For externally fertilizing fishes, interactions between male and female gametes have been shown to have remarkable impacts on sperm performance. Ovarian fluid (OF) and its ability to alter the swimming behavior of fish sperm makes it a determining factor of fertility. With the expansion of channel catfish (Ictalurus punctatus) ♀ × blue catfish (Ictalurus furcatus) ♂ hybrid aquaculture, it is essential to understand the impacts during fertilization and the magnitude such gametic interactions have on sperm performance and subsequent male fertility potential. This study was conducted to address the following: 1) activate blue catfish sperm with/without channel catfish OF to determine impacts on sperm performance and 2) assess if sperm behave differently when activated in the OF from individual females. Sperm (n = 4 males) were activated without OF (control) and with diluted OF from unique females (n = 6), creating 24 experimental crosses. Sperm motility (%), velocity (VCL), and longevity were analyzed using computer assisted sperm analyses software. With OF incorporated in the activation media, sperm velocity was significantly higher than the control at 10, 20, and 30 s post-activation. OF did not have an impact on motility for any females at 10 s and 20 s post-activation but became significantly higher than the control at 30 s. In all cases, OF treatments greatly increased longevity. Male × female interactions were highly significant, such that motility, velocity, and longevity were dependent on specific male-female pairs. This information shows that OF should be incorporated in aquatic media to simulate natural spawning conditions and accurately assess the fluid mechanics of sperm propulsion for each male. Additionally, there are mechanisms that drive gamete interactions that need to be explored further, which may improve selection of male-female pairs for in-vitro fertilization. On a broad scale, our results also help to shed light on the complexities of fertilization and fish reproduction overall, which may have implications for recruitment variability and recovery strategies of threatened and/or endangered freshwater species.

中文翻译：

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鲶鱼卵巢液差异性地增强了蓝鲶鱼的精子性能

对于体外受精的鱼类，雄性和雌性配子之间的相互作用已被证明对精子性能有显着影响。卵巢液 (OF) 及其改变鱼精子游动行为的能力使其成为生育能力的决定性因素。随着沟鲶 (Ictalurus punctatus) ♀ × 蓝鲶 (Ictalurus furcatus) ♂ 杂交水产养殖的扩大，了解受精过程中的影响以及这种配子相互作用对精子性能和随后的雄性生育潜力的影响至关重要。本研究旨在解决以下问题：1) 在有/没有沟鲶 OF 的情况下激活蓝鲶鱼精子以确定对精子性能的影响，2) 评估精子在来自个体雌性的 OF 中激活时的行为是否不同。精子（n = 4 雄性）在没有 OF（对照）和稀释的来自独特雌性（n = 6）的 OF 的情况下被激活，产生 24 个实验杂交。使用计算机辅助精子分析软件分析精子活力 (%)、速度 (VCL) 和寿命。在激活介质中加入 OF 后，精子速度在激活后 10、20 和 30 秒显着高于对照。OF 在激活后 10 秒和 20 秒对任何雌性的运动性没有影响，但在 30 秒时显着高于对照。在所有情况下，OF 治疗大大延长了寿命。雄性×雌性相互作用非常显着，例如运动性、速度和寿命取决于特定的雄性-雌性配对。该信息表明，OF 应该被纳入水介质以模拟自然产卵条件并准确评估每个雄性精子推进的流体力学。此外，还有一些驱动配子相互作用的机制需要进一步探索，这可能会改善体外受精的雄性-雌性对的选择。在广泛的范围内，我们的结果还有助于阐明受精和鱼类繁殖的整体复杂性，这可能对受威胁和/或濒危淡水物种的补充变异性和恢复策略产生影响。