EFFECT OF MELATONIN ON THE PHYSIOLOGICAL COLOUR CHANGE IN THE BLINDED FISH, CLARIAS BATRACHUSPallavi Sahu, Chandrahasini Nirnejak, Naresh Chandra Agrawal, Saman SiddiquiAbstract The photo neuroendocrine system of the teleost fishes known to regulate rapid aggregation and dispersion of melanosomes within the chromatophores. The present study, throws light on the melatonin effect on the physiological color change in experimentally blinded fish, Clarias batrachus. In this experiment, the blinded fish after acclimation were divided into two groups namely experimental group containing blinded fishes and control group containing fishes with intact eyes. The cryptic response observed in scales of experimental and control groups at different time intervals i.e., 00, 05, 10, 20, 30 and 60 minutes after their recovery from the effects of anesthesia (Tricaine). The result was microscopically analysed, showing significant dispersion and contraction of melanosomes in fish skin, which changed to dark colour during dispersion and again reversed to lighter shade due to contraction. Experimentally blinded fish failed to respond to changes in its body color in relation to its backgrounds. After melatonin injection fish stated paling within 5 min. and remained so for 20 min. after that they acquired complete dark shade within an hour. It is concluded that both pineal and extra-pineal melatonin hormones perform different physiological processes. |