Sustainability of channel catfish, Ictalurus punctatus ♀ × blue catfish, Ictalurus furcatus ♂ hybrid aquaculture relies on new innovative technologies to maximize fry output. Transplanting spermatogonia from blue catfish into channel catfish hosts has the potential to greatly increase gamete availability, and cryopreservation would make these cells readily accessible year-round. However, a protocol for cryopreserving blue catfish testicular tissues has not yet been fully developed. Therefore, the objectives of this experiment were to identify the best permeating [dimethyl sulfoxide (DMSO), ethylene glycol (EG), glycerol, methanol] and non-permeating (lactose or trehalose with egg yolk or BSA) cryoprotectants, their optimal concentrations, and the best freezing rate (-0.5, -1.0, -5.0, -10 °C/min until -80 °C) that yields the highest number of live type A spermatogonia cells and highest viability percentages after cryopreservation. Results showed that all of these factors had significant impacts on post-thaw cell production and viability. DMSO was the most efficient permeating cryoprotectant at a concentration of 1.0 M. The optimal concentration of each cryoprotectant depended on the specific cryoprotectant due to interactions between the two factors. Of the non-permeating cryoprotectants, 0.2 M lactose with egg yolk further improved type A spermatogonia production and viability beyond that of the 1.0 M DMSO control. The overall best freezing rate was consistent at -1 °C/min, but similar results were obtained using -0.5 °C/min. Overall, we recommend cryopreserving blue catfish testicular tissues in 1.0 M DMSO with 0.2 M lactose and egg yolk at a rate of -1 °C/min to achieve the best cryopreservation outcomes. Continued development of cryopreservation protocols for blue catfish and other species will make spermatogonia available for xenogenic applications and genetic improvement programs.

中文翻译：

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蓝鲶鱼精原细胞冷冻保存方案的开发，Ictalurus furcatus

鲶鱼的可持续性，Ictalurus punctatus ♀ × 蓝鲶鱼，Ictalurus furcatus ♂ 杂交水产养殖依靠新的创新技术来最大限度地提高鱼苗产量。将蓝鲶鱼的精原细胞移植到沟鲶宿主体内有可能大大增加配子的可用性，而冷冻保存将使这些细胞全年都易于使用。然而，用于低温保存蓝鲶睾丸组织的协议尚未完全制定。因此，本实验的目的是确定最佳渗透性 [二甲亚砜 (DMSO)、乙二醇 (EG)、甘油、甲醇] 和非渗透性（乳糖或海藻糖与蛋黄或 BSA）冷冻保护剂，它们的最佳浓度，和最佳冷冻率 (-0.5, -1.0, -5.0, -10 °C/min 直到 -80 °C），在冷冻保存后产生最多数量的活 A 型精原细胞和最高的存活率。结果表明，所有这些因素对解冻后细胞的产生和活力都有显着影响。DMSO 是浓度为 1.0 M 时最有效的渗透冷冻保护剂。由于两个因素之间的相互作用，每种冷冻保护剂的最佳浓度取决于特定的冷冻保护剂。在非渗透性冷冻保护剂中，0.2 M 乳糖和蛋黄进一步提高了 A 型精原细胞的产生和活力，超过了 1.0 M DMSO 对照。总体最佳冷冻速率在 -1 °C/min 时保持一致，但使用 -0.5 °C/min 时获得了类似的结果。总体而言，我们建议在 1.0 M DMSO 中冷冻保存蓝鲶鱼睾丸组织，浓度为 0。2 M 乳糖和蛋黄以 -1 °C/分钟的速度加入，以达到最佳冷冻保存效果。蓝鲶和其他物种的冷冻保存方案的持续发展将使精原细胞可用于异种应用和遗传改良计划。