Effects of dietary phospholipid and cholesterol levels on antioxidant capacity, nonspecial immune response and intestinal microflora of juvenile female crayfish, Procambarus clarkii

Abstract

The current study is conducted to evaluate the interactive effects of different phospholipids (PL) and cholesterol (CH) levels on the immune response and intestinal microbiota of juvenile female red swamp crayfish, Procambarus clarkii. A total of 270 healthy crayfish with an average initial weight of 5.92 ± 0.03 g were fed nine semi-purified diets containing three different levels of PL (0, 20 and 60 g/kg of diet) and CH (0, 5 and 10 g/kg of diet, as a 3 × 3 experiment design) for 60 days. The superoxide dismutase (SOD) activity in serum was enhanced by dietary supplementation of PL and CH (P < 0.05), and the activity of alkaline phosphatase (AKP) and phosphatase (ACP) decreased significantly with increasing dietary PL levels (P < 0.05). There was a significant interaction between PL and CH on malondialdehyde (MDA) content, catallase (CAT), total antioxidant capacity (T-AOC) and glutathione peroxidase (GPx) activities (P < 0.05). Optimal dietary PL and CH levels could significantly improve the abundance of intestinal microflora, change and optimize the intestinal flora composition and decrease pathogenic bacteria relative abundance. When CH addition level at 5 g/kg, the Bacteroidetes abundance was the highest and the relative abundance of Candidatus Bacilloplasma was the lowest compared with the other groups (P < 0.05). Considering antioxidant capacity, nonspecial immune response and microbial community structure, the optimal PL and CH requirements were estimated to be 60 g/kg and 5 g/kg for juvenile female P. clarkii, respectively.