Effect of melatonin and pinealectomy on gonadal activity during prespawning period of catfish (Heteropneustes fossilis)

ABSTRACT

Aim: The effects of intraperitoneal administration of melatonin dose (25, 50, 100, 200 and 400 mg per fish) on gonadal activities were evaluated during the prespawning period of catfish, Heteropneustes fossilis for 60 days. Methodology: In this experiment, fourteen aquariums were used because the experiment was performed in replicate and fifteen fishes were suspended in each glass aquarium. One group of male and female catfishes were considered as control group and the catfishes in the second group were pinealectomized whereas the remaining five treatments were administered with low (25, 50 mg per fish) and high (100, 200, 400 mg per fish) doses of melatonin. Results: During prespawning period of reproductive cycle, the gonado-somatic index of ovary of pinealectomized and melatonin treated fish decreased as compared to the control group. The number of yolky oocytes significantly decreased in the melatonin treated group as compared to the control group. After 60 days of pinealectomy, it showed inhibitory effects on the ovarian activity. The GSI of testes of pinealectomized fish decreased as compared to the control group. The number of spermatozoa cells increased with the increase in the melatonin dose as compared to control group. The GSI of testes was found maximum in the melatonin treated group as compared to the control group. Interpretation: This study supports the concept that melatonin hormone administration helps in maturation of testes and increases the number of spermatozoa. This was just contrary to the results obtained in female catfish where melatonin treatment showed inhibitory effects on the ovarian activity during prespawning period.