Thesis bio-engineer in cell-gen biotechnology, by Geert Rombaut,
Faculty of Agronomic and Applied Biological Sciences, University of Gent, Belgium, 153 pp.
Summary:
Artemia nauplii were cultured for six days under monoxenic conditions. Thirty-one, random selected bacterial strains were tested, spread over seven test periods. The effect of the bacterial strain on Artemia was evaluated by means of the length and the survival of Artemia, calculated as biomass. Seven strains appeared to have a positive effect on Artemia (Pseudomonas stutzeri, Pseudomonas stanieri, Cytophaga marinoflava, Aeromonas hydrophila ANOS 2, T23 klein A (unidentified), T23 groot A MRS (unindentified) and DW8 isol 1). Another nine strains had a negative effect on the brine shrimp, six of them caused total mortality and three of them resulted in a biomass which was lower than the control treatment (autoclaved seawater). The rest of the tested strains gave no significant better or worse results than the control treatment, they appeared to have no effect on Artemia.
Bacteria, which had under monoxenic conditions a positive effect on Artemia, were tested under in vivo conditions. Microfiltrated seawater, inoculated with those strains and incubated for 48-72 h at 28 C, yielded the best zootechnical results. After 132 h, the survival and the length of the Artemia were the biggest in this treatment. The culture tanks of the other two treatments, i.e. microfiltrated (control) and BACOF-treated seawater (BACOF is a kind of aerated activated carbon filter), had all crashed, no survival was observed in those tanks after 132 h.
Analysis, based on Biolog measurements, of the microbial community in the culture medium and of the microbial community associated with Artemia, revealed that the microbial community in the culture medium, at the start of a culture, has a major influence on the microbial community which will develop. The parallelism between the rearing success and the microbial community, showed the influence of the microbiota on the success of the culture.
Manipulation of the microbial community, by adding beneficial bacteria, seem to be a good method to influence the rearing success and illustrates the possibilities of this technique.
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