To compare the quality and nutritional differences of crayfish under freshwater and saline-alkali water aquaculture conditions, this study systematically analyzed the biochemical composition, physical properties, and nutritional evaluation of crayfish (Procambarus clarkii) cultivated in saline-alkali water (PC-SW) and freshwater aquaculture (PC-FW), respectively. The results showed that crayfish from PC-SW had higher crude protein, crude fat, water content, and ash content. At the same time, PC-SW had a higher meat yield (16.18 ± 0.74%) than PC-FW (p < 0.05), with no significant changes in the head weight ratio or hepatopancreas weight ratio, indicating superior crayfish quality. The trace element content of PC-SW differed significantly from that of PC-FW (p < 0.05), with the exception of Cu. To some extent, the amino acid and fatty acid compositions were similar. The no essential amino acids content of crayfish cultivated under freshwater and saline-alkali conditions was higher than the essential amino acids content. The total branched-chain amino acids (BCAAs) content was higher than the total aromatic amino acids (AACs) content in both groups; however, the BCAA to AAC ratio was similar, at approximately 2.14. The essential amino acid index results were 69.01 and 68.02, respectively. Finally, betaine and nucleotide concentrations increased and geosmin content was significantly reduced in PC-SW (3.13 ± 0.09 μg/kg) compared to PC-FW (4.32 ± 0.09 μg/kg) (p < 0.05), implying that PC-SW crayfish had a better flavor. Our findings revealed that cultivating crayfish under saline-alkali conditions can significantly improve the nutritional quality and flavor of muscle.

Saline and alkali aquaculture offers a sustainable strategy to alleviate pressure on freshwater resources and ecologically ameliorate saline and alkali environments; however, information regarding the quality of aquatic products from such conditions remains scarce. This study evaluated the nutritional components, color, texture, and flavor profiles of grass carp cultured under three representative saline and alkali conditions in China: carbonate (CB), chloride (CR), and sulfate (SF), with a freshwater-cultured grass carp (Ctenopharyngodon idellus) serving as a control (CK). The results obtained in our study showed that the CB group exhibited the lowest muscle water content (68.96 ± 0.04%). Crude fat and sodium levels were significantly elevated in all treatment groups compared to the CK group (p < 0.05). Conversely, the CK group displayed superior springiness and higher concentrations of geosmin, adenine, and uracil. Notably, the CR group exhibited the highest L* and whiteness values, whereas the CB and SF groups possessed significantly higher collagen content and enriched EPA and DHA levels. These findings demonstrate that saline and alkali conditions distinctly modulate the nutritional and flavor profiles of grass carp, highlighting their potential for producing value-added aquatic products under saline and alkali conditions.