Iron is an important mineral for animal development and function. The present study was carried out to evaluate the effect of FeSO₄ replacement with cysteine-coated Fe₃O₄ nanoparticles in quail. We hypothesised that the iron nanoparticles could be used as a dietary supplement. The quails were randomly allotted to five dietary treatments with four replicate pens and 10 birds per pen. The treatments consisted of: negative control without any iron supplementation, positive control with 120 mg/kg of FeSO₄ and three experimental groups that contained 1.2, 12 and 120 mg/kg of l-cysteine coated iron oxide nanoparticles, organic iron, in their diet, respectively. The least weight gain was recorded in the negative control group. Similar weight gain, FCR, haematological and biochemical parameter results between the experimental and positive control groups show that organic iron successfully performed the biological role of iron in the quail. We concluded that 1.2 mg/kg cysteine-coated Fe₃O₄ nanoparticles are required and sufficient for quails’ optimal maintenance and growth. The results confirm that cysteine-coated Fe₃O₄ nanoparticles can be used as an iron source in the quail diet.

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.