A high throughput method to assess the hypoxia tolerance of abalone based on adhesion duration

Abstract

To alleviate the economic losses induced by hypoxia, it is useful to accelerate genetic improvement in the aquaculture industry and breed hypoxia-tolerant varieties. An accurate phenotype assessment is fundamental to the study of hypoxia tolerance in marine organisms. In this study, a high-throughput assessment method, termed hypoxia adhesion duration (HYAD), was developed based on the change in the adhesion capacity of abalone under hypoxic exposure. To confirm the viability of the HYAD method, the hypoxia tolerance of Haliotis discus hannai and its hybrid with H. fulgens (H. discus hannai ♀ × H. fulgens ♂) was measured and compared. Enzyme activities associated with antioxidation and apoptosis, such as those of superoxide dismutase (SOD), catalase (CAT), and caspase-8, were detected to characterize the physiological status of abalone before and after the loss of adhesion capacity. The results highlighted greater hypoxia tolerance in hybrid abalone, possibly due to higher antioxidant capacity and cellular protection. The HYAD value increased with thermal acclimation duration (8 and 12 d), decreased with abalone age (9 and 33 months), and was not affected by abalone sex. The HYAD method is high-throughput, accurate, and easy to use, supporting individual and population detection. This method will allow the selection and retention of hypoxia-tolerant abalone individuals and populations for further genetic breeding.