Effect of GnRH administration on egg production, hormonal and biochemical profile and ovarian histomorphology of spent naked neck layers

This study evaluated the effects of GnRH administration on egg production, hormonal and biochemical profile and ovarian histomorphology in spent Naked Neck layers. A total of 150 seventy-two-week-old Naked Neck spent layers were assigned to three treatment groups: a control receiving physiological saline (DL0), GnRH administration every three days (DL1), and GnRH administration every seven days (DL2). Egg production significantly increased (P < 0.001) in GnRH-treated groups from week two onward, with DL2 showing the highest production (52.38% at day 42) compared to DL1 (45.71%) and DL0 (15.23%). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels significantly increased (P < 0.001) in GnRH-treated groups. By day 42, FSH levels reached 2.649 IU/ml in DL2, followed by 1.959 IU/ml in DL1, while the control remained at 1.450 IU/ml. Similarly, LH levels peaked at 0.792 IU/ml in DL2, significantly higher than DL1 (0.627 IU/ml) and DL0 (0.355 IU/ml). Ovarian histomorphology revealed significant follicular development in GnRH-treated groups. Overall, GnRH administration improved reproductive performance in spent layers, with weekly injections (DL2) demonstrating the most pronounced effects on egg production and hormonal profiles.