poses a major problem for the larviculture of penaeid shrimp. In this study, a poly-bhydroxybutyrate
(PHB) accumulating mixed bacterial culture (mBC; 48.5% PHB on cell dry
weight) and two PHB accumulating bacterial isolates, Bacillus sp. JL47 (54.7% PHB on cell
dry weight) and Bacillus sp. JL1 (45.5% PHB on cell dry weight), were obtained from a
Philippine shrimp culture pond and investigated for their capacity to improve growth,
survival and robustness of Penaeus monodon postlarvae (PL). Shrimp PL1 and shrimp PL30
were provided with the PHB containing bacterial cultures in the feed for 30 days followed
by, respectively, a challenge with pathogenic Vibrio campbellii and exposure to a lethal
dose of ammonia. Prior to the pathogenic challenge or ammonia stress, growth and
survival were higher for shrimp receiving the PHB accumulating bacteria as compared to
shrimp receiving diets without bacterial additions. After exposure to the pathogenic
challenge the shrimp fed PHB accumulating bacteria showed a higher survival as
compared to non-treated shrimp, suggesting an increase in robustness for the shrimp.
Similar effects were observed when shrimp PL30 were provided with the PHB
accumulating bacterial cultures during a challenge with pathogenic V. campbellii through
the water. The survival of shrimp exposed to lethal ammonia stress showed no significant
difference between PHB accumulating bacteria-fed shrimp and non-PHB treated shrimp.
The data illustrate that bacilli capable of accumulating PHB can provide beneficial effects
to P. monodon post-larvae during culture in terms of growth performance, survival and
resistance against pathogenic infection and ammonia stress. Further investigations are
required to verify the PHB effect of the bacterial cultures on the shrimp.