Effects of curcumin supplementation in high-fat diet on intestinal health of spotted sea bass (Lateolabrax maculatus)

This study examined the effects of curcumin (Cur) supplementation in high-fat diets on the intestinal antioxidant capacity, immunity, morphological structure, and microbial flora of spotted sea bass (Lateolabrax maculatus). Six experimental diets were formulated: a normal fat group (NF), a high-fat group (HF), and four HF groups supplemented with increasing concentrations of Cur (200, 400, 800, 1600 mg/kg Cur, referred to as Cur0.02, Cur0.04, Cur0.08, and Cur0.16, respectively). The experiment consists of 6 groups, each with 3 replicates, and each replicate contains 25 fish, with an average weight of approximately 2 +/- 0.16 g per fish. The culture system is maintained with continuous oxygenation, and the rearing period lasts for 10 weeks. The results indicated that The HF diet reduced the lipase (LPS) activity in the spotted sea bass, impaired the intestinal antioxidant and immune responses in the spotted sea bass, induced intestinal damage characterized by the shedding of villous tips and muscle layers; it also reduced the diversity of the intestinal microbiota. The results indicate that the addition of 400 mg/kg Cur increased the activity of LPS and trypsin (TRS) and significantly increased the total antioxidant capacity (T-AOC), alkaline phosphatase (AKP) activity, and lysozyme (LZM) activity in the intestines of spotted sea bass, while significantly reducing malondialdehyde (MDA) levels. This suggests an improvement in the intestinal antioxidant and immune functions. When 200 mg/kg Cur was added, improvements were observed in the intestinal muscle layer and the tip of the intestinal villi, along with an increase in the alpha-diversity of the intestinal microbiota and a higher relative abundance of Firmicutes and Bacteroidetes. In summary, the addition of 200-400 mg/kg Cur in a high-fat diet has a positive impact on the intestinal health of spotted sea bass.