Effects of Dietary Supplementation with κ-Selenocarrageenan on the Selenium Accumulation and Intestinal Microbiota of the Sea Cucumbers Apostichopus japonicus.

A 30-day feeding trial was conducted to investigate the effect of κ-selenocarrageenan on the growth performance, selenium accumulation, antioxidant capacity, and intestinal microbiota of sea cucumbers Apostichopus japonicus, with different sizes (70 g ± 10 g and 100 g ± 10 g). Sea cucumbers of each size were randomly assigned into two groups; a diet without supplemented κ-selenocarrageenan was referred to as a control diet, or supplemented with κ-selenocarrageenan at selenium (Se) levels of 2.0 μg/g. Selenium accumulation in the body wall and intestine was determined on days 0, 10, 20, and 30. The survival rate (SR) was significantly higher in the κ-selenocarrageenan-treated group (Se group) than in the control group. After 30 days of feeding, κ-selenocarrageenan supplementation increased the activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC), and decreased malondialdehyde (MDA) levels in A. japonicus. Furthermore, the intestinal microbiota diversity of sea cucumbers was increased by dietary supplementation with κ-selenocarrageenan and the relative abundances of some probiotics (such as Sulfitobacter and Rhodobacteraceae) were also increased. It is suggested that κ-selenocarrageenan could increase the antioxidant capacity and modulate the intestinal microbiota of sea cucumbers A. japonicus. Further researches will be conducted for its optimal administration concentrations in vivo.