Effects of dietary curcumin supplementation on growth performance, antioxidant capacity, and gene transcriptome in the juvenile Manila clam (Ruditapes philippinarum)

The complex conditions in aquaculture environments often lead to oxidative stress in juvenile bivalves, highlighting the need for effective mitigation strategies. This study evaluated the effects of dietary curcumin supplementation on growth performance, antioxidant capacity, and gene transcriptome in the juvenile clam ( Ruditapes philippinarum ). A total of 36 g of clams (individual body weight: 0.5 ± 0.17 mg, shell length: 1.15 ± 0.15 mm) were equally distributed into six groups (three replicates per group) and fed six microencapsulated diets containing 0, 50, 100, 200, 400, and 800 mg/kg of curcumin for three weeks. Results indicated that curcumin supplementation did not significantly influence growth performance. However, clams in the 200 mg/kg and 400 mg/kg groups exhibited markedly higher activities of catalase, superoxide dismutase (SOD), and glutathione, along with reduced malondialdehyde (MDA) levels compared to the 0 mg/kg group. Following treatment with hydrogen peroxide, the survival rate of clams in 400 mg/kg group was significantly higher than 0 mg/kg group. Meanwhile, the activities of SOD and Glutathione Peroxidase were significantly increased in the 400 mg/kg group, with a corresponding reduction in MDA levels compared to the 0 mg/kg group. The transcriptome analysis further revealed that supplementation with 400 mg/kg curcumin significantly upregulated the expression of genes related to autophagy and lysosomal pathways when compared to the 0 mg/kg group. In conclusion, our study suggested that supplementation with 400 mg/kg curcumin significantly enhanced the antioxidant capacity of clams, providing essential insights for mitigating oxidative stress in juvenile bivalve aquaculture. • The optimal curcumin supplementation level for juvenile clams was 400 mg/kg. • Curcumin increased antioxidant activity and decreased MDA levels in clam. • 400 mg/kg curcumin improved the survival of clam under H₂O₂-induced stress. • Compared to 0 mg/kg, 400 mg/kg curcumin significantly upregulated autophagy and lysosomal pathways in clam.