Amino acid and fatty acid analyses in muscles and hepatopancreas of red crayfish at different growth stages

Abstract:

This study investigated changes in fatty acid and amino acid contents in the muscle and hepatopancreas of red crayfish (Cherax quadricarinatus) at different growth stages, i.e., before the second sex development (90 days), at maturation of second sex (140 days), and at gonadal maturity (180 days). Sixteen types of amino acids in the muscle were found, and the content of essential amino acids (EAAs) at 90 days was significantly higher than the other two periods (P<0.05). However, the content of EAAs and non-essential amino acids in the hepatopancreas of crayfish decreased gradually. Among fatty acids, the saturated fatty acids (SFA) in the muscle showed a decreasing trend; the monounsaturated fatty acid (MUFA) content first increased and then decreased, reaching peak content of (25.69±0.42%)% at 140 days, whereas the polyunsaturated fatty acid (PUFA) content increased from 90 to 180 days. Furthermore, the SFA content in the hepatopancreas showed no significant difference among the three growth periods (P>0.05); the MUFA content first increased and then decreased, peaking (37.44±0.59)% at 140 days, while the PUFA content showed the opposite trend. Moreover, the evaluation of nutritional value revealed that the EAA index (49.96%) of the muscle of 180-day-old (marketable) red crayfish was higher than the FAO/WHO score model (31.50%) and the whole egg protein model (43.10%), which is considered an ideal source of high-quality protein. In conclusion, the consumption of amino acids and fatty acids in the muscle and hepatopancreas is different. These results provide a theoretical reference for understanding the nutritional requirements of red crawfish at different stages of growth and development.