Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7090, Uppsala, 750 07, Sweden.
Department of Medical Biochemistry and Microbiology, Genetics and genomics, Uppsala University, Uppsala, Sweden.
BMC Genomics. 2023 Sep 4;24(1):519. doi: 10.1186/s12864-023-09614-9.
Substantial variation in male fertility is regularly observed in farmed Arctic charr. However, detailed investigations of its fluctuation during a reproductive season and across years are lacking. Furthermore, information about the effect of underlying genetic factors influencing sperm quality is scarce. The current study focused on seasonal and age-related factors that may affect sperm quality characteristics in males reared in natural and delayed photoperiods. Animals were sampled three times for two consecutive years, and sperm quality parameters were recorded using a computer-assisted sperm analysis (CASA) system. Thereafter, high-throughput sequencing technologies were applied, aiming to identify genomic regions related to the variation of sperm quality throughout the reproductive season.
An across-season variation in the recorded sperm quality parameters was evident. Overall, 29% and 42% of males from the natural and delayed spawning groups had a highly variable total progressive motility. Males at four years of age showed significantly higher sperm motility and velocities during the early October and November recordings compared to the following year when the same animals were five years of age. On the other hand, the opposite was observed regarding sperm concentration during the last sampling. A genome-wide F scan detected SNP differentiation among males with high and low variability in total progressive motility (PM) on eight chromosomes (F > 0.17), Genome wide windows with the highest F contained SNPs in proximity (within 250 kb up- and downstream distance) to 16 genes with sperm quality biological functions in mammalian species.
Our findings provide a detailed view of seasonal, age-related, and genetic effects on sperm quality and can be used to guide decisions on broodstock selection and hatchery management.
在养殖的北极红点鲑中，雄性生育力存在显著的变异性。然而，对于其在繁殖季节和多年间波动的详细调查仍然缺乏。此外，关于影响精子质量的潜在遗传因素的信息也很有限。本研究专注于季节性和年龄相关因素，这些因素可能会影响在自然和延迟光照条件下饲养的雄性的精子质量特征。在连续两年中，动物被三次采样，使用计算机辅助精子分析（CASA）系统记录精子质量参数。随后，应用高通量测序技术，旨在鉴定与整个繁殖季节精子质量变化相关的基因组区域。
记录的精子质量参数存在跨季节变化。总体而言，自然产卵组和延迟产卵组中分别有 29%和 42%的雄性具有高度可变的总前向运动性。四岁的雄性在 10 月和 11 月初的记录中表现出显著更高的精子活力和速度，而同年五岁的同一批雄性则表现出较低的精子活力和速度。另一方面，在最后一次采样时，精子浓度则相反。全基因组 F 扫描检测到在具有高和低总前向运动性（PM）变异性的雄性之间的 SNP 分化（F > 0.17），包含具有精子质量生物学功能的 16 个基因的 SNP 位于基因组宽窗口中，这些基因位于哺乳动物物种中 PM 高度可变的雄性附近（上下游距离 250kb 以内）。
我们的研究结果提供了关于精子质量的季节性、年龄相关和遗传效应的详细信息，可以用于指导亲鱼选择和孵化场管理的决策。
