# Two-Generation Genetic Evaluation of Female Reproductive Performance in Pacific White Shrimp (Penaeus vannamei) Under SPF Conditions

## TL;DR

This study shows that female Pacific white shrimp reproductive traits can be improved through selective breeding under controlled SPF conditions.

## Contribution

The first two-generational genetic analysis of female reproductive performance in Penaeus vannamei under SPF conditions.

## Key findings

- Female reproductive traits in P. vannamei are heritable and can be improved through selective breeding.
- Core reproductive traits showed low to moderate heritability and shared genetic control across generations.
- Strong positive genetic correlations suggest traits are genetically linked and can be improved together.

## Abstract

This study estimated genetic parameters for female reproductive traits in Penaeus vannamei under SPF (Specific Pathogen-Free) conditions across two consecutive generations, using a pedigree-based best linear unbiased prediction (pBLUP). The analyzed traits included spawning frequency (SF), mean spawning interval (MSI), number of eggs laid for the first time (NE1), average spawning (AS), total spawning (TS), and spawning success (SS). Our findings confirm that female reproductive traits in P. vannamei are heritable and can be effectively improved through selective breeding. Although heritability declined for some traits in the second year, core reproductive traits consistently exhibited low to moderate heritability and shared common genetic control. These results provide new insights into the feasibility of selecting for enhanced reproductive performance without compromising other economically important traits.

Reproductive inefficiency remains a major constraint in Penaeus vannamei hatcheries due to high rates of non-spawning females. This study presents the first two-generational quantitative genetic analysis of female reproductive performance under standardized SPF (Specific Pathogen-Free) conditions. A total of 986 females across two generations (2021–2022) from 198 full-sib and 68 half-sib families were evaluated. Traits analyzed included spawning frequency (SF), mean spawning interval (MSI), number of eggs laid for the first time (NE1), average spawning (AS), total spawning (TS), and spawning success (SS). Heritability estimates for SF, SS, and TS were moderate (0.30 ± 0.06, 0.23 ± 0.06 and 0.28 ± 0.07, respectively), while MSI, NE1, and AS showed low heritability (0.10–0.16). When analyzed separately by year, heritability estimates declined substantially for most traits in the second generation. Strong positive genetic correlations were observed between SF, MSI, NE1, AS, and TS, with pairwise estimates ranging from 0.82 to 0.99, indicating that these traits are under shared genetic control. Despite not being direct selection objects, all reproductive traits exhibited relative genetic progress (246–488% per generation), which is attributable to the high selection intensity applied to the parental generation. Our findings provide a robust foundation for integrating reproductive performance into breeding programs for P. vannamei, particularly under biosecurity and commercial feed-dominated conditions.