Abstract
The effects of dietary poly-beta-hydroxybutyrate (PHB) on the lipid and fatty acids (FA) in crustaceans were investigated usingArtemiaas model species. Supplying PHB either in crystalline or amorphous form significantly increased the whole-body lipid contents of starvedArtemia. Co-supplying dietary PHB with bacterial PHB degraderComamonas testosteroniat 10(6) cells ml(-1) for 24 hr also significantly increased this parameter. These findings have important implications on the lipid-saving effects of PHB in crustacean tissues. Dietary PHB, however, did not contribute to the increase in docosahexaenoic acid (DHA) of the naturally DHA-deprivedArtemia. Alternative strategy of co-supplying dietary PHB with highly unsaturated fatty acid (HUFA)-rich emulsion for 24 hr effectively improved the nutritional contents ofArtemiaand at the same time assured efficient delivery of PHB to the larval predator. According to a C-13 stable isotope tracer study, the significantly higher delta C-13 levels measured inArtemia2 hr postfeeding with C-13-labelledR. eutropha DSM545 indicate that PHB offered in natural matrix is rapidly assimilated. Overall, this study demonstrated the lipid-saving effects of PHB inArtemia. PHB assimilation following gastrointestinal degradation could attribute to its reported beneficial effects in various aquatic farmed species.