Enhancement of immunity and resistance of Vibrio alginolyticus in the white shrimp Litopenaeus vannamei that had received the Sargassum hemiphyllum var. chinense

• Main Authors: Huynh Truong Giang, 黃長江
• Other Authors: Jiann-Chu Chen
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/56169328181251830262

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 98 === To examine the induction of phenoloxidase (PO) activity and repiratory burst (RB) by the haemocytes of white shrimp Litopenaeus vannamei, the in vitro studies were conducted by treatments with Sargassum hemiphyllum var. chinense (SHC) powder and its hot-water extract. PO activity and RB were significantly enhanced in shrimp treated with the SHC extract. Induction of PO activity of haemocytes that elicited by the hot-water extract was significantly higher than that of laminarin. No significant difference in PO activity was observed between the hot-water extract and alginate. Superoxide anion was found indifferent among the hot-water extract, zymosan, laminarin, and alginate. Similarly, induction of phenoloxidase activity and superoxide anion significantly increased incubated with 3 mg ml-1 of SHC powder at size of 125 µm. White shrimp L. vannamei were immersed in aerated seawater containing SHC powder at 100, 300, 500, 1000, and 1500 mg L-1 or its hot water extract at 100, 300, and 500 mg L-1 were challenged with Vibrio alginolyticus at 8.0 × 105 or 9.2 × 105 colony-forming units (cfu) shrimp-1, followed by release in aerated seawater. Survival rates of shrimp that immersed in seawater containing SHC powder at 500~1500 mg L-1, and those of shrimp immersed in seawater containing the SHC extract at 300 and 500 mg L-1 were significantly higher than those of control shrimp after 48~120 h. In a separate experiment, the hyaline cell (HCs), granular cells (including semigranular cell, GCs) count, total haemocyte count (THC), haemocyanin, haemolymph protein, PO activity, RB, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, and lysozyme activity were measured when shrimp were immersed in seawater containing SHC powder at 100, 300, 500, 1000, and 1500 mg L-1 or the SHC extract at 100, 300, and 500 mg L-1. These parameters increased in a manner of dose-dependent and peaked at 3 h. Similarly, shrimp that received the SHC had significantly increased in phagocytic activities and clearance efficiencies at 1~5 h. It was concluded that innate immunity L. vannamei which received the SHC powder and its hot-water extract was enhanced and resistance against V. alginolyticus infection was also increased.