The Extracellular Flux Analyzer system (EFA; Agilent Technologies) enables the high-resolution measurement of changes in oxygen levels in a 96-well plate based assay and is designed to measure the mitochondrial profile of live cell cultures. By selective application of pharmaceuticals during analysis, the EFA essentially performs a mitochondrial stress test and indicates the degree to which cells have the capacity to respond to stressors. This system has been adapted to measure fish mitochondrial profiles and has shown that reserve capacity can be predictive of survival, hatching, and growth rates.
As part of an on-going Northeast Regional Aquaculture Center (NRAC)-supported project, we have recently constructed a series of genetically related diploid and triploid oyster lines derived by crossing diploid and tetraploid NEH males with female oysters from three regional lines. The performance of resulting lines were assessed throughout their early developmental stages and are being deployed in field trials at multiple grow-out sites to support the comparison of dynamic energy budgets between diploid and triploid oysters. We have also developed the protocols to use the EFA to measure and compare the bioenergetic profiles of oyster spat from a subset of the diploid and triploid NRAC lines: NEH diploid, NEH triploid, NEH x Islip NY hybrid diploids and NEH x Islip NY hybrid triploids. Initial estimates indicate there are line specific differences in basal metabolism and mitochondrial reserve capacity. Similar differences were also noted in oyster resistance to Vibrio infections. The grow-out performance of these lines is currently being followed and we will correlate mitochondrial profiles for each line with their response to field conditions and stress-response in additional lab-based experiments.