The regulative effect of Urtica dioica on sex hormones imbalance: elevated follicle-stimulating hormone/luteinizing hormone ratio ≥4.5 is associated with low performance in aged breeder quails

The age-related reproductive disorders are the main concerns in old birds. It was suggested that a drop in egg production and reproductive performance, towards the end of their laying period was caused partly by a decrease in the baseline concentration of plasma LH. Urtica dioica (nettle) is a plant with natural aromatase inhibitors. Steroid hormone levels are regulated by inhibition of the aromatase enzyme. Few studies have examined the effect of nettle on the egg production in adult hens. The aim of this study was to investigate the effects of diet supplemented with nettle powder (NP) in aged quails. One hundred and forty-52-week-old Japanese quails were randomly assigned to four treatments consisting of seven replicates (n = 5; four females and one male) and fed with diets containing NP at 0% (control group), 0.5, 1.0, and 1.5% (treatment groups). At 62 week of age, our results indicated the NP improved egg production, feed conversion ratio, eggshell thickness and Haugh unit (p < .05). Notably, fertility and hatchability of fertile eggs were significantly increased, while total embryonic mortality decreased significantly by supplementing diet with nettle powder (p < .05). Higher luteinizing hormone, lower oestrogen, malondialdehyde and total cholesterol and triglyceride concentrations were associated with percent of the nettle powder in diet (p <= .05). Elevated follicle-stimulating hormone/luteinizing hormone ratio >= 4 is associated with low egg production in control group and nettle supplementation can balance FSH/LH ratio to <= 2.7. It is concluded that nettle powder could be used as a worthwhile feed additive at the late laying period of aged quails.