One-step detection of matured females using immunochromatography measuring kit for aquaculture of the sea cucumber Apostichopus japonicus (Selenka)

The present study aimed to develop a gonad-stimulating substance-like peptide (GSSL) immunochromatography measuring kit (GIM-Kit) to detect females of the sea cucumber Apostichopus japonicus that are ready for the collection of matured eggs for artificial insemination in hatcheries. A. japonicus is the major species consumed in East Asian countries. With regard to the increasing demand for the species in the region, collecting the minimum number of females for hatching is beneficial for sustaining the livestock and increasing the efficiency of breeding. A prototype GIM-Kit was constructed based on the double-antibody sandwich immunosorbent assay technique using two polyclonal antibodies that were generated against a physiologically active AEIDDLAGNIDY amino acid sequence of GSSL and a 40-nm-diameter colloidal gold-tagged antibody. The GIM-Kit detected as little as 80 ng of GSSL in approximately 0.4 g mL−1 of ovaries that was diluted in distilled water. The detection time was approximately 20 min in the early (April) to mid (May) breeding season. The immunoreaction of the ovaries was high among the females during the early to mid-breeding season and low at the end of the season. Thus, the present GIM-Kit is applicable for practical use in hatcheries.