Effects of LED light quality on the growth, metabolism, and energy budgets of Haliotis discus discus

In this study, a bioenergetics approach was used to examine the effects of different LED light qualities (red, orange, blue, green light, natural light and a dark setting) on the growth and survival of the abalone Haliotis discus discus, and its physiological response mechanism under different light qualities. The results suggest that under blue or green light, the survival rate, specific growth rate, food intake, and food conversion efficiency of H. d. discus were significantly lower than in those groups under red or orange light (P < 0.05). Under red or orange light, pepsin, amylase and cellulose activity was significantly higher than those in any other light quality group (P < 0.05), whereas lipase activity exhibited no significant difference among the light quality groups (P > 0.05). Under blue or green light, lactate dehydrogenase activity and lactic acid content were higher (P < 0.05), suggesting enhanced anaerobic metabolism. Under blue or green light, H. d. discus lost more energy via excretion, feces and respiration than was acquired from its food. Under red or orange light, H. d. discus acquired more energy from its food and lost less energy via excretion and feces; as a result, its assimilation efficiency (K1) and net growth efficiency (K2) were significantly higher than those of any other group (P < 0.05). Therefore, we suggest that red or orange light should be used as a light source for the aquaculture of H. d. discus.