Laboratory of Cell Biology and Histology, Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria; Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Jos, Nigeria.
Laboratory of Cell Biology and Histology, Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria.
Anim Reprod Sci. 2024 Apr;263:107410. doi: 10.1016/j.anireprosci.2024.107410. Epub 2024 Jan 10.
The biological effects of simulated photoperiod and melatonin on the control of reproduction of guinea fowls (Numida meleagris) are not well understood. Herein, thirty (30) sexually mature guinea fowl cocks were randomly assigned to 1-6 groups (n = 5) and subjected to different photoperiodic regimes in the presence or absence of exogenous melatonin (Mel; 1 mg/kgBW/day, i/m) for eight weeks. Testes of the euthanized cocks were processed for gross morphology, histological, histochemical, and oxidative stress markers. Testosterone concentration was determined in serum samples using the enzyme-linked immunosorbent assay (ELISA) technique. We observed an increase in testicular size in the Mel and Non-Mel groups under long-day (LD) photoperiods, and in the Non-Mel group under short-day (SD) photoperiod. Conversely, the testicular size was drastically reduced in the Mel group for SD. Seminiferous tubules in the Mel and Non-Mel groups of the SD showed cytomorphological changes, including degenerated cells, focal vacuolations, and depletion of germinal epithelium. However, the germinal epithelium appeared to be complete and active in both the Mel and Non-Mel groups for the LD. In all groups, the testes showed positive staining for PAS with varying intensities. There was a significant difference in PAS-staining intensity between different photoperiodic regimes and exogenous melatonin. The study observed the interaction between photoperiods and exogenous melatonin on glutathione reductase (GSH), malondialdehyde (MDA), and serum testosterone. Overall, the results indicated that a long-day (LD) photoperiod, combined with exogenous melatonin, enhanced reproductive activity in male guinea fowl by increasing testicular size and serum testosterone concentration.
模拟光照周期和褪黑素对珍珠鸡繁殖控制的生物学影响尚不清楚。本研究将 30 只性成熟珍珠鸡公鸡随机分为 1-6 组（n=5），并在存在或不存在外源性褪黑素（Mel；1mg/kgBW/天，肌内注射）的情况下接受不同的光周期处理 8 周。处死公鸡后，对睾丸进行大体形态学、组织学、组织化学和氧化应激标志物检测。使用酶联免疫吸附试验（ELISA）技术测定血清样本中的睾酮浓度。我们观察到，在长光照周期下，Mel 和非 Mel 组的睾丸大小增加，而在短光照周期下，非 Mel 组的睾丸大小增加。相反，在短光照周期下，Mel 组的睾丸大小急剧减小。SD 组的 Mel 和非 Mel 组的精小管显示出细胞形态学变化，包括退化细胞、局灶性空泡化和生殖上皮耗竭。然而，在 LD 组，Mel 和非 Mel 组的生殖上皮似乎完整且活跃。所有组的睾丸均对 PAS 呈阳性染色，染色强度不同。不同光周期和外源性褪黑素之间的 PAS 染色强度存在显著差异。研究观察了光周期和外源性褪黑素对谷胱甘肽还原酶（GSH）、丙二醛（MDA）和血清睾酮的相互作用。总的来说，结果表明，长光照周期（LD）结合外源性褪黑素通过增加睾丸大小和血清睾酮浓度来增强雄性珍珠鸡的生殖活性。
