An account of oxidative stress, antioxidant response and glucose concentration due to artificial photoperiodic regimes in Koi (Cyprinus carpio var koi)

Abstract

Artificial photoperiodic configurations are preferred over natural environment to accelerate growth and development in fishes. However, these artificial photoperiodic exposures might exert an unwanted physiological stress to the fish. The present work used juvenile Koi to evaluate Lipid Peroxidation (LPO) indicating Oxidative damage, Antioxidant response (Glutathione-S-Transferase – GST, Glutathione – GSH and Catalase – CAT) and Glucose (GLU) concentrations to two artificial photoperiodic regimes. The effect of Light (L) and Dark (D) photoperiod (18L:06D and 10L:14D) was investigated in gill and white muscle after a period of 30 days relative to the natural photoperiod (Control ≈ 12L:12D). Compared to the control, LPO was found to be significantly reduced (p < 0.01) for 18L:06D in gill and significantly increased (p < 0.001) for 10L:14D in muscle. A considerable elevation was observed for Catalase (p < 0.001) in muscle and reduction (p < 0.05) in gill for 10L:14D. GST did not have any significant impact on gill, rather a significant increase (p < 0.001) and decrease (p < 0.01) was observed for muscle in 18L:06D and 10L:14D, respectively. GSH increased significantly in gill for 10L:14D (p < 0.05). Glucose concentration surged in gill and muscle for both the photoperiodic arrangements (p < 0.01; p < 0.001). Distinctively, exposure to short light duration 10L:14D had greater impacts in both the tissues for most of the variables assessed. The results of this study can be useful in strategizing an ambient photoperiodic regime intended for upregulating growth and development in economically important fishes like Koi.