Dietary supplementation with thyme oil improves the reproductive characteristics of Barki adult and prepubertal ewes

The reproductive technology has a significant impact on the development of livestock production. The thyme oil, rich in phytoestrogen chemicals like apigenin, has been found to enhance reproductive performance by mimicking estrogen's action. This study aimed to investigate the effects of oral supplementation with thyme essential oil on the reproductive organ biometry, and reproductive performance in adult and prepubertal Barki ewes. Seventy ewes were treated with intravaginal sponges impregnated with 40 mg. medroxyprogesterone acetate for 14 days and simultaneously assigned randomly to two groups (20 adult and 15 prepubertal ewes per group), i.e., a control and a thyme oil treated (2.25 mg/kg body weight) group. The number of follicles, follicle diameter, corpora lutea diameter, and estrogen concentration were higher in the thyme oil-treated group than in the control group without comparing between adult ewes and prepubertal ewes. Additionally, the number and diameter of the large follicles were higher (P < 0.05) in the right-side ovary of adult ewes compared with that in prepubertal ewes at day 15. Moreover, thyme oil treatment resulted in higher conception (P < 0.01), lambing rates (P < 0.05), and fecundity (P < 0.01), with values 95.12, 136.73, and 130.25 compared with those in the control group, with values 63.51, 105.24, and 66.97, respectively, without comparing between adult ewes and prepubertal ewes. The adult ewes had a stronger estrus response and better fertility measurement values than prepubertal ewes. Additionally, the estrogen serum levels were positively correlated with the number (P < 0.05) and diameter (P < 0.01) of follicles, and the progesterone serum concentration was positively correlated with the corpora lutea diameter (P < 0.01), without treated group. In conclusion, dietary supplementation with thyme oil improved the follicular population and reproductive performance, which has a good effect on the adult and prepubertal ewes in the Barki ewes.