White shrimp Litopenaeus vannamei that have received Petealonia binghamiae extract activate immunity, increase immune response and resistance against Vibrio alginolyticus

Abstract

This study was to examine immune response of white shrimp Litopenaeus vannamei and its resistance against Vibrio alginolyticus when shrimp received Petalonia binghamiae extract in vitro and in vivo. Shrimp hemocytes incubated with 1 mg/ml extract showed increased Phenoloxidase (PO) activity and respiratory burst (RB, release of superoxide anion). The total hemocyte count (THC), Phenoloxidase (PO) activity, respiratory Burst (RB) of shrimp received the extract at 6 and 10 µg/g were significantly higher than those of shrimp received saline and the control shrimp after 48, 96 and 144 h. Superoxide Dismutase (SOD) activity of shrimp received the extract at 6 and 10 µg/g were significantly higher than those of shrimp received saline and the control shrimp after 48 h. Phagocytic activity and clearance efficiency to Vibrio alginolyticus in the shrimp that received the extract at 6 and 10 µg/g were significantly higher than those of shrimp received saline and the control shrimp after 24, 48, 96 and 144 h. In another experiment, shrimp which had received the extract at 2, 6, and 10 µg/g after one day were challenged with V. alginolyticus at 1.4×106 colony-forming units (cfu)/shrimp, and then placed in seawater. The survival rate of shrimp that received the extract at 6 and 10 µg/g was significantly higher than that of control shrimp after 12-144 h. It was concluded that P. binghamiae extract could cause activation of shrimp immunity, and concluded that shrimp received the extract at 6~10 µg/g increased immune response of shrimp as well as resistance to V. alginolyticus infection.