Development of a low-cost technology for mass production of the free-living nematode Panagrellus redivivus as an alternative live food for first feeding fish larvae.
The free-living nematode Panagrellus redivivus is a suitable food source for first feeding fish. In the present report, a new method for the mass production of P. redivivus is presented. The technique involves multiplication of the nematode in monoxenic (single microorganism: Saccharomyces cerevisiae) solid culture (fluid media supported by 1- to 4-cm(3) sponge cubes) in autoclavable plastic bags (size range: 50 x 30 cm to 75 x 67 cm). Two growing media were tested: oat-meal medium (OM), which is an oat-based medium (16.7% oat-meal flour in 0.8% saline solution), and purified ingredient medium (PIM), a semi-synthetic medium (1.64% meat peptone, 0.94% yeast extract, 12.6% corn starch, 0.24% glucose, 1.48% sunflower oil, in 0.8% saline solution). The bags were inoculated with 350 nematodes/g medium. After an average period of 12 days (11-13 days) at 25 degrees C, the average yield (number of nematodes/g medium) was 241 x 10(3) for OM and 333 x 10(3) for PIM in 12-l bags (50 x 30 cm). The production scale has currently reached a bag volume of 50 l (75 x 67 cm); using PIM and the conditions described above, it was possible to harvest more than 1.3 x 10(9) nematodes/bag (291 x 10(3) nematodes/g medium). In PIM, when sun flower oil was replaced with the same amount of fish oil or cod liver oil, yields of 259 x 10(3) and 290 x 10(3) nematodes/g medium, respectively, were attained. The technology for mass production and formulation of P. redivivus should enable fish-hatchery operators to rely on a cheap, standardised, and permanently available live food product for first feeding fish larvae.
Ricci
M
M
BioTecnologie B.T. S.r.l., Pantalla di Todi, 06050, PG, Italy. mricci.bt@parco3a.org
Fifi
A P
AP
Ragni
A
A
Schlechtriem
C
C
Focken
U
U
D000818:Animals; D018554:Avena / Q000378:metabolism; D001709:Biotechnology / Q000191:economics*; D003060:Cod Liver Oil / Q000378:metabolism; D003365:Costs and Cost Analysis; D003470:Culture Media; D005398:Fisheries / Q000191:economics*; D005399:Fishes / Q000254:growth & development*; D005523:Food Supply / Q000191:economics; D007814:Larva / Q000254:growth & development; D017168:Rhabditida / Q000254:growth & development*
D003470:Culture Media; D003060:Cod Liver Oil