Administration of hot-water extract of Padina boergesenii via immersion route to enhance haemolymph-immune responses of Fenneropenaeus indicus (Edwards)

Abstract

Various polysaccharides extract from marine algae to increase the non-specific immune system in crustacean. In this study, effects of hot-water extract on total haemocyte count, total plasma protein, Phagocytic activity, bacterial clearance efficiency and bactericidal activity while the shrimp Fenneropenaeus indicus (10.12±2.18 g) were immersed in seawater (40 g L−1 and 25±0.8 °C) containing hot-water extract of brown algae Padina boergesenii at 100, 300 and 500 mg L−1 for 1–4 h, were investigated. These parameters increased significantly (P<0.05) when the shrimp were immersed in seawater containing hot-water extract at 100 mg L−1 after 3 h and 300 and 500 mg L−1 after 2 h. Fenneropenaeus indicus that were immersed in hot-water extract at 300 and 500 mg L−1 had significantly increased phagocytic activity and increased clearance efficiency to Vibrio harveyi after 2 h. But bactericidal activity increased after 1 h immersed in 500 mg L−1 concentration.