of sustainable aquaculture. Vaccines and antibiotics will provide limited protection but are hindered by issues of antimicrobial resistance and expense, which restrict their long-term application. Selective breeding is a long-term and environmentally friendly solution by capitalizing on available natural genetic variation in disease resistance. Studies have shown moderate to high heritability for resistance to bacterial and viral infections, meaning that resistance may be enhanced with well-designed breeding schemes. Culturing of disease-resistant strains may reduce mortality, production costs, and increase farm overall resilience, thereby guaranteeing stable supply, food security, and sustainable world tilapia industry development.
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