The application of bioflocs technology in high-intensive, zero exchange farming systems of Marsupenaeus japonicus

A 106-day experiment was conducted to investigate the effectiveness of bioflocs technology for maintaining good water quality, supplying feed nutrition and inhibiting potential pathogen in high-intensive, zero exchange farming systems of Marsupenaeus japonicus. The experiment was progressed with 2 groups differentiated by bioflocs treatment and relative control in 6 indoor concrete ponds. Sucrose was added to the water of bioflocs treatment ponds based on the amount of daily feed. The monitoring indicated that ammonia-N and nitrite-N concentrations of water in the bioflocs treatment group were significantly lower than the relative control group (P < 0.05). Comparing with the relative control group, the bioflocs treatment resulted in a 41.3% higher shrimp yield, 12.0% higher protein efficiency ratio, and 7.22% lower feed conversion rate. The production of M. japonicus reached to 1.3 kg m(-2) at a body length of 11.33 cm after 106-day farming in the bioflocs treatment group. The predominant microbe analyzed with denaturing gradient gel electrophoresis (DGGE) was characterized by Bacillus sp. in the bioflocs treatment group, but by Vibrio sp. in the relative control group. It was concluded that bioflocs technology performed well in high-intensive, zero exchange farming systems of M. japonicus, and the performance may be associated with microbial diversity. (C) 2012 Elsevier B.V. All rights reserved.