احمد شادی

Objective: In the present experiment, effect of dietary spirulina microalgae Arthrospira maxima supplementation on colour enhancement of Zebra Malawi cichlid Pseudotropheus zebra was investigated. Methods: Six experimental diets including spirulana at levels of 0 (control), 5, 10, 15, 20 and 25% were fed to a total of 180 fish for 5 weeks (initial weight of fish, 15gr, 10 individuals per group). The treatments were triplicated, fish were fed ad libitum, twice daily(8 am, 8am). Dissolved oxygen and other water quality factors were held at optimum level for tested fish. At the end of the experiment( day 35) color of fish was measured using an Image Processing software (10000*14000dpi quality). Image processing was carried out in Photoshop software using L*a*b system. Oriana 3.0.0 software and SPSS ver. 14 was used for statistical analysis ( Rayleigh test, for circular normality distribution test, Kolmogorov-Smirnov Test, ANOVA, etc.) and Excel 2007 software was used to outlining graphs and charts. Results and Discussion: The results showed that Spirulina treatment led to a significant enhancement of L mean level at all treatments. No significant difference in mortality and growth was observed between treatment groups. Optimum inclusion rate of spirulina was 15% and this resulted in a significant colour enhancement in all studied parameters compared with the control.