Abstract

ROJAS, Margarita L.; NAVARRETE, Norma A.; ELIAS, Guillermo  and  CONTRERAS, Gilberto. Efecto de jugos vegetales sobre la producción de Daphnia pulex (Cladocera: Daphnidae) en condiciones de laboratorio. Rev. biol. trop [online]. 1999, vol.47, n.3, pp.429-435. ISSN 0034-7744.

We tested the enriching effect of radish leaf (Raphanus sativus) and spinach leaf (Spinacea oleracea) extracts when added separately to the fermented wheat bran (Triticum aestivum) for producing Daphnia pulex. The experiments were conducted in 20 l glass bottles containing 14 l of dechorinated tap water. The initial inoculation density was 200 organisms/bottle. The cultures were allowed to grow for 21 days; during this time the controls received only the fermented wheat bran (Triticum aestivum), while the test containers received either extract of radish leaf (Raphanus sativus) or that of spinach leaf (Spinacea oleracea), in addition to ferment wheat bran (Triticum aestivum). We also measured some physico-chemical variables of the medium during the experimental period. These are: water temperature, dissolved oxygen, pH, conductivity, alkalinity and total hardness. These variables remained more or less the same in all test bottles reflecting non-significant variations. After the test period, the net production of D. pulex in terms of numbers was: 1 722 organisms/bottle in the controls while that receiving radish leaf (Raphanus sativus) extract with 7 997 organisms/bottle and that with spinach leaf (Spinacea oleracea) extract with 8 921 organisms/bottle. Test of analysis of variance showed significant differences among the cultures (Fisher p< 0.005). This study showed that the enrichment of fermented wheat bran (Triticum aestivum) with spinach (Spinacea oleracea) extract was a better nourishing source of food for culturing Daphnia pulex under laboratory conditions.

Keywords : Daphnia pulex; Cladocera; net production; source of food; radish leaf (Raphanus sativus) extract; spinach leaf (Spinacea oleracea) extract; laboratory conditions.