The black tiger shrimp (Penaeus monodon) industry in Thailand faced severe setbacks between 2000–2004 due to slow growth, disease outbreaks, poor seed quality, and unfavorable culture conditions. These challenges led farmers to shift to Pacific white shrimp (Litopenaeus vannamei) in 2005 onwards . However, P. monodon remains highly valuable in the premium international market due to its larger size and higher profit margins per kilogram.
To reintroduce high-quality P. monodon to farmers, government agencies, including NSTDA, and private companies have worked extensively on selective breeding programs to enhance growth rates and disease resistance. Over the past decade, our research team has focused on developing triploid (3n) shrimp via chromosome manipulation through cold shock induction. These 3n shrimp exhibit 1.5–2 times faster growth compared to diploid (2n) shrimp, with energy redirected towards growth due to reproductive deficiencies in both males and females. Ongoing research aims to optimize the commercial viability of 3n shrimp farming by developing automated tools for egg collection and cold shock processing.
In the present study, we investigated the immune system of triploid shrimp to enhance their health and resilience. We examined the hemato -immunological parameters of 3n shrimp, including total hemocyte count (THC), differential hemocyte count (DHC), hemocyte size, phenoloxidase (PO) activity, O₂⁻ production, alkaline phosphatase (ALP), peroxinectin (PXN), lysozyme, and immune gene expression (ppae1 and crus ). The study results demonstrated that triploidy significantly affects THC, with a 40.37% decrease, alters DHC (with a reduction in hyaline cells by 11.3–15.9% and an increase in large-granular cells by 15.1–33.5%), and results in larger hemocytes. PO and ALP activities were elevated, while stimulated O₂⁻ production was higher in triploids. Additionally, ppae1 and crus gene expressions in the gills and hemolymph were significantly upregulated.
These findings highlight that triploid P. monodon not only achieves faster growth but also possesses a robust immune defense system, making it a promising candidate for sustainable aquaculture practices.