Plasticity of Respiratory Function Accommodates High Oxygen Demand in Breeding Sea Cucumbers

Abstract

Physiological plasticity allows animals to adjust their physiological function to abiotic and biotic variations. It has been mostly studied in the context of response to external factors and not much is known on how animals adjust their physiology to cope with variations in internal conditions. The process of reproduction implies gonadal maturation and other internal changes, bringing various challenges to the animal such as an increased demand for energy and oxygen. Here, the capacity of the sea cucumber, Apostichopus japonicus to adjust its respiratory function and physiological mechanisms during reproduction was studied using a time-lapse videography and metabolomics approach. The results showed that reproduction caused a significant increase in oxygen consumption in A. japonicus. Interestingly, breeding sea cucumbers can accommodate the high oxygen demand by accelerating respiratory rate. However, to maintain a necessary high level of respiratory activity during reproduction, sea cucumbers need consume large amounts of adenosine triphosphate (ATP). In addition, the metabolomic data suggests that oxidative stress and hormone regulation are the physiological mechanisms linking reproduction and respiratory function. Altogether, these findings suggest that plasticity of respiratory function is an effective tactic to cope with high oxygen demand during reproduction.

Dynamics of the Apostichopus californicus-associated flavivirus under suboxic conditions and organic matter amendment

“…While body wall PcaFV load was not reduced in the DS treatment, it was significantly lower in the respiratory tree, suggesting that in internal, seawater-filled spaces the impacts of hypoxia may be more pronounced than in external surfaces, consistent with studies of host gene expression in this organ (Huo et al, 2017). Holothurians may compensate for hypoxic conditions through accelerated respiratory rate (Ru et al, 2020), but long-term hypoxia may result in respiratory tree degradation in the absence of viruses or other pathogens (Huo Tissue (top) level response to treatment with organic matter amendments and Tube foot (bottom) response over time to organic matter amendment and dinitrogen sparging. The only significant explanatory variable for treatment was tube foot PcaFV load at 0 h (ANOVA, df=429, p<0.0001).…”

Effect of live-storage period and temperature on oxygen consumption rate in the cold-water sea cucumber Parastichopus tremulus

“…In addition to exhibiting an allometric relationship with body size (Astall and Jones, 1991;Kodama et al, 2015), a range of factors are known to affect the metabolic rate and thereby oxygen consumption rate (OCR) in echinoderms, e.g. salinity (Talbot and Lawrence, 2002), pH (Farmanfarmaian, 1966), partial pressure of oxygen, pO 2 (Shick, 1983;Spicer, 1995;Christensen and Colacino, 2000), seasonal variation in growth (Lawrence and Lane, 1982;Fraser et al, 2004), feeding status (Vahl,1984;Brockington and Clarke, 2001;Idrisi et al, 2003;Yu et al, 2020), nutritional quality of food (Otero-Villanueva et al, 2004) and reproductive state (Giese et al, 1966;Feŕal and Magniez, 1988;Ru et al, 2020). Changes in locomotory activity, such as an increase during spawning season (Ru et al, 2021), or a reduction during aestivation (Ji et al, 2008), can also impact the rate of oxygen consumption.…”