Comparative Analysis of Flesh Quality in Triploid and Allotetraploid Pengze Crucian Carp: Nutritional Composition, Flavor Profile, Texture Properties, and Metabolomics Insights

This study provides a systematic and multidimensional evaluation of flesh quality differences between triploid (T-PZ) and allotetraploid (A-PZ) Pengze crucian carp, addressing a significant gap in genetic improvement of this economically important aquaculture species. By integrating proximate composition analysis, detailed amino acid and fatty acid profiling, volatile flavor compounds, texture characteristics, and non-targeted muscle metabolomics, we delineated the distinct quality attributes associated with each cytotype. The results showed that T-PZ possessed significantly higher crude protein and histidine content, along with a superior flavor profile characterized by lower relative levels of fishy odor-associated aldehydes such as hexanal, heptanal, and nonanal. In contrast, A-PZ exhibited significantly elevated crude lipid, total fatty acid, SFA, MUFA, PUFA, and EPA + DHA contents; a higher essential amino acid index; and improved tenderness indicated by significantly lower hardness and chewiness. Metabolomic analysis identified 216 significantly different metabolites, notably enriched in key pathways including glycine, serine, and threonine metabolism; arginine biosynthesis; and glycerophospholipid metabolism. These comprehensive findings elucidate the complementary nutritional and sensory strengths of the two ploidy forms, thereby establishing a crucial scientific foundation for targeted, quality-driven breeding programs aimed at optimizing flesh quality in Pengze crucian carp for the aquaculture industry.