|Feeding ecology study of the fate of poly-ß-hydroxybutyrate (PHB) as potential biological antibiotic for marine crustaceans|
Farhana, A. (2014). Feeding ecology study of the fate of poly-ß-hydroxybutyrate (PHB) as potential biological antibiotic for marine crustaceans. MSc Thesis. Universiteit Antwerpen/Universiteit Gent/VUB: Antwerpen, Gent, Brussel. 24, 45 pp.
Poly-ß-hydroxybutyrate, marine Crustacea, biological control, assimilation, assimilation efficiency, isotope tracer analysis, transgenerational immune transfer
The natural polymer, poly-ß-hydroxybutyrate (PHB) has antimicrobial and growth promoting activities. It can be degraded through biological and enzymatic activities into a water soluble short chain fatty acid monomer and is thought to be a potential biological control for diseases in aquaculture. In the present study, the marine crustacean, Artemia franciscana was used as aquaculture model organism to study how PHB works in the animal body. To trace the PHB in the body, 13C prelabeled PHB bacteria were supplied to the animals and 13C stable isotope tracer analysis was done. By means of 13C prelabelled PHB, it was observed that PHB is significantly assimilated in the tissue of Artemia franciscana nauplii. Assimilation of 13C of prelabeled PHB was measured from 2h after supplying with prelabeled PHB onwards and the assimilation of 13C increased over time. Differences in assimilation in terms of isotopic abundance, assimilation efficiency and uptake per unit biomass carbon were observed for different food types (only labeled PHB, Aeromonas hydrophila (LVS3) + labeled PHB, Dunaliella tertiolecta + labeled PHB, and Tetraselmis suecica + labeled PHB), though the differences were not significant (p>0.05). Transgenerational transfer of carbon originating from PHB was observed in the F1 generation offspring from the F0 generation parents of PHB treatment. This suggests an influence of PHB on the gonadal development and reproduction activities in the F0 generation parents of PHB treatment. However, the assimilated PHB did not provide significant protection to the F1 generation offspring against Vibrio harveyi and Vibrio campbellii infection. No significant differences of Hsp70 gene expression and Hsp70 quantity was observed in the F0 generation parents of PHB treatment but the Hsp70 gene expression in the F1 generation offspring of PHB treatment was reduced significantly as compared to the F1 generation offspring of non-PHB treatment. Overall, the present study indicates that PHB is being assimilated in animal tissue and showed for the first time that PHB is used as a carbon and energy source in marine crustaceans.