Role of pond lining in dynamics of Sulphur recycling bacteria in pacific white Shrimp, Penaeus Vannamei grow out culture ponds

The present investigations compares observations on the trend of total heterotrophs, total vibrios and the sulphur cycling bacteria in earthen and lined white legged shrimp Penaeus vannamei culture ponds and the influence of farm level interventions like application of exogenous probiotics. The mean total bacterial counts (TBC) of pond water and sediments were close to or above 6 log CFU/ml. The sediment samples of earthen ponds showed slightly significantly higher (P < 0.01) TBC than the water samples. The total presumptive vibrio count was 2 log 0.73 ± 0.05 CFU/ml and 2 log 3.67 ± 0.98 CFU/ml in earthen and lined ponds, respectively, which were significantly different (P < 0.01). The sulphur cycling bacteria that is sulphur-oxidising bacteria (SOB) and the sulphur-reducing bacteria (SRB) were significantly lower (P < 0.01) in lined pond compared with earthen ponds throughout the culture period. There was no significant difference in SOB and SRB populations within the systems throughout the culture period indicating their balanced role of these bacterial populations in well-managed intensive culture ponds. It can be concluded that plastic lining ponds provide better management and healthier environmental conditions and sulphur cycling bacteria can be used as an indicator of pond environmental conditions. Also, the farm level interventions like application of probiotics play a significant role in maintaining the healthier pond environment.