COMPARATION ON MUSCLE FLAVOUR QUALITY AND METABOLOMICS OF PENGZE CRUCIAN CARP (CARASSIUS AURATUS VAR. PENGZE) UNDER POND AND LAND-BASED ROUND POND CULTURE MODES

This study aimed to analyze and compare the differences in muscle flavor quality of Pengze crucian carp (<italic>Carassius auratus</italic> var. Pengze) under pond culture and land-based round pond culture modes, and preliminarily investigated the underlying mechanisms using metabolomics. The results showed that compared to the land-based round pond group, the pond culture environment exhibited significantly lower total phosphorus, ammonia nitrogen, and total nitrogen (<italic>P</italic>&lt;0.05) but significantly higher dissolved oxygen (<italic>P</italic>&lt;0.05). The relative content of polyunsaturated fatty acids (PUFAs), particularly linoleic acid, in the muscle was significantly higher in pond-cultured fish (<italic>P</italic>&lt;0.05), while the relative content of monounsaturated fatty acids (MUFAs), especially oleic acid, was significantly lower (<italic>P</italic>&lt;0.05). The umami substances inosine monophosphate (IMP) and guanosine monophosphate (GMP) were both present at higher levels, but no significant intergroup differences were observed (<italic>P</italic>&gt;0.05). GC-MS analysis identified 141 volatile substances in the muscle from both culture modes, with 14 differential volatile substances identified as characteristic flavor markers based on abundance. Among these, 10 substances were significantly upregulated in the land-based round pond group (<italic>P</italic>&lt;0.05), including creamy and fruity aroma compounds as well as high-sensory-threshold acidic off-flavor substances. The overall abundance of volatile substances in the land-based round pond group was significantly higher than that in the pond group (<italic>P</italic>&lt;0.05), accompanied by significantly elevated electronic nose sensor responses. These data suggest that land-based round pond culture may promote the accumulation or synthesis of volatile substances in Pengze crucian carp muscle. Metabolomics analysis revealed 312 differential metabolites between the two groups, with 181 upregulated and 131 downregulated in land-based round pond-cultured fish compared to pond-cultured fish, providing more flavor precursors. KEGG pathway enrichment analysis highlighted steroid hormone biosynthesis and arachidonic acid metabolism as the primary differential metabolic pathways. These findings demonstrate that various environmental factors influence muscle fatty acid composition and metabolites deposition through pathways such as arachidonic acid metabolism and steroid hormone biosynthesis, thereby inducing the formation of differential volatile flavor compounds in fish from the two culture modes.