Bacteria associated with semi-continuous culture of Brachionus plicatilis , which is used as the first food of marine fish larvae, were counted on Zobell 2216 E medium and identified. The numbers of bacteria were very high in both Brachionus (about 10 super(11) bact. per ml of digestive content) and in water (from 1.6.10 super(6) to 4.7.10 super(7) bact. per ml). The cultures were studied at driving a time when mortalities occurred frequently. The introduction of a Pseudomonas) phenon at a proportion of about 50% to the dominant microflora persisted in time and was little influenced by diet. It has been the cause of the repression of the Vibrio, Aeromonas group which was found in an unusually small proportion. It induced a lack of microflora diversity and... |