The impact of melatonin administration on the fertility performance and several relating parameters during the breeding season in the Arabi ewes

Abstract

randomly into four groups (6 animals for each group). The first group included the non-treated control group, while the other three groups were subjected to various oral doses of melatonin 9 mg, 12 mg and 15 mg/head, respectively. All treatments were applied at 6 o’clock in the morning, to investigate the effect of treatment with melatonin during breeding season on reproductive performance and levels of some biochemical parameters in Arabi ewes from 1 May to 1 October 2017. Blood samples 7ml were collected after one hour of treatment and then monthly during the pregnancy months to determine the concentrations of biochemical parameters. After Postpartum, lambed ewes/lambs number, birth weight, placenta empty weight and cotyledon number were recorded. The results showed significant (P<0.05) improvement in reproductive performance (fertility percentage, twinning rate and the number of offspring) when ewes administrated melatonin at two doses (12 and 15 mg/ head). Also, melatonin administration caused significant (P<0.05) decrease in the concentrations of thyroxin, cortisol, and cholesterol. Conversely, there was a significant increase (P<0.05) in glucose concentration after 1 hour of treatment. The concentrations of thyroxin, cortisol, cholesterol, and vitamin C increased significantly (P<0.01) in early-gestation compared with mid and late-gestation, while the concentrations progesterone and glucose increased significantly (P<0.05) in midgestation compared with early and late-gestation. In conclusion, melatonin administration at doses 12 and 15 mg/ head improves ewe reproductive performance (fertility percentage, twinning rate and the number of born lambs). Additionally, the gestation stage has a negative effect on the concentrations of thyroxin, cholesterol and vitamin C.