Effect of prolonged starvation on body weight and blood-chemistry in two horseshoe crab species: Tachypleus tridentatus and Carcinoscorpius rotundicauda (Chelicerata: Xiphosura)

Abstract

To determine the effect of prolonged starvation on body weight and blood-chemistry of two Asian horseshoe crab species, Tachypleus tridentatus and Carcinoscorpius rotundicauda, the animals were stocked into indoor recirculation systems under two food treatments (fed and starved) for seven weeks. Seven blood-chemistry parameters: alkaline phosphatase, calcium, cholesterol, glucose, lipase, triglyceride and total protein of plasma, were measured. During the experimental period, no significant differences of body weight were detected between the starved group and fed group in the two species. Plasma alkaline phosphatase increased slightly and then decreased. Plasma calcium remained fairly constant during the experimental period. A continuous decrease of plasma glucose in the starved treatment was observed. Additionally, cholesterol, lipase and triglyceride in the plasma increased significantly at later times, while plasma total protein remained fairly constant during the experiment. Significant interactive effects between feeding regime and starved time on some parameters were also evident in the two species. The results suggested that, for adult horseshoe crabs, starvation may stimulate a “hunger response”, which in turn might lead to consumption of some nutrient reserves in the animals. By consuming such nutrient reserves, adult horseshoe crabs can withstand prolonged starvation. The present findings contribute to the understanding of the blood biochemical aspect of the biology of T. tridentatus and C. rotundicauda, when these animals encounter starvation in the wild.