Organization, density, and content of collagen in the body wall of sea cucumbers Acaudina rosettis and Phyllophorus sp.

Marine collagen has been known to have lower immunogenicity compared to bovine collagen. The primary component in the body wall of sea cucumbers is collagen. This study aimed to investigate the density, bundle organization, and yield of collagen in the two sea cucumber species, Acaudina rosettis and Phyllophorus sp. collected from the Madura Strait, Indonesia. The body wall parts, including the dorsal anterior, dorsal median, dorsal posterior, ventral anterior, ventral median, and ventral posterior, from five samples of each species, were fixed and decalcified. They were histologically processed using the paraffin method before staining them with Van Gieson to visualize collagen in the cross-sections of body wall tissue. Collagen density was determined using the ImageJ software, while collagen bundle organization was examined negatively by utilizing the image editing application. Collagen density data were analyzed using repeated-measures ANOVA (α = 0.05). Collagen content in the body wall of each species was examined using acid solubilization-based collagen extraction, which did not significantly differ between different parts of the body wall in each species (p = 0.161 for A. rosettis, p = 0.095 for Phyllophorus sp.). However, Phyllophorus sp. exhibited a higher collagen density and collagen bundles, which were larger and more organized compared to A. rosettis. The collagen content was higher in A. rosettis (10.07%) compared to Phyllophorus sp. (8.07%). Further study can be performed to explore the potential of collagen from these sea cucumber species for commercial use.