Analysis of Flesh Content, Muscle Nutritional Components and Quality of Crayfish Farmed in Paddy Fields in Major Breeding Provinces of China

Rice–crayfish co-culture is a dominant aquaculture mode in China, while the regional heterogeneity in crayfish nutritional quality remains insufficiently clarified. This study collected rice-field-cultured crayfish samples from six major producing provinces (Henan, Hubei, Hunan, Jiangxi, Jiangsu, and Anhui) to systematically evaluate their meat yield, conventional nutritional components, amino acid and fatty acid profiles, and mineral element contents. Significant regional differences were observed in all measured indicators. Jiangsu crayfish showed the highest meat yield (22.97% in females, 20.72% in males), crude protein (18.5%), and total amino acids (16.59 g/100 g). Jiangxi samples had the highest crude fat (0.7%), ash (1.5%), and calcium (1280 mg/kg). Anhui crayfish exhibited the highest polyunsaturated fatty acid (PUFA) content (47.30%). Hubei recorded the highest total eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) (22.41%). Henan crayfish were highest in EPA (19.6%) and manganese (3.72 mg/kg), while Hunan samples had the highest iron (9.06 mg/kg). Valine was identified as the first limiting amino acid in all provinces, with secondary limiting amino acids varying regionally. Despite regional differences in specific nutritional indices, crayfish from all six provinces consistently exhibited high protein, low fat, balanced amino acid profiles, abundant unsaturated fatty acids, and rich essential minerals, with all measured nutritional mineral contents within national food safety limits. The findings provided empirical data and a scientific basis for crayfish quality evaluation, origin characteristic analysis, and targeted nutritional optimization of farming formulas, as well as for the differentiated development of regional crayfish industries.