Study of filtration, digestion and absorption of Chlorella pyrenoidosa by juvenile Chinese mitten crab (Eriocheir sinensis)

Abstract

While previous studies have reported that the zoea and megalopa stages of Eriocheir sinensis can filter phytoplankton in water bodies, it remains unclear whether juvenile crab (E. sinensis) possess the same ability. The objective of this study was to investigate whether juvenile crabs (average body weight 9.51 ± 1.57 g) can filter and absorb phytoplankton. Firstly, stomach and intestinal contents of juvenile crabs were analyzed, and their filter-feeding ability was tested under different pellet feed ratios using a blood cell counter. It was found that juvenile crabs cultured in Chlorella pyrenoidosa suspension contained large quantities of the algae in their stomach and intestinal contents compared to the control group, which were cultured with no C. pyrenoidosa. Additionally, the filtration rate of juvenile crabs to C. pyrenoidosa decreased with the increase of pellet feed proportion. Finally, the ability of juvenile crab to digest and absorb C. pyrenoidosa was studied through 15N stable isotope labeling technology. The δ15N values in muscle and intestinal tissue of group filtered with 15N labeled C. pyrenoidosa were significantly higher than group filtered with unlabeled C. pyrenoidosa and control group. The results indicated that juvenile crab could filter, digest and absorb C. pyrenoidosa, expanding our understanding of the feeding ecology of this species. This has significant implications for the ecological culture of E. sinensis and the potential for sustainable aquaculture practices.