In Vitro screening of ammonia and nitrite-degrading bacteria isolated from broiler chicken (Gallus gallus domesticus) intestines and pond sediment of nile tilapia (Oreochromis niloticus): A preliminary study

Abstract

The high level of ammonia and nitrite is a toxic factor for both poultry and aquaculture animals that directly lead to lower economic benefits. Thus, reducing ammonia and nitrite levels is an essential key for successful culture and is also important to reduce the amount of ammonia and nitrite released into the environment. This study aimed to screen bacteria having a capacity to degrade either ammonia or nitrite in vitro. Five bacterial strains previously isolated from broiler chicken (Gallus gallus domesticus) intestine and pond sediment of Nile Nilapia (Oreochromis niloticus) were used in this study, namely IBP-1, IBP-2, IBP-3, IBP-4, and IBP-5 strains. The screenings were performed using either NH4Cl containing medium or NaNO2 containing medium to determine the ability of bacteria to reduce ammonia or nitrite respectively. The ammonia and nitrite levels were afterwards measured at the beginning (day 0: before bacterial inoculation), 24h (day 1), 48h (day 2), and 72h (day 3) after the addition of 1 ml of the bacterial suspension. The results showed that the five bacterial isolates were able to degrade the ammonia and nitrite content. The greatest reduction of ammonia was achieved by IBP-4 strain (0.00 mg/l), followed by IBP-5 strain (0.04 mg/l), IBP-1 strain (0.05 mg/l), IBP-3 strain (0.14 mg/l) and IBP-2 strain (0.19 mg/l). IBP-1 and IBP-2 strains showed the highest reduction of nitrite levels with values of 0.01 mg/l and 0.02 mg/l after 72h of bacterial inoculation. These results suggest that the five bacterial strains are potentially used for degrading toxic ammonia and nitrite.