The Health-Promoting Effects of Bacillus subtilis in the Culture of Sea Cucumber

Abstract:

To study the impact of Bacillus subtilis on sea cucumber Apostichopus japonicus, the functions of the different densities of B. subtilis in the culture of sea cucumber were examined by focusing on various parameters, such as water quality, specific growth rate (SGR), activity of non-specific immune enzymes, and digestive enzymes. The results showed that B. subtilis significantly reduced the content of nitrate and nitrite in the culture water, and the highest removal rates of nitrate and nitrite were 42.28% and 22.33%, respectively. B. subtilis obviously improved the SGR of sea cucumber and the activity of non-specific immune enzymes. The density of B. subtilis did not impact on ammonia nitrogen and COD content in the culture water. At the density of 6×106, the SGR and the activity of amylase in sea cucumber tissues compared with the control group were increased by 40.74% and 30.27%, respectively. Additionally, the increasing value of the activity of peroxidase, alkaline phosphatase, lysozyme, and superoxide dismutase were 135%, 27%, 396%, and 192%, respectively. When the density of B. subtilis was 5×106, the activity of protease in sea cucumber was improved by 53.93%. These findings suggest that the appropriate density of B. subtilis in sea cucumber culture water not only improved the quality of water but also increased the activity of digestive enzymes and nonspecific immune enzymes, resulting in better growth of sea cucumber.