Application of fermented bran and probiotics to enhance mass-scale production of Phronima sp. in the pond

This study aimed to evaluate the efficacy of utilizing probiotics and organic matter as nutrients for Phronima sp. mass cultures in ponds. Culture media, which had water depths of 40 cm was added to the pond plots (35×30×0.4 m), then sterilized and neutralized. Organic fertilizer (70 kg/1000 m 2 ) was spread, and after 3 days the inorganic fertilizer was spread in the form of ZA (20 ppm), TSP (5 ppm), and NPK (5 ppm). Rice bran, a by-product of rice production, was fermented with molasses for a week, with a dosage of 1:0.25. Fermented bran mixed with probiotics (ratio of 1:1) was used as daily feed. Phronima sp. was spread with a density of 137 individuals/m 2 . The population density was monitored weekly. The test results showed that the growth pattern of Phronima sp. formed a sigmoid curve consisting of the lag phase, specific growth rate, population peak, and death phase. There was a significant population increase from the fourth to the seventh week, with a peak population density in the seventh week, reaching a density of 87,300 ± 6,526 individuals/m 2 . In the eighth week, the population density drastically decreased to only 10% of the peak.