Enzyme production by
obligate intestinal anaerobic bacteria isolated from oscars (Astronotus
ocellatus), angelfish (Pterophyllum scalare) and southern
flounder (Paralichthys lethostigma)
R.F. Ramirez, B.A. Dixon
Aquaculture, 227(1-4): 417-426
Abstract:
The important role of the normal anaerobic intestinal
flora has been elucidated in man and some domesticated animals; however, the
presence of intestinal anaerobes, let alone their importance, in lower
vertebrates is largely unknown. The purpose of this research was to isolate
and to identify the obligate anaerobic intestinal flora of the freshwater
angelfish (Pterophyllum scalare), oscars (Astronotus ocellatus)
and the marine southern flounder (Paralichthys lethostigma).
Anaerobic intestinal flora were successfully isolated and cultivated in a
Bactron II anaerobe chamber; however, many of these isolates could not be
identified using available biochemical databases and may represent new
undescribed taxa. The types of obligate anaerobes isolated differed among
the fish, for example, only the genus Clostridium was recovered from
southern flounder, while both Clostridium and Gram negative genera
including Fusobacterium, Bacteroides and Porphorymonas
were recovered from oscars and angelfish. Isolates were tested for the
presence of constitutive enzymes using the APIZYM system. Anaerobic bacteria
isolated from the gastrointestinal tracts demonstrated enzyme activities of
acid and alkaline phosphatases, C4 and C8 esterases, C14 lipases,
arylamidases and glycosidases. Enzyme activity differed with isolates.
Generally, Gram negative genera demonstrated enzymes for the breakdown of
carbohydrates, while Clostridium demonstrated enzymes for the
breakdown of proteins. All genera produced phosphatases possibly used for
absorption of nutrients.