Effect of LED light quality on respiratory metabolism and activities of related enzymes of Haliotis discus hannai

摘要

Oxygen consumption and ammonia excretion rates of abalone (Haliotis discus hannai) of differing sizes (wet weight 63.74 +/- 8.49 g, 17.49 +/- 3.20 g, and 3.52 +/- 0.94 g) were evaluated under five different light emitting diode (LED) conditions (red, orange, purple, green, and blue light) and in dark and natural light environments. The weight-specific oxygen consumption/ammonia excretion rates decreased significantly with increasing body weight, and these relationships could be expressed by the exponential equations R = aW(b) and E = aW(b) (P 0.05), respectively. The oxygen consumption/ammonia excretion rates of abalone in the red light, orange light, and dark environment treatments were lower than those in the green, blue, natural, and purple light treatments, and the highest rates (3.27 mg g(-1) h(-1)/187 mu g g(-1) h(-1)) occurred in the purple light treatment (P 0.05). The O/N ratio exceeded 10 in all light quality groups, indicating that the energy requirements were met by carbohydrate and fat. In another experiment, the effects of different light qualities on the activities of hexokinase (HK), pyruvate kinase (PK), superoxide dismutase (SOD), and catalase (CAT) in juvenile abalone (wet weight 17.49 +/- 3.20 g) were investigated at 0.5, 1, 3, 6, 12, 24, and 72 h of light exposure. HK and PK activities in the green, purple, blue, and natural light groups were significantly higher than those in the red light, orange light, and dark environment (P 0.05). SOD activity increased immediately when the abalones were placed in green, purple, blue, and natural light, then decreased gradually and returned to its original level. CAT activity did not increase until 12 h and was higher in the green, purple, blue, and natural light groups than in the red light, orange light, and dark environment (P 0.05). These results suggest that more carbohydrates were provided and utilized by the glycolytic cycle when the abalones were exposed to adverse light conditions. Therefore, the selection of appropriate light conditions (red and orange light) and the control of metabolic waste ammonia will have a significant impact on high-intensity aquaculture in recirculating cultivation systems.