DIETARY VITAMIN A REQUIREMENT OF JUVENILE RED SWAMP CRAYFISH (<italic>PROCAMBARUS CLARKII</italic>)

This study aimed to investigate the effects of dietary vitamin A and determine its requirement of juvenile red swamp crayfish (Procambarus clarkii). Six isonitrogenous, isolipidic, and isoenergetic experimental diets were formulated with analyzed vitamin A potencies of 11573 (A1), 20042 (A2), 26274 (A3), 37818 (A4), 55159 (A5), and 79200 (A6) IU/kg, respectively. These diets were fed to crayfish with an initial average body weight of (3.40±0.01) g for 8 weeks. The results revealed that weight gain rate and specific growth rate were significantly higher in groups A4 and A5 compared to the control group (A1) (PPPPChitinase, EcR, and RXR in the hepatopancreas, while significantly down-regulating the expression of MIH (PP. clarkii. Based on broken-line regression analysis of weight gain rate, specific growth rate, and feed conversion ratio, the recommended dietary vitamin A requirement for juvenile Procambarus clarkii is 37976—43443 IU/kg.