Hybrid abalone are more robust to multi-stressor environments than pure parental species

Abstract

Many hybrids of marine molluscs show improved growth in comparison to their pure parental species. Yet, little is known about the physiological mechanisms underlying the better hybrid performance. In this study, movement, oxygen consumption rate () and heart rate were determined in 22 month old cultured abalone Haliotis rubra, H. laevigata and their interspecies hybrid, the latter of which exhibits improved growth rate. Abalone were exposed to an acute temperature increase following acclimation to 16 or 23°C at high and low oxygen levels (100% or 70% air saturation, respectively). Movement of hybrids and H. laevigata was generally not affected by temperature and oxygen levels, yet H. rubra showed a strong thermal response. Heart rate and /temperature slopes revealed that hybrids were least affected by oxygen levels. Arrhenius break-point temperatures of hybrids and H. laevigata, but not H. rubra, were generally higher when abalone were acclimated to 23°C in comparison to 16°C. Hybrids had more stable maximum heart rate and values across acclimation conditions in comparison to H. laevigata and H. rubra. Thus, it appears that hybrids are able to maintain physiological functions over a broader environmental range. This improved tolerance to environmental fluctuations may bolster energy metabolism and improve growth in variable environments such as aquaculture farms.

Different Transcriptomic Responses to Thermal Stress in Heat-Tolerant and Heat-Sensitive Pacific Abalones Indicated by Cardiac Performance

“…The Arrhenius breakpoint temperature (ABT) of cardiac performance has been used as an indicator for heat tolerance in porcelain crabs ( Petrolisthes ) (Stillman and Somero, 1996), marine snail ( Tegula ) (Stenseng et al, 2005), limpets ( Cellana ) (Dong and Williams, 2011; Han et al, 2013), and scallops (Xing et al, 2016). The ABT also has been shown to be a credible, non-invasive indicator of heat tolerance in abalone (Chen et al, 2016; Alter et al, 2017).…”

Study of hybrid and backcross abalone populations uncovers trait separation and their thermal resistance capacity

“…Harmful end‐products such as reactive oxygen species (ROS) would also be produced and accumulated under heat stress (Lushchak, 2011). Methods such as ABT of cardiac performance, median lethal temperature (LT 50 ), critical thermal maximum (CTM) and Kaplan‐Meier survival curves have been widely used to evaluate the thermal resistance of marine mollusks (Alter et al, 2017; Chen et al, 2016). In this study, ABT was used to evaluate the thermal resistance of purebreds, hybrids and backcrosses.…”

Allele‐specific expression and gene regulation help explain transgressive thermal tolerance in non‐native hybrids of the endangered California tiger salamander (Ambystoma californiense)

“…These mechanistic differences that evolve in isolation may result in unique, but roughly equivalent, strategies for tolerating stressful temperatures. If such independent lineages come back into contact and hybridize, their unique mechanisms can combine to produce phenotypes that exceed either parental species (ex: Alter et al, 2017; Bidani et al, 2007; Perry et al, 2001).…”