Laboratoire d’Aquaculture et de Démographie des Ressources Halieutiques ; Département d’Aquaculture de l’Institut de Sciences Halieutiques de l’Université de Douala à Yabassi ; BP 7236, Douala, Cameroon
Cyanobacteria Arthrospira platensis var Toliarensis is a food source with high nutritional qualities due to the diversity and richness of its constituents. However, its production in a synthetic medium is very expensive given the high requirements in mineral elements of this micro-algae. The present study conducted at the Spirulina Production Pilot Unit of the Institute of Fisheries and aquatic Sciences of the University of Douala at Yabassi aimed to evaluate the effect of the different doses Manihot esculenta Crantz (Casava) and Laportea aestuans leaves extracts on biomass production and nutritional characteristics of postharvest dry biomass of Arthrospira platensis. To achieve this objective, 11 experimental culture substrates were developed, 10 of which were based on extract of Manihot esculenta leaves at different doses (10 g / l, 20 g / l, 30 g / l, 40 g / l, 50 g / l) and based on extract of Laportea aestuans doses (at the same doses are respectively 10 g / l, 20 g / l, 30 g / l, 40 g / l, 50 g / l) and 1 referential medium ( Modified Jourdan medium). ). All the media previously prepared were subsequently seeded with 5 ml / l of a strain of Arthrospira platensis for each respective medium. A daily check of the physicochemical parameters was carried out, as well as weekly harvests in order to evaluate the productivity of each culture medium. A characterization of nutritional parameters (quantification of proteins, carbohydrates, lipids, phycocyanin and moisture) of post harvest biomasses from different media was made later. A comparative analysis of dry biomass obtained from different experimental culture media based on Manihot esculenta leaf extract at different doses (10 g / l, 20 g / l, 30 g / l, 40 g / l, 50 g / l l) and those with the extract of Laportea aestuans doses (respectively at doses of 10 g / l, 20 g / l, 30 g / l, 40 g / l, 50 g / l) compared to the reference medium of Jourdan shows a significant difference (P˂ 0.05) between treatments. The culture medium at a dose of 50 g / l of Laportea aestuans (M11) had a significantly greater effect on biomass production than all other experimental media with an average biomass of 5.65 ± 0.32 g / l. These results are also reflected in the better nutritional profile of post-harvest biomass from this environment, particularly their protein content (an average of 55.44 ± 0.38%) and carbohydrate (an average value of 33.93 ± 5.45%) in lipid (9.97 ± 1.11) in moisture (16.30 ± 4.66%) but also in phycocyanin (11.66 ± 2.97%) compared to other experimental media.