A Comparative Analysis of Muscle Nutritional Composition, Texture, Microstructure, and Metabolomics: Hybrid Sturgeon (Acipenser baerii Brandt ♀ × Acipenser schrenckii Brandt ♂) Versus Its Parent Varieties

The hybrid sturgeon (HS, Acipenser baerii Brandt ♀ × A. schrenckii Brandt ♂) was compared with its parental varieties (Siberian sturgeon (SS) and Amur sturgeon (AS)) to evaluate muscle quality differences. Three sturgeon species were bred from the same batch, reared under identical conditions until three years of age, and then male fish from each species (AS, 3.2 ± 0.18 kg; SS, 2.5 ± 0.14 kg; HS, 3.5 ± 0.21 kg) were sampled for analysis of muscle nutritional composition, texture, microstructure, and metabolomics. Results showed no significant differences in proximate composition, hydrolyzed amino acids, pH, or water-holding capacity among the three groups. However, HS exhibited higher gumminess and chewiness than both parent species, as well as greater hardness and springiness compared with the SS. Muscle fiber density was higher in HS than in the AS, but no significant difference was observed between HS and SS. Levels of free amino acids (Val, Ile, Ala) were lower in HS than in AS. In terms of fatty acid profiles, HS showed elevated polyunsaturated fatty acids compared with SS, resembling the pattern observed in AS. Muscle color of HS was similar to that of SS, whereas its a* value differed from those of AS. Metabolomics identified differential metabolites (GABA, D-glucosaminic acid, AP4) enriched in pathways such as ABC transporters, protein digestion and absorption, and amino acid metabolism. Overall, HS combines improved texture traits with meat quality attributes resembling SS (muscle color, free amino acids) and AS (polyunsaturated fatty acids). These characteristics suggest that HS possesses a distinctive combination of meat quality traits.