Hypoxia has become a significant issue both in open aquatic environment and closed aquaculture system. Development of hypoxia-tolerant breeds is one of the practical strategies in further fish farming. In present study, the hybrid Pelteobagrus fulvidraco (PF) × Leiocassis longirostris (LL) was generated by artificial insemination. Both PF ♀ × LL ♂ and LL ♀ × PF ♂ could produce F₁ offspring, assigned as hybrid PL and hybrid LP, respectively. The hybrid PL exhibited higher hatching rate, expectant morphological traits, and an improved trait on hypoxia-tolerance compared to hybrid LP. However, the growth trait was not strengthened at early development stage until 90 dpf compared to hybrid LP and LL. To further examine the hypoxia-tolerant machinery of the hybrid PL strain, we systematically investigated the tissues morphology, hypoxia inducible factor (HIF)-related genes expression, and oxidative stress enzymes activity of gill, liver, and intestine under acute hypoxia and reoxygenation. The histological results showed that the interlamellar cell mass was expanded in the gill, obvious vacuolation and swell of hepatocytes was found in the liver, and expanded submucosa was observed in the intestine, suggesting the tissues remodeling was evidenced in hybrid PL responding to hypoxia. A rapid HIF-related genes response (Hif-1α, Hif-2α, Vhl, Fih-1, Phd3, and Vegf-a) and activation of anti-oxidant enzymes activity (T-SOD, CAT, and GPx) among three tissues were patently illustrated. Our results indicated that the complex combination of morphological, molecular, and biochemical adjustments might contribute jointly to the hypoxia-tolerance of hybrid PL. This study provided an alternative and possible method for hypoxia-tolerant fish strain generation using hybridization breeding in aquaculture.

缺氧已成为开放水环境和封闭水产养殖系统的重要问题。开发耐缺氧品种是进一步养鱼的实际策略之一。在本研究中，通过人工授精产生了杂交黄颡鱼(PF) ×  Leiocassis longirostris (LL)。PF ♀ × LL ♂ 和 LL ♀ × PF ♂ 都可以产生 F ₁后代，分别指定为混合 PL 和混合 LP。与杂交 LP 相比，杂交 PL 表现出更高的孵化率、预期的形态特征和改进的耐缺氧性状。然而，与杂交 LP 和 LL 相比，直到 90 dpf 的早期发育阶段，生长性状才得到加强。为了进一步研究杂种 PL 菌株的耐缺氧机制，我们系统地研究了急性缺氧和复氧条件下鳃、肝脏和肠道的组织形态、缺氧诱导因子 (HIF) 相关基因表达和氧化应激酶活性。组织学结果显示，鳃内层间细胞团扩大，肝内可见明显的空泡化和肿胀，肠内可见黏膜下层扩大，表明组织重塑在响应缺氧的混合PL中得到证实。快速的 HIF 相关基因反应（Hif-1α、Hif-2α、Vhl、Fih-1、Phd3和Vegf -a ) 以及三种组织中抗氧化酶活性 (T-SOD、CAT 和 GPx) 的激活得到了明确的说明。我们的研究结果表明，形态、分子和生化调整的复杂组合可能共同促进杂种 PL 的耐缺氧性。本研究为在水产养殖中使用杂交育种产生耐缺氧鱼品系提供了一种替代和可能的方法。