The effects of high seawater PCO2 on protein oxidative damage and ubiquitination in Penaeus vannamei.

High environmental PCO2 in aquatic systems typically impairs physiology and performance in ectotherms; however, the effects of high PCO2 on protein degradation, a key process in protein homeostasis and growth, remain poorly understood. In this study, we investigated the effects of increasing environmental PCO2 (ambient, 5000 and 10,000 µatm) on metabolism, oxidative stress and protein ubiquitination (an indicator of protein degradation) in whiteleg shrimp (Penaeus vannamei). Standard metabolic rate was elevated by >2-fold at 5000 and 10,000 µatm PCO2, but this was not associated with increased post-prandial oxygen consumption or oxidative protein damage. However, levels of protein K48 ubiquitin were reduced by up to 10-fold at 10,000 µatm PCO2 compared with ambient controls, suggesting high PCO2 severely affects protein degradation. Our findings reveal that while P. vannamei appear resistant to elevated PCO2, fundamental modifications to protein degradation and homeostasis may affect long-term performance and growth in this species.