Comparison of the growth of Spirulina sp. in feed formulas containing rice straw fermentation liquid as an ingredient at different levels.

The objective of this research was to study the effects of different feed formulas on the growth of Spirulina and water quality in terms of temperature, pH and light intensity. The experiment was designed with completely randomized design (CRD), divided into 3 sets of treatments with different feed formulas with 3 replicates, using formula 1(Zarrouk’s medium as control formula); formula 2(Zarrouk’s medium mixed with 100 ml/1,000 ml of rice straw ferment liquid), and formula 3(Zarrouk’s medium mixed with 200 ml/1,000 ml of rice straw ferment liquid) with 10 days cultured period provided with 24-hour light cycle. The growth efficiency was measured by measuring the average of Optical Density (OD), using a spectrophotometer at the wavelength of 560 nm. The results showed that the growth rate of Spirulina cultured with formula 1 was a statistically significantly different level of 95 % confidence (p<0.05) with, the growth rate of Spirulina cultured with formula 2 and 3. While the growth rate of Spirulina cultured with formulas 2 and 3 was not statistically different at a statistical significance level of 95 % confidence (p>0.05). In terms of water quality throughout the Spirulina culture, the temperature and pH values were in the range of 26.80±0.53 - 32.40±0.30 °C and 9.46±0.05 - 10.12±0.09, while the light intensity values were in the range of 1,125 - 1,950 lux, respectively [ABSTRACT FROM AUTHOR]