Abstract

LEAL, Sylvia et al. Concentration and organic and proximate compositions of two benthic diatoms species at different salinities. Universidad y ciencia [online]. 2013, vol.29, n.1, pp.45-52. ISSN 0186-2979.

Navicula germanopolonica and Amphora sp, benthic diatoms isolated in Cuba, may be used to feed shrimp postlarvae, thus the importance of establishing optimum conditions for cultivation. This study evaluated the effect of salinity on the concentration and the organic and proximal composition of these species. Five salinities were tested (20, 25, 30, 35, 40 ups). Concentration was recorded by direct count. Dry and organic weight were recorded by filtering a certain volume of sample through fiberglass filters, together with the quantity of proteins, carbohydrates and lipids. Percentages were determined following the usual methods. N. germanopolonica presented its greatest concentration at 30 ups. The quantity of proteins, carbohydrates and lipids was greatest at low salinities, with 26 %, 11 % and 26 % respectively at 20 ups. Amphora sp reached its greatest concentration at 35 ups. The proximal composition recorded its greatest values at 20 ups. N. germanopolonica recorded greater densities and protein values, however, having smaller cells, the cultures need to be very concentrated to be used in feeding. The lipid content in both species was high compared with other planctonic microalgae species. N. germanopolonica provided best results at salinities below 25 ups and Amphora sp at salinities around 30 ups.

Keywords : benthic diatoms; microalgae cultures; salinity; organic composition; proximal composition; Navicula; Amphora.