| Abstrakt: |
Use of microalgae as a source of food in aquaculture production is gaining recognition due to their rapid growth rate that promises high biomass generation within a short time. The challenge faced is getting good and inexpensive nutrients source to be used in mass production of the required microalgae. This study investigated the effect of different nutrient combination in influencing the growth rate of the of the green algae Oocystis sp. which has been identified as a possible protein source for the raising of Orechromis niloticus fingerlings for fish farming. Modified Bolds 3 N Medium and commercial agricultural fertilizers (urea, NPK and DAP) media were compared to establish the appropriate combinations that would result into high biomass generation but at the lowest cost possible. The Modified Bold 3 N Medium acted as the control, at a cost of 11.28 KSh per litre; the other media were derived from urea, NPK, and DAP (varying the ratio of each) at a cost of treatment 1 (0.14 KSh per litre), treatment 2 (0.18 KSh per litre), and treatment 3 (0.22 KSh per litre). The algae was cultured for 5 weeks with samples taken daily for biomass analyses using chloropyhll-a concentration as the surrogate for Oocystis sp. biomass for 30 days, from each treatment was determined. The growth rate, doubling time, and divisions per day were then estimated based on this chlorophyll-a concentration. The results showed that the mean concentrations of chlorophyll-a in treatment 1 was highest (7.715 ± 0.667 µg/ml), while treatment 3 (6.441 ± 0.555 µg/ml) had the least. There were no significant differences in the mean concentrations of chlorophyll-a in the four treatments (Kruskal–Wallis H test: P > 0.05). The chlorophyll-a concentration varied significantly in each treatment with time (Kruskal–Wallis H test: P < 0.001). There was no significant difference in the growth rate (Kruskal–Wallis H test: P > 0.05), divisions per day (Kruskal–Wallis H test: P > 0.05), and doubling time (Kruskal–Wallis H test: P > 0.05) from the different treatments. The results of this study showed that inorganic fertilizers can be used as cost-effective media in the mass scale culture of Oocystis sp. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink