A simple inland culture system provides insights into ascidian post-embryonic developmental physiology

Abstract

AbstractMaintenance and breeding of experimental organisms are fundamental to life sciences, but both initial and running costs, and hands-on zootechnical demands can be challenging for many laboratories. Here, we aimed to further develop a simple protocol for reliable inland culture of tunicate model species of theCionagenus. We cultured bothCiona robustaandCiona intestinalisin controlled experimental conditions, with a focus on dietary variables, and quantified growth and maturation parameters. From statistical analysis of these standardized datasets, we gained insights into the post-embryonic developmental physiology ofCiona, and inferred an improved diet and culturing conditions for sexual maturation. We showed that body length is a critical determinant of both somatic and sexual maturation, which suggests the existence of systemic control mechanisms of resource allocation toward somatic growth or maturation, and supports applying size selection as a predictor of reproductive fitness in our inland culture, to keep the healthiest animals at low density in the system. In the end, we successfully established a new protocol, including size selection, to promote both sperm and eggs production. Our protocol using small tanks will empower researchers to initiate inlandCionacultures with low costs and reduced space constraints.