전자저널 > 전자저널 > Effect of cold stress on nitric oxide concentration in blood cockle (Tegillarca granosa)

Effect of cold stress on nitric oxide concentration in blood cockle (Tegillarca granosa)

Hee-Jung Lee, Jae-Hee Song, Hee-Do Jeung and Kyungil Park

South East Sea Fisheries Research Institute, NIFS, Tongyeong 39769, Korea Tidal Flat Research Institute, NFIS, Gunsan 54014, Korea Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, Gunsan 54150, Ko

Winter mortality of blood cockles (Tegillarca granosa) is one of the main concerns of cockle aquaculture in Korea. Thus, we investigated the physiological alternation of cockles when they were placed in abnormally cold temperatures. For this purpose, cockles were exposed to temperatures of 4°C (control), 2°C, 0°C, –2°C, and –5°C for four hours/day over eight days, and the condition index, nitric oxide concentration, and mortality rates were measured after each cold treatment. The results showed that the cockle nitrite concentration increased significantly in all groups, except for the control group, from the 1st day of exposure, and that this NO increase continued until the end of the experiment. In addition, cockles exposed to –5°C for 5 days showed an increase mortality rate. These results suggested that cockles experienced physiological stress when they were exposed to < 2°C, and might have resulted in mortality under severe hypothermic conditions in winter. Our study also suggested that the measured NO concentration in the hemocytes of cockles is an efficient biomarker for diagnosing physiological stress in cockles exposed to cold shock.

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