Seasonal variations of digestive enzymes in sea cucumbers (Holothuria tubulosa, G. 1788) under culture conditions.

Sea cucumber, Holothuria tubulosa (Gmelin, 1788), is an economically valuable species due to its rich nutrients content that being exported in Turkey. However, culture of this species is difficult due to a lack of knowledge. The main objective of this study is to investigate seasonal activities of main digestive enzymes (protease, lipase, and amylase) for nutritional requirements. In this sense, sea cucumbers were stocked in the glass aquarium and sediment was 10 cm. It was replaced monthly and enriched (1% of the living individual weight) by dried Sargassum sp. Total protease and amylase enzymes have shown higher activity compared to lipase. All three enzyme activities were maximum in the summer and minimum in the winter. In summer, the highest measured total protease, amylase, and lipase activity values were 6.45 ± 0.66, 6.77 ± 0.72, and 2.78 ± 0.32 U/mg per protein, respectively. In winter, the lowest total protease, amylase, and lipase activity values were measured as 2.03 ± 0.16, 1.14 ± 0.14, and 0.12 ± 0.01 U/mg per protein, respectively. As a conclusion of the study, seasonal expression of the main digestive enzymes was strictly dependent on water temperatures and food abundance and also it was ideal to feed this species with food containing high protein and carbohydrate under appropriate temperatures for commercial culture.

The effect of sea cucumber Holothuria tubulosa (G., 1788) on nutrient and sediment of Aegean Sea shores.

The effects of sea cucumber, Holothuria tubulosa, on sediment of hypereutrophic conditions were investigated. Research was designed as two groups with 3 replicates. And data determined from sea cucumber groups were compared to that of the control. Water samples and sediment samples were analyzed three times in a week with respect to nitrogenous materials and organic carbon. The differences between the initial and final concentrations of % C, ammonium, nitrate and nitrite were significant (p < 0.05) at the end of the 84 days of experiment. The data from the present study showed that sea cucumber played an important role in the refreshing of sea water. Therefore, it can be suggested that sea cucumbers might be successfully used for the improvement of coastal regions especially in the areas with fish farming.