为探讨otx2基因在七彩神仙鱼(Symphysodon haraldi)亲代抚育过程中的作用,本试验采用RT-PCR法克隆得到了七彩神仙鱼otx2基因,otx2基因的cDNA序列的CDS区序列长度为873 bp,共编码290个氨基酸,预测分子质量为31771.55 Da,理论等电点为9.40.运用SMART、Swiss-model和MEGA软件对基因的结构及物种进化关系进行分析.氨基酸序列预测显示,该基因具有otx保守结构域,在进化关系上与尼罗罗非鱼和白边锯鳞鱼亲缘关系相近,同源性分析发现,其氨基酸序列与尼罗罗非鱼、长鮣、西瓜刨、牙鲆和白边锯鳞鱼的同源性都在75％以上.荧光定量PCR分析显示,otx2基因在雌性七彩神仙鱼的脑、心脏、肝脏、肾脏等组织中都有表达,并且在脑组织中显著高表达.荧光原位杂交结果显示,otx2基因在七彩神仙鱼脑组织中的小球周灰质带、纵枕、顶盖室等区域均有表达.

Parental care is common in mammals and allows offspring to obtain milk, a substance rich in a range of nutritional and non-nutritional factors crucial to the survival of newborns. The discus fish Symphysodon spp., an Amazonian cichlid, shows an unusual behaviour: Free-swimming fry bite on their parents' skin mucus for growth and development during the first month after hatching. This is similar to the breastfeeding behaviour of mammals, but little is known about the regulatory mechanism by which discus secrete 'milk' and the related genes involved in parental care. Here, transcriptome sequencing was performed by using the brain tissues of female discus fish in parental and non-parental care. The results showed that a total of 86 differentially expressed genes (71 up-regulated genes and 15 down-regulated genes) were obtained by comparing parental with non-parental discus fish, including up-regulated LAPTM, FOXB, SOX1S, OTX2 and NR1F2, and down-regulated EDNRB, PRKCD, H1-5 and HBE. Through functional enrichment analysis, a total of 20 pathways were identified, e.g., estrogen signaling pathway, inflammatory mediator regulation of TRP channels, vascular smooth muscle contraction, GnRH signaling pathway, neurotrophin signaling pathway, NOD-like receptor signaling pathway, Jak-STAT signaling pathway, Fc gamma R-mediated phagocytosis, serotonergic synapse, autophagy-animal and cytokine-cytokine receptor interaction. These pathways and related genes might play important roles in the regulation of discus 'milk' secretion.

野生兰州鲶,又名兰州鲇,俗称鲶鱼.体长,头较为扁平,体后部侧扁,口裂末端与眼前缘相对,上下颌各有一对胡须,性成熟野生兰州鲶卵为灰绿色半黏性卵.其为肉食性鱼类,常栖息于河流缓流处或静水中,系底层鱼类,有避光趋暗的习性,多在黄昏或夜间活动觅食,分布于黄河水系,5月～6月份繁殖.兰州鲶肉质细嫩、味美,是鱼类的上品,兰州鲶肉具有催乳等药用价值,主治水肿、乳汁不足等.

为提高西北地区鲟鱼养殖过程中发眼卵的成活率,本研究于2018年从北京水产研究所引进鲟鱼卵,在甘肃省渔业技术推广总站所属甘肃省鱼类良种试验站用地下盐碱水进行鲟鱼发眼卵的孵化培育试验.结果表明,地下盐碱水的碱度和盐度对鲟鱼发眼卵的孵化影响较大,鲟鱼发眼卵在碱度为1.5～3.5 mmol/L、盐度为6‰～8‰、最适温度为20.5℃的水质条件下孵化率可达80.25％.地下盐碱水的碱度具有较高的生产力,盐度降低了鲟鱼发眼卵孵化过程中水霉的繁殖速率,减少了水霉对鲟鱼发眼卵孵化的水质破坏,从而增加了鲟鱼发眼卵的孵化率.