The effects of four dietary lipid sources (fish oil, peanut oil, soybean oil, pork lard) on growth and gonad maturation of pre‐adult female red claw crayfish, Cherax quadricarinatus, were evaluated. Performance was evaluated by weight gain, specific growth rate (SGR), survival, feed conversion ratio (FCR), gonadosomatic index (GSI), fatty acid composition, and vitellogenin (vg) gene expression. The proportion of saturated fatty acids (SFA), mono‐unsaturated fatty acids (MUFA), and poly‐unsaturated fatty acids (PUFA) in hepatopancreas varied as a result of lipid source, while differences in muscle were limited to MUFA levels. Vg expression and growth, but not GSI, differed significantly, with peak expression and optimal growth observed in red claws receiving the soybean oil diet. Conversely, diets high in EPA (20:5n3) and DHA (22:6n3) produced suboptimal results, suggesting that the importance of maturation diets with high EPA and DHA content may be exaggerated. As the dietary lipid requirements of growing and reproductively active red claw crayfish were satisfied by a plant oil that contained high levels of 18‐carbon unsaturated fatty acids, soybean oil may be an economic alternative to the expensive lipid‐fortified feed currently utilized by the aquaculture industry.

Redclaw cray¢sh (Cherax quadricarinatus) females at di¡erent stages of vitellogenesis were sampled to investigate variations in soluble protein, lipid and water content and in the amino acid and fatty acid composition of the hepatopancreas and ovaries. During vitellogenesis, the changes in the content of soluble proteins and lipids in the hepatopancreas and ovaries were dependent on both diet and the reserves from the hepatopancreas. However, in comparison to the ovary, the £uctuation of the amino acid composition in the hepatopancreas suggested that the protein resources mobilized from this organ was compensating for those gained from feeding. Changes in the fatty acid composition of the hepatopancreas showed limited compensatory function as for the quick accumulation of lipids in the ovaries. The proportional amounts of saturated fatty acids/mono-unsaturated fatty acids/poly-unsaturated fatty acids (PUFA) and the predominant fatty acids in both tissues indicated that the mobilization and utilization of fatty acids in freshwater species are di¡erent from that in marine species. Based on the redclaw's feeding habits, the commercial pellets used in this study may not be optimal, and a diet with less PUFA may su⁄ce for its vitellogenesis and reduce the feeding costs.