Dietary curcumin influence on growth, antioxidant status, immunity, gut flora and resistance to Vibrio harveyi AP37 in Haliotis discus hannai

Abstract

Curcumin (CUR), as a natural and innocuous phytogenic compounds, is regarded as a multifunctional feed additive with growth-promoting and immunostimulant potential in aquaculture. The effects of dietary CUR on the survival and growth of the abalone (Haliotis discus hannai) were evaluated by measuring growth, hematological parameters, and the abundance and diversity of gut flora. A total of 720 abalones (shell length: 59.69 ± 0.15 mm, body weight: 24.80 ± 0.20 g) were randomly distributed into six group (six replicates each group), fed six diets containing 0, 0.05, 0.1, 0.2, 0.4, and 0.8 g/kg of CUR for 100 days. Results indicated that CUR supplementation at 0.1–0.4 g/kg diet improved the growth performance. When the addition of CUR was greater than 0.1 g/kg, the activities of catalase, superoxide dismutase, glutathione peroxidase and total antioxidant capacity in the serum and hepatopancreas were significantly increased, while the contents of malondialdehyde were significantly reduced (P < 0.05). After infection with Vibrio harveyi AP37, the survival rate in all CUR supplementation groups were significantly higher than the control group (P < 0.05), and the highest values of the total hemocyte count, reactive oxygen species, and phagocytic activity were recorded in CUR 0.1 group. In addition, supplementation of the diet with 0.1 g/kg CUR decreased the gut microbial diversity indices and increased the abundance of potentially beneficial genera including Mycoplasma (26.82%), Psychrilyobacter (23.62%) and Vibrio (21.44%). In conclusion, addition of 0.1 g/kg of CUR to the diet not only improved the survival, growth, feed utilization, and regulated gut flora composition of abalone, but also effectively enhanced their antioxidant capacity, cellular immunity and resistance to V. harveyi AP37 infection. Therefore, CUR may be a useful feed additive for abalone aquaculture.

Keywords

• Dietary additives
• Abalone
• Antioxidant
• Cellular immunity
• Disease challenge test
• Gut microflora