Growth Performance and Transcriptome Profiles of the Hybrid Between Hungarian and Vietnamese Common Carp (Cyprinus carpio)

The Vietnam Hungarian hybrid carp has been used as broodstock in several selective breeding programs; however, its underlying transcriptomic mechanisms remain poorly understood. In this study, pure Vietnamese carp (V) were crossed with pure Hungarian carp (H) and growth performance was evaluated after one year of culture. The greatest heterosis was observed in the V♀×H♂ cross (VH) compared with the reciprocal cross (H♀ × V♂, HV) and pure Vietnamese carp (VV). To elucidate the molecular basis of this hybrid vigor, high-throughput RNA-Seq was performed on liver and muscle tissues from fast- and slow-growing individuals within VH hybrids. A total of 28 differentially expressed genes (DEGs) were identified, including 11 upregulated and 17 downregulated in fast-growing fish. Gene Ontology enrichment analysis showed that the upregulated DEGs were mainly associated with growth related processes, whereas the downregulated DEGs were primarily involved in cell polarity and immune responses. Notably, fast-growing VH hybrids exhibited a stronger genetic influence from Hungarian carp, as reflected in both morphological traits and gene expression patterns. Overall, these findings provide novel insights into the molecular regulation of growth in hybrid common carp and highlight the potential of selective breeding strategies to improve growth performance in common carp.