[Effects of food concentration on population growth, body size, and egg size of the freshwater rotifer Brachionus angularis]

With the food Chlorella pyrenoidosa and the method of population accumulative culture, the effects of food concentration on the population growth, body size, and egg size of the freshwater rotifer Brachionus angularis were studied. The results showed that there were very significant effects of food concentrations on the population growth rate, body size and egg size. The relationship between the population growth rate and the food concentration was curvilinear correlation. When the food concentration was 8.2453 x 10(6) cells.ml-1, the population growth rate reached it's maximum, 0.6085 d-1. Body size tended to enlarge with increasing food concentration. At the intermediate range of food levels between 6.0 x 10(6) cells.ml-1 and 9.0 x 10(6) cells.ml-1, the egg volume was larger than those at the other food concentrations.