Intestinal microflora of larval and juvenile stages in Japanese flounder(Paralichthys olivaceus).

Abstract

Investigations on the aerobic bacterial flora in the intestine of larval and juvenile stages in Japanese flounder (Paralichthys olivaceus) were carried out at two different fisheries stations. The bacterial flora of ambient water and feeds were also analyzed. The number of bacteria in the intestine of larvae measuring 10 mm in total length was 105 CFU/fish, remained nearly constant until 14 mm, and decreased to 104 CFU/fish in 15-19 mm. The decrease in bacterial numbers was hypothesized to be due to the change in feeds from live diets (rotifer and brine shrimp) to artificial diets. The bacterial numbers on ZoBell's 22l6e agar were 104, 108, 105, and 106 CFU/ml or g in water, live feeds, artificial feed and minced fish, respectively.The composition of intestinal flora was characterized by two predominating groups of Vibrio and Pseudomonas followed by Moraxella, Cytophaga and Alcaligenes. Similar generic composi tion was recovered in water and live diets, while those of artificial diets comprised of Acinetobacter and Gram-positive bacteria in addition to Moraxella.Vibrio alginolyticus was frequently isolated from fish examined in one station where no apparent fish mortality occurred.

Bacterial Flora of Milkfish, Chanos chanos, Eggs and Larvae.

“…from the results in several studies, environmental microflora markedly influence surface and some times intestinal microflora (Nieto et al, 1984;Camp bell and Buswell, 1983;Tanasomwang and Muroga, 1988;Cahill, 1990). However, this trend of relation ship was hardly achieved in this study as in the results obtained by Yoshimizu and Kimura (1976) when genus Vibrio formed as the dominant species in the intestines of salmonids cultured in seawater.…”

“…To elucidate pathogenesis of these bacterial pathogens and assess the role of gastro intestinal microflora in several marine finfishes, intestinal microflora of larval and juvenile stages were investigated (Yoshimizu and Kimura, 1976;Muroga et al, 1987;Tanasomwang and Muroga, 1988). Results obtained varied each other showing that intestinal flora were influenced mainly by flora of food ingested and/or flora of the environment.…”

Characterization of the intestinal microbiota of wild caught and farmed fine flounder (Paralichthys adspersus)

“…lensis and P. olivaceus (Tanasomwang & Muroga, 1988;Martin-Antonio et al, 2007). However, it is necessary to consider that the absence of Vibrio in WF may be due to (i) low dominance of this genus in the intestinal community, caused by the presence of bacteria with antagonistic effect against vibrios (Sun et al, 2009) or (ii) Vibrio spp.…”

Bacterial Flora of Water and Rotifers in Outdoor Mass Culture Tanks Fed with Different Microalagal Diets

“…The study also revealed that the total vibrio loads of water and rotifers were very high in C. calcitrans fed tanks, followed by tanks fed with combined diet N. occulata and I.galbana. It was observed that the diversity of the bacterial flora of rotifers is dependent on the flora of the rearing water [7] and V. alginolyticus was recorded as the most dominant microflora of rotifers, which produce a fatal exotoxin for B. plicatilis [8]. In contrary, V. anguillarum isolated and identified as the major dominant species in rotifer cultures but there was no record of mortalities due to this species [8].…”