Trends in Beneficial and Pathogenic Bacterial Populations and their Relation with Environmental Parameters in Tiger Shrimp, Penaeus monodon Culture Ponds

Abstract

In aquaculture pond environment, application of several inputs leads to deterioration of pond bottom resulting in build up of toxicants like, ammonia and hydrogen sulphide. Hence it is essential to understand the beneficial effects of bacterial populations involved in nitrogen and sulphur recycling and the shifts in the opportunistic bacterial pathogens. The present investigation reports the influence of farm level interventions (fermented juice, soil and water probiotics) on nitrogen [Ammonia oxidizing bacteria (AOB) and Nitrite oxidizing bacteria (NOB)] and sulphur [Sulphur oxidizing and reducing bacteria (SOB and SRB)] recycling bacteria, opportunistic pathogens (Vibrio spp.) and total cultivable bacterial load and their relation with physico-chemical parameters of soil and water in three tiger shrimp Penaeus monodon culture ponds in Gujarat, India. During the culture period variation in different bacterial populations (x103 ml-1) was observed; AOB: 4 to 28 (13±6) and 4 to 20 (12±5), NOB: 4 to 28 (12±7) and 4 to 28 (14±6), SOB: 15 to 39 (23±8) and 15 to 120 (84±74), SRB: 15 to 39 (96.5±89) and 20 to 240 (166±75) in water and sediment samples respectively. Similar fluctuation was also noticed in water and sediment with respect to populations of presumptive Vibrio count (WPVC, SPVC) and total (heterotrophic) plate bacteria (WTPC and STPC). The hardness and alkalinity in pond waters was dominated by calcium and bicarbonate: ionic concentrations relate to organic carbon in soil and total ammonia N (TAN) (r=0.51) in water, AOB and nitrate N (r=0.59), TAN and WTPC (r=0.71)/WPVC (r=0.47), SOB vs NOB were positively correlated. The study indicated the importance of both groups of recycling bacteria in maintaining the pond water parameters at optimum level and to control the opportunistic pathogens in the culture environment.