Zupa R, Fauvel C, Mylonas C C, Pousis C, Santamaria N, Papadaki Μ, Fakriadis I, Cicirelli V, Mangano S, Passantino L, Lacalandra G M, Corriero Aldo
J Anim Sci. 2017 Sep;95(9):4085-4100. doi: 10.2527/jas2017.1708.
The greater amberjack, (Risso, 1810), is a promising candidate for the diversification of European aquaculture production, but inconsistent reproduction in captivity prevents commercial production. Recent studies showed that greater amberjack confined in sea cages exhibited scarce gonad development and early interruption of gametogenic activity during the reproductive season. The aim of the present study was to improve our understanding of the observed impairment of spermatogenesis. Adult wild and captive-reared males were sampled during 3 different phases of the reproductive cycle: early gametogenesis (EARLY; late April to early May), advanced gametogenesis (ADVANCED; late May to early June), and spawning (SPAWNING; late June to July). Spermatogonial stem cells and proliferating germ cells were identified through the immunohistochemical localization of and proliferating cell nuclear antigen, respectively. Apoptotic germ cells were identified throughout the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling method. Sperm quality of captive-reared fish was evaluated using computer-assisted sperm analysis. Captive-reared males exhibited seminiferous lobules of a smaller diameter, a precocious and progressive decrease of spermatogonial mitosis, and a high level of apoptosis at the beginning of the reproductive season, concomitant with a many-fold higher 17β-estradiol plasma concentration. The motile spermatozoa percentage of captive greater amberjack was lower than in other teleosts, and a drastic decrease of spermatozoa motility duration, velocity, and ATP content occurred along the reproductive season. An abnormal increase of sperm concentration as well as an increase of dead spermatozoa occurred during the SPAWNING phase, probably because of lack of sperm hydration and ejaculation and consequent sperm ageing. The present study demonstrates the extreme susceptibility of greater amberjack to rearing stress and underscores the need for improvement of the rearing and handling procedures to ameliorate gametogenesis dysfunctions in commercial aquaculture production.
大琥珀鱼(Risso,1810)是欧洲水产养殖生产多样化的一个有前景的候选品种,但圈养繁殖的不一致性阻碍了商业生产。最近的研究表明,圈养在海笼中的大琥珀鱼在繁殖季节性腺发育稀少,配子发生活动提前中断。本研究的目的是加深我们对观察到的精子发生受损情况的理解。在繁殖周期的3个不同阶段对成年野生和圈养雄性进行采样:配子发生早期(EARLY;4月下旬至5月初)、配子发生后期(ADVANCED;5月下旬至6月初)和产卵期(SPAWNING;6月下旬至7月)。分别通过增殖细胞核抗原的免疫组织化学定位鉴定精原干细胞和增殖生殖细胞。通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法鉴定凋亡生殖细胞。使用计算机辅助精子分析评估圈养鱼类的精子质量。圈养雄性的生精小叶直径较小,精原细胞有丝分裂早熟且逐渐减少,在繁殖季节开始时凋亡水平较高,同时血浆17β-雌二醇浓度高出许多倍。圈养大琥珀鱼的活动精子百分比低于其他硬骨鱼,并且在整个繁殖季节精子活力持续时间、速度和ATP含量急剧下降。在产卵期精子浓度异常增加以及死精子数量增加,可能是由于缺乏精子水化和射精以及随之而来的精子老化。本研究表明大琥珀鱼对养殖应激极度敏感,并强调需要改进养殖和处理程序,以改善商业水产养殖生产中的配子发生功能障碍。