Аннотация:Polyclonal antisera made in rabbits against whole washed cells of Vibrio pelagius and Aeromonas caviae were used for detection of these bacterial species in the rearing water and gastrointestinal tract of healthy turbot (Scophthalmus maximus) larvae exposed to V. pelagius and/or Aer. caviae. The results demonstrated that this method is suitable for detection of V. pelagius and Aer. caviae in water samples and larvae at population levels higher than 103 ml−1 and 103 larva−1. Populations of aerobic heterotrophic bacteria present in the gastrointestinal tract of turbot larvae, estimated using the dilution plate technique, increased from approximately 4 × 102 bacteria larva−1 on day 3 post-hatching to approximately 105 bacteria fish−1 16 days post-hatching. Sixteen days after hatching, Vibrio spp. accounted for approximately 3 × 104 cfu larva−1 exposed to V. pelagius on days 2, 5 and 8 post-hatching. However, only 103 of the Vibrio spp. belonged to V. pelagius. When larvae were exposed to Aer. caviae on day 2 post-hatching, the gut microbiota of 5-day old larvae was mainly colonized by Aeromonas spp. (104 larva−1), of which 9 × 103 belonged to Aer. caviae. Later in the experiment, at the time when high mortality occurred, 9 × 105Aer. caviae were detected. Introduction of V. pelagius to the rearing water seemed to improve larval survival compared with fish exposed to Aer. caviae and with the control group. It was therefore concluded that it is beneficial with regard to larval survival to introduce bacteria (V. pelagius) to the rearing water.
