Abstract
Xenorhabdus and Photorhabdus bacteria are symbionts of entomopathogenic
nematodes of the genera Steinernema and Heterorhabditis, respectively. To
determine the nutrient potential of these bacteria for a free-living
nematode, Panagrellus redivivus, a promising food source for first-feeding
fish and crustacean, sterile first-stage juveniles (J1) of P. redivivus were
fed on various isolates of Xenorhabdus and Photorhabdus bacteria in liquid
cultures. Most of the tested bacterial isolates did not support the growth
of P. redivivus. However, four of the Xenorhabdus isolates (X. nematophila
All, X. bovienii T319, X. beddingii X-7 and X. poinarii KG) provided
nutrients for the production of these nematodes in a liquid medium. Two
Xenorhabdus isolates (X. beddingii X-7 and X. poinarii KG) even supported
mass production of the nematode in a sponge medium, with yields comparable
to those with yeast strains. This is the first report that Xenorhabdus
bacteria can function as a nutrient source for mass production of nematodes
other than their usual symbiotic partners.