Effect of melatonin supplementation on gonadotropins, Vitellogenin gene expression, antioxidant status, ovarian histology and reproductive performance in female Clarias magur

This study investigates the effects of melatonin supplementation on gonadotropin gene expression, vitellogenin (Vtg) gene expression, antioxidant status, ovarian histology, and reproductive performance in female Clarias magur . Four experimental diets were formulated: control (0 mg/kg melatonin), T1 (100 mg/kg melatonin), T2 (200 mg/kg melatonin), and T3 (300 mg/kg melatonin). Results showed no significant difference in weight gain between the control and T1 groups, while weight gain decreased notably in T2 and T3. Gonadosomatic index (GSI) and fecundity were monitored over a 60-day feeding trial. The T1 group exhibited significantly higher GSI and fecundity compared to the control, whereas T2 and T3 groups showed significant reductions in both parameters. Histological evaluation revealed more atretic eggs in T3, while T1 contained mature and primary/secondary yolk stage (PYS/SYS) oocytes. Gonadotropin and vitellogenin gene expression in Clarias magur was evaluated from April to June, with samples collected at three time points: April (I sampling, before the start of the feeding trial), May (II sampling, after one month of the feeding trial), and June (III sampling, at the end of the feeding trial).Gonadotropin gene expression (FSH and LH) was significantly affected by melatonin. FSH gene expression peaked at the II sampling in the T1 group, while it was lowest in T3. LH gene expression peaked at the III sampling in the T1 group, showing a marked reduction in higher melatonin doses (T2 and T3 group). Vtg gene expression increased in the T1, reaching the highest levels at the II sampling, while it was inhibited in the T3 group. Antioxidant enzymes (SOD, CAT, GPX, GST) varied significantly with melatonin doses. Lower melatonin doses (T1) reduced antioxidant enzyme activity, while higher doses (T3) enhanced it. Induced breeding outcomes demonstrated that melatonin at 100 mg/kg significantly improved fertilization, hatching, larval survival, and fry survival, outperforming the control group. Our findings indicate that melatonin supplementation at 100 mg/kg enhances reproductive performance in Clarias magur by modulating ovarian development, gonadotropin gene expression, oxidative stress, and improving survival rates in the early life stages.