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The present study was conducted to determine the effects of dietary phosphorus (P) levels on growth performance, body composition, liver histology and enzymatic activity, and expression of lipid metabolism-related genes in spotted seabass (Lateolabrax maculatus). Seven diets were prepared to contain available P levels of 0.48% (the control group), 0.69%, 0.89%, 1.10%, 1.28%, 1.51% and 1.77% and feed fish (4.26 ± 0.03 g) to satiety twice daily for 10 weeks. Significantly higher weight gain and specific growth rate were recorded at P levels of 0.69%–1.51% compared to the control group. Feed conversion ratio decreased with increasing P levels up to 0.89% and increased thereafter. The lowest liver lipid content, viscerosomatic index and lipid content of whole-body were obtained in the 0.89%-P group among dietary treatments. P and calcium (Ca) contents in whole body were increased, while liver triglyceride and cholesterol contents were decreased with increasing dietary P levels from 0.48% to 1.77%. The highest activity of hepatic lipase was recorded in the 1.10%-P group among dietary treatments. Compared to the control group, 1.10% P enhanced the proportion of HUFA and reduced the proportion of SFA and MUFA. The histological observations showed that P deficiency (0.48%) led to the vacuolization of hepatocytes and increased number of lipid droplets. Meanwhile, overall liver tissue structure was improved when P level increased to 1.28%. Compared to the control group, expression of lipid metabolism-related genes such as FAS, ACC-2 and SREBP-1 was decreased at 0.89%–1.10% P group while an opposite trend was observed in the expression of PPARa2 and CPT-1 genes. The current study showed that 0.89% dietary P levels could promote growth performance of spotted seabass and reduce lipid accumulation in the liver. A broken-line regression analysis based on weight gain showed that the optimum dietary P level (available P) for juvenile spotted seabass reared in freshwater was 0.72%.