The immunostimulatory effects of hot-water extract of Gelidium amansii via immersion, injection and dietary administrations on white shrimp Litopenaeus vannamei and its resistance against Vibrio alginolyticus

• Published in: Fish & Shellfish Immunology Vol. 22; no. 6; pp. 673 - 685
• Main Authors: Fu, Yu-Win, Hou, Wen-Ying, Yeh, Su-Tuen, Li, Chiu-Hsia, Chen, Jiann-Chu
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2007
• Subjects: Adjuvants, Immunologic - administration & dosage; Adjuvants, Immunologic - pharmacology; Administration, Oral; Animals; Diet; Diet - veterinary; Gelidium amansii; Hot Temperature; Hot-water extract of Gelidium amansii; Immersion; Immune parameter; Immunity, Innate - drug effects; Injection; Injections - veterinary; Litopenaeus vannamei; Marine; Monophenol Monooxygenase - metabolism; Penaeidae - drug effects; Penaeidae - enzymology; Penaeidae - immunology; Penaeidae - microbiology; Phagocytosis - drug effects; Resistance; Respiratory Burst - drug effects; Rhodophyta - chemistry; Seawater; Superoxide Dismutase - metabolism; Survival Analysis; Vibrio alginolyticus; Vibrio alginolyticus - immunology; Water - chemistry; Resistance; Hot-water extract of Gelidium amansii; Diet; Litopenaeus vannamei; Vibrio alginolyticus; Immersion; Injection; Immune parameter
• ISSN: 1050-4648; 1095-9947; 1365-2567
• DOI: 10.1016/j.fsi.2006.08.014

The total haemocyte count (THC), phenoloxidase activity, and respiratory burst were examined when white shrimp Litopenaeus vannamei were immersed in seawater (34‰) containing hot-water extract of red alga Gelidium amansii at 200, 400 and 600 mg l −1, injected with hot-water extract at 4 and 6 μg g −1 shrimp, and fed diets containing hot-water extract at 0, 0.5, 1.0 and 2.0 g kg −1. These parameters increased significantly when shrimp were immersed in seawater containing hot-water extract at 400 and 600 mg l −1 after 1 h, when shrimp were injected with hot-water extract at 6 μg g −1 shrimp after one day, and when shrimp were fed diets containing hot-water extract at 1.0 and 2.0 g kg −1 after 14 days. Phagocytic activity and clearance efficiency were significantly higher for the shrimp that were fed diets containing hot-water extract at 1.0 and 2.0 g kg −1 than those of shrimp that were fed diets containing hot-water extract at 0 and 0.5 g kg −1 after 14 and 28 days. In a separate experiment, L. vannamei which had received hot-water extract via injection, or fed diets containing hot-water extract, were challenged after 3 h or 28 days with V. alginolyticus at 2 × 10 6 cfu shrimp −1 and 1 × 10 6 cfu shrimp −1, respectively, and then placed in seawater. The survival of shrimp that were injected with hot-water extract at 6 μg g −1 was significantly higher than that of control shrimp after 1 day, and the survival of shrimp fed diets containing hot-water extract at 0.5, 1.0 and 2.0 g kg −1 increased significantly after 3 days as well as at the end of the experiment (6 days after the challenge), respectively. It was concluded that L. vannamei that were immersed in hot-water extract at 400 mg l −1, injected with hot-water extract at 6 μg g −1 shrimp, and fed hot-water extract of G. amansii at 2.0 g kg −1 or less showed increased immune ability as well as resistance to V. alginolyticus infection.