Hope the attached would help.

The basic ingredients  of the sea cucumber feed are sargassum  meal,wheat gluten wheat flour,brew yeast,fish meal,dehulled soybean meal and vitamins and minerals premix

Hi Md

I don't have many articles looking specifically at commercial diets for sea cucumbers but the following paper has some formulations which may help.

Yu, H.-B., Gao, Q.-F., Dong, S.-L., Wen, B., Hou, Y.-R., Ning, L.-G., 2015. Utilization of corn meal and extruded soybean meal by sea cucumber Apostichopus japonicus (Selenka): Insights from carbon stable isotope analysis. Aquaculture 435, 106–110. 

Thanks a lot...