Water quality improvement of Penaeus monodon culture pond for higher productivity through biomediation

Abstract

Intensive culturing of Penaeus monodon generates considerable amount of wastes leading to the deterioration of water quality, disease outbreaks and lower yields. Recently, the application of biocontrol agents were started in ponds in order to improve yield through bioremediation. Analytical investigation of a biocontrol product (PROFS), an extensively used product of Biostadt India Ltd. was performed to determine its accuracy and applicability. It was found that four different types of Bacillus species (69×10 9 cfu/g) were present in the product. Amylase, phytase and protease activities in the product were 3.078, 4.584 and 84.154 U/g, respectively. The biocontrol treatment was applied in the ponds five times during the cultivation (120 days) of P. monodon at a dose of 1 kg/ha. The amount of total ammonia, nitrate and nitrite of the treated ponds varied from 0.418 ± 0.039 to 0.079 ± 0.028 ppm, 0.029 ± 0.008 to 0.014 ± 0.004 ppm and 0.0127 ± 0.0008 to 0.0098 ± 0.00007 ppm, respectively, which were significantly lower than the values measured for untreated ponds. The product showed antimicrobial activity against Vibrio harveyi MTCC 7954 (inhibition zone: 4.89 mm) and Vibrio vulnificus MTCC 1145 (6.41 mm). Average body weight of shrimps in treated ponds was 33 ± 2.42 g, which was 39.5% higher than the values measured from control ponds. The Vibrio count was negligible (0.12×10 5 cfu/ml) and the survival rate was 93% in treated ponds.