The effects of dietary curcumin on growth, antioxidant, transcriptome, and metabolomics in Macrobrachium rosenbergii fed a high plant-protein diet

Insufficient attention has been directed towards the effects of incorporating curcumin (CU) into high plant-protein feeds and the underlying mechanisms at play. This study aims to evaluate the physiological responses of Macrobrachium rosenbergii to varying levels of CU in diets with high soy protein concentrate (SPC), examining factors such as growth characteristics, proximate composition, antioxidant capacity, immunity, histopathology, transcriptome, and metabolomics. Dietary formulations included a fishmeal-based diet (R), a high plant-protein diet (C, with 60 % fishmeal replaced by SPC), and C diets supplemented with CU at different concentrations: CU1 (1 g/kg), CU5 (5 g/kg), and CU10 (10 g/kg). Compared to R diet, the C diet did not significantly alter growth, proximate composition, antioxidant defense, or immune parameters of M. rosenbergii. However, the CU10 diet significantly improved final body weight (FBW), weight gain, and specific growth rate (SGR). Prawns in the CU10 group demonstrated the highest crude lipid content, succeeded by those in the C and CU5 groups, while the CU1 group had the lowest lipid content. Additionally, the CU10 diet reduced hemolymph malondialdehyde (MDA) levels and increased intestinal mucosal thickness significantly. Transcriptome analysis of the hepatopancreas revealed nine significantly expression genes across treatments. Metabolomics of the hepatopancreas identified three significantly expression metabolites across treatments: gemigliptin, artonol A, and lucuminoside. Moreover, the substitution of SPC and the addition of CU regulated ‘glycerophospholipid metabolism’ through their effects on the gene-metabolite regulatory network. In summary, a 10 g/kg CU supplementation in a high plant-protein diet notably augmented growth characteristics, enhanced antioxidant capacity, and improved hepatopancreas and intestinal health, while also refining transcriptome and metabolomics profiles.