Factors inhibiting growth of the rotifer Brachionus plicatilis in high density cultivation by feeding condensed Chlorella

Abstract

In order to investigate the factors inhibiting the growth of rotifer (S-type) in high density cultivation, a series of experiments were conducted, cultivating rotifer in 30l and 1kl vessels by feeding condensed Chlorella. Although there was no difference in the maximum population of rotifer in the culture experiments at different temperatures of 24, 28, and 32°C, the growth rate increased as the culture temperature increased. In the cultivation system supplied with air, the maximum rotifer population did not exceed 4, 000-5, 000 individuals/ml because oxygen levels were restricted due to the accumulation of undissociated ammonia. Feeding oxygen gas to the rotifer culture system enabled high density cultivation with a population of 20, 000 individuals/ml. In such an oxygen-rich culture system, the concentration of undissociated ammonia is considered to be the main factor inhibiting the growth of rotifer.