EFFECTS OF POTENTIAL PROBIOTIC BACTERIA ON THE IMMUNE RESPONSE AND DISEASE RESISTANCE OF KELABAU FISH (Osteochilus melanopleurus) AGAINTS Pseudomonas sp. INFECTION

Abstract

Pseudomonas sp. as a facultative bacterium found to play a role in causing disease in cultured fish. The Kelabau fish (Osteochilus melanopleurus) is a herbivorous fish that has the potential to be cultivated, so it is necessary to control bacterial infection including those caused by Pseudomonas sp.The study evaluated the ability of three bacterial isolates originating from the Kelabau fish gut on the immune response and disease resistance against Pseudomonas sp. PS-1 infection as potential probiotics. The bacterial isolates were Staphylococcus edaphicus MT269536 (BPs2), Bacillus paramycoides MT269537 (BP3) and B. albus MT269538 (BeP1) were added to fingerling Kelabau fish with a concentration of 106 CFU mL-1 as much as 0,05 mL g-1 by spraying on the feed and Phosphate Buffer Saline solution used as control with the same dose. Fish were fed two times a day by at satiation and the addition of bacteria in the feed was done once in the morning. Feeding according to the treatment was carried out for 13 days of maintenance, on the 14th day the fish were challenged with Pseudomonas sp. PS-1 which is injected intramuscularly with a concentration of 106 CFU mL-1 at a dose of 0.1 mL fish-1. Observations on the ability of probiotic candidates bacteria against Pseudomonas sp. infection were carried out until the 21st day. The results showed that S. edaphicus MT269536 bacteria had the ability to increase disease resistance in Kelabau fish better than other bacteria after challenged with Pseudomonas sp. PS-1 with survival rates of 86.67%. The number of bacteria at the end of the observation was 1.15x105 CFU mL-1, the hematological and immune response parameters were better than other treatments.