Improvement in the growth performance of white shrimp,Litopenaeus vannamei, by a protease-producing probiotic,Bacillus subtilisE20, from natto

Autor: Chun-Hung Liu, P.-L. Ho, Chiu-Shia Chiu, S.-W. Wang
Rok vydání: 2009
Předmět:
Zdroj: Journal of Applied Microbiology. 107:1031-1041
ISSN: 1365-2672
1364-5072
DOI: 10.1111/j.1365-2672.2009.04284.x
Popis: Aims: To isolate and identify a benefic bacterium, Bacillus subtilis E20, from natto (fermented soybeans), and incorporate it into shrimp feed to promote shrimp growth performance. Methods and Results: A protease-producing bacterium, E20, isolated from natto was identified as B. subtilis by an API 50 CHB kit and the 16S rDNA sequence. B. subtilis E20 was able to grow at a broad range of temperatures (10–50°C), pH values (5–10), and NaCl levels (0–9%). The best culture conditions for B. subtilis E20 to produce the protease were 40°C, a pH of 6–8 and 0% NaCl. No shrimp died after being injected with B. subtilis E20 [up to 109 colony-forming units (CFU) per shrimp]. Bacillus subtilis E20 was incorporated in diets at the levels of 0 (control), 106, 107, and 108 CFU kg−1 for shrimp grow-out culture, and results showed that after feeding on B. subtilis E20-containing diets (108 CFU kg−1 of diet), shrimp had excellent growth performance and production compared to the control because protease activities in the digestive tract were improved by B. subtilis E20. Conclusions: Bacillus subtilis E20 isolated from natto is a great protease producer and is able to improve shrimp growth performance through increasing the digestibility of food. Significance and Impact of the Study: Results suggest that B. subtilis E20 is a potential candidate for use as a probiotic to improve shrimp growth performance, and consequently reduce feed costs.
Databáze: OpenAIRE