Abstract
This study was designed to examine the immunoregulatory effects of alginate-derived oligosaccharides (ADOs) on farm-cultured Pacific white shrimp Penaeus vannamei and its resistance to Vibrio harveyi. Total hemocyte count, superoxide dismutase (SOD) activity, bacteriolytic activity, phagocytic rate (PR), the average number of beads ingested per cell (ABPC), and the protective efficacy for P. vannamei challenged with Vibrio harveyi were determined. The study showed that the administration of ADOs at 1.0 g/kg of diet improved SOD activity, bacteriolytic activity, and PR by 25.2, 20.4, and 20.9%, respectively, 30 d after exposure. Total hemocyte count and ABPC showed no significant differences. The 96-h survival of the shrimp reached 46.7% and 90.0% when they were challenged with V. harveyi at concentrations of 1 × 107 and 1 × 106 cfu/shrimp, which was significantly higher than that in the control group. The results obtained indicate that ADOs can act as an immunoregulant for P. vannamei.
Received February 11, 2017; accepted July 29, 2017Published online September 18, 2017
Acknowledgments
This work was supported by the Qingdao Science and Technology Project (16-4-2-5-nsh).