研究了促黄体生成素释放激素类似物(LHRH-A)不同处理方式对雄性赤点石斑鱼性类固醇激素分泌和精子生成及精子排放的影响.对照组在0、7 d二次注射生理盐水(50 μg?kg-1BW),注射组在0、7 d二次注射LHRH-A(50 μg?kg-1 BW),埋植组在0 d埋植LHRH-A缓释剂(100 μg?kg-1BW).结果表明,通过埋植LHRH-A缓释剂,血清睾酮(T)和11-酮基睾酮(11-KT)水平快速增加,显示血清睾酮和11-酮基睾酮水平与赤点石斑鱼精子生成和精子排放有密切关系.组织学观察表明,在21 d,对照组和注射组鱼精巢充满了精子细胞、精母细胞和精原细胞,而在同一时间,LHRH-A埋植组鱼精巢含有大量精子,表明精子排放仍在进行.在40 d期间采集精液总量为对照组＜注射组＜埋植组,差异显著.当注射组在处理14 d后精液量逐渐回落到对照组水平时,埋植组仍然维持较高精液量水平.各组采集的精子的活力与采集的精液量呈正相关,而精子密度没有显著差异.数据显示,LHRH-A缓释剂能显著增加赤点石斑鱼的精液量及延长精子排放时间而不改变精子的质量.

This study examined the effects of different mode of administration of LHRH-A on spermiation in the red spotted grouper （ Epinephelus akaara ）. Groups of red spotted grouper received either saline injection on 0, 7 day （ C, 50μg?kg^-1 body weight [BW] ） or LHRH-A injection on 0, 7 day（ IN, 50μg?kg^-1 body weight [BW] ） or a slower-releasing implant（ IM, 100μg? kg^-1 body weight [BW] ）. Serum levels of the androgens testosterone （T） and 11-ketotestosteron （11-KT） were significantly affected by the sustained LHRH-A delivery systems, serum T and 11-KT levels increased rapidly after being implanted. These results indicated a close correlation between sustained stimulation of T and 11-KT release, achieved by LHRH-A delivery systems, and long-term enhancement of milt production. Histological evaluation of the testes indicated that, by day 21, control and injection fish testes contained almost exclusively spermatozoa. At the same time, testes from LHRH-A implanted fish still contained large numbers of spermatozoa in the testes, indicating that spermiation was still underway. Over 40 days experimental period a total of milt volume as follows ： controls 〈 injection 〈 implantation. LHRH-A treatments stimulated a significant increase in total milt volume. While milt volumes in injected males returned to control values by day 14, implanting treated with sustained LHRH-A delivery systems maintained significantly elevated milt volumes for 40 days. Sperm motility tended to be positively correlated with milt volume, and there were no significant differences in sperm counts. These data show that sustained administration of LHRH-A significantly increases and prolongs spermiation in the red-spotted grouper without altering sperm concentration or quality.

国家高技术研究发展计划(863计划)，国家自然科学基金，广东省科技厅科技计划，教育部科学技术研究项目