Examination of survival, physiological parameters and immune response in relation to the thermo-resistant heterosis of hybrid oysters derived from Crassostrea gigas and C. angulata

• Published in: Aquaculture 2022-10, Vol.559, p.738454, Article 738454
• Main Authors: Jiang, Gaowei, Zhou, Jianmin, Cheng, Geng, Meng, Lingxin, Chi, Yong, Xu, Chengxun, Li, Qi
• Format: Article
• Language: English
• Subjects: C. angulata; Crassostrea gigas; Enzymatic activities; Heterosis in heat-resistance; Oxygen consumption
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2022.738454

High temperature is an important environmental stressor leading to summer mass mortality of oysters. Significant survival heterosis in summer were observed in hybrids between two phylogenetically closely-related oysters, Crassostrea gigas and C. angulata, but an explicit understanding of heterosis has been lacking. Here, we investigated the survival performance, oxygen consumption rate (OR) and enzyme activity (i.e., SOD, CAT and MDA) in C. gigas (GG), C. angulata (AA) and their hybrids C. gigas ♀ × C. angulata ♂ (GA) and C. angulata ♀ × C. gigas ♂ (AG) under acute heat stress containing five levels: 22, 26, 30, 34 and 38 °C. Compared with parental strains, the hybrid strains exhibited higher cumulative survival rate at all temperatures, indicating heterosis for thermal tolerance. Cox regression analysis showed that hybrid strains challenged with heat shock exhibited lower hazard ratio and longer expected lifetime. Moreover, OR in hybrid strains were significantly higher (P