Evaluating the effects of dietary resistant starch on growth, digestion, metabolism, immunity and resistance to ammonia stress in Litopenaeus vannamei

摘要

Resistant starch (RS) is considered to be a good alternative to antibiotics. A 56-day feeding trial was followed by induction of acute ammonia stress to evaluate the effects of dietary RS on growth, digestion, metabolism, immunity and resistance to ammonia stress in Litopenaeus vannamei. The four diets used differed only in RS content: 0 g/kg (Control), 10 g/kg (RS1), 30 g/kg (RS2) and 50 g/kg (RS3). The results showed that dietary RS improved the growth and the survival rates of shrimp exposed to ammonia stress. At 56 days, the activity of digestive and metabolic enzymes (amylase, lipase, pepsin, hexokinase and pyruvate kinase) was increased in the three RS groups, while trypsin activity only increased in the RS1 and RS2 groups; immune-related parameters (the total antioxidant capacity; the activity of superoxide dismutase, total nitric oxide synthase and phenoloxidase; and the expression of heat-shock protein 70, thioredoxin, prophenoloxidase, lysozyme and toll gene) were increased in the three RS groups. After exposure to ammonia stress, all the selected immune parameters of the three RS groups were higher than those of the control group at 24 hr. Therefore, dietary RS improved the growth, digestion, metabolism, immunity and resistance to ammonia stress in L. vannamei.