The immune responses of orange-spotted grouper Epinephelus coioides and its susceptibility to Vibrio alginolyticus under thermal and salinity stresses

• Main Authors: Shao-An Cheng, 鄭紹安
• Other Authors: Jiann-Chu Chen
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/97784870821168241914

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 96 === Orange-spotted grouper Epinephelus coioides held in 34? seawater were then cultured onward at 6?, 20? and 34? (control), and were examined for non-specific cellular and humoral responses after 3, 6, 12, 24, 48 and 96 h. Total leucocyte count increased significantly when fish were transferred to 20? after 3~48 h, but decreased significantly when fish were transferred to 6? after 3~96 h. Concerning the non-specific cellular response, respiratory burst increased significantly when fish were transferred to 20? over 3~96 h, phgaocytic rate increased significantly when fish were transferred to 20? after 3~24 h. However, respiratory burst and phagocytic rate decreased significantly when fish were transferred to 6? after 3~96 h. Concerning the non-specific humoral response, lysozyme activity and alternative complement pathway (ACH50) decreased significantly when fish were transferred to 20? and 6? after 3~96 h. E. coioides that received Vibrio alginolyticus at 2.3 × 109 colony-forming units (cfu) fish-1 and then placed in seawater of 34?, 20? and 6? was examined for mortality. Survived of fish that transferred to 6? seawater was significantly lower than that of fish that transferred to 34? and 20? over 48~120 h. It was concluded that E. coicoides subjected to salinity change from 34? to low salinity (6?) decreased its immunity and its resistance against V. alginolyticus. E. coioides held in 27 ℃ seawater were then cultured onward at 19 ℃, 27 ℃ (control) and 35 ℃, and were examined for non-specific cellular and humoral responses at 12, 24, 48 and 96 h. Total leucocyte count decreased significantly when fish were transferred to 19 ℃ after 48 to 96 h, and when fish were transferred to 35 ℃ after 24~96 h. Concerning the non-specific cellular response, respiratory burst decreased significantly when fish were transferred to 19 ℃ and 35 ℃ over 48~96 h, and phagocytic rate decreased significantly when fish were transferred to 19 ℃, and 35 ℃ over 24~96 h. Concerning the non-specific humoral response, lysozyme activity and alternative complement pathway (ACH50) decreased significantly when fish were transferred to 19 ℃ and 35 ℃ after 48~96 h. E. coioides that received V. alginolyticus at 2.3 × 109 cfu fish-1 and then placed in seawater of 19 ℃, 27 ℃ and 35 ℃ was examined for mortality. Survival of fish that transferred to 19 ℃ and 35 ℃ was significantly lower than that in the control temperature (27 ℃) after 24~120 h. It was concluded that E. coioides subjected to temperature change from 27 ℃ to low temperature (19 ℃) and high temperature (35 ℃) decreased its immunity and its resistance against V. alginolyticus.