Usefulness of probiotics in civilizing water quality and bacterial flora in fish ponds

Abstract

Fish culture aimed at high production through intense culture practices often leads not only to the
alteration in water quality but also to severe disease problems. The accumulation of organic wastes
deteriorates water quality and encourages the proliferation of pathogenic microorganisms. To avoid
these problems, probiotics are used as bioremediation tool. The present study was aimed to know the
changing patterns of beneficial and pathogenic bacterial loads and water quality in fish ponds treated
with pond probiotics. For this study, three earthen fish ponds, were cultured Pangasius sutchi, Catla
catla and Labeo rohita, located in Balliparru near Machilipatnam in Krishna District, Andhra Pradesh,
India were selected and studied for a culture period during 2009 to 2010. Two ponds were treated with
probiotics having Nitrosomonas (1.62 kg/ha) and Nitrobacter (0.82 kg/ha) species and one pond was
kept as control. During the culture period (August 2009 to July 2010), water quality parameters and the
populations of total heterotrophic bacteria (THB), beneficial bacteria (Nitrosomonas and Nitrobacter
species) and pathogenic bacteria (Pseudomonas) in water were analyzed. It was observed that in treated
ponds, THB and beneficial bacterial load increased and pathogenic Pseudomonas load decreased. The
bacterial population changed during every fortnight sampling of the culture period. The changing
patterns of different bacteria in treated and control ponds were compared and discussed. The
concentrations of ammonia, nitrite and phosphates were observed to be low in treated ponds than in the
control pond. The present study revealed that the probiotics are instrumental in maintaining good water
quality, higher beneficial and lower pathogenic bacterial loads in fish ponds.