| Brachionus calyciflorus is one kind of rotifers in the freshwater. It is important on material cycling and energy transfer in the water ecosystem; and it is useful for aquiculture, namely it is the starting food of some animals in the water.The experiment was conducted in the key laboratory of animal biology of Chongqing Normal University to study on effecting of several environmental factors on population growth of Brachionus calyciflorus and in vitro digestion of trypsin on Brachionus calyciflorus. The main contents were showed as following:Effect of initial population densities, food quantities, temperatures, photoperiod and pH on population growth of Brachionus calyciflorus. Brachionus calyciflorus could growth faster when the condition of culture were 30℃, initial population densities about 20 individuals/ml, pH 8.00 and 5g of yeast for a hundred million individuals of rotifer per day.Effects of initial population densities and temperatures change on resting eggs formation were researched. Initial population densities were chosen from 4 grads ( 5 individuals/ml, 15 individuals/ml, 20 individuals/ml and 35 individuals/ml ). The experiment indicated that resting eggs formation with initial population densities of 35 individuals/ml were higher than other grads. The numbers of resting eggs were 47 individuals/ml, 156 individuals/ml, 257 individuals/ml and 346 individuals/ml in turn. Temperatures change experiment indicated that rising temperatures inducement could gain more numbers of resting eggs than falling temperatures inducement, the population growth rate were 49.8% and 43.7%.Trypsin from tilapia was used to digest rotifer Brachionus calyciflorus and fish feedstuff in 48 hours under the condition of 25℃, pH 9.00. It was showed that rotifer was easily digested compared with fish feedstuff.The protein content of rotifer and fish feedstuff were 62% and 38% before digestive tests, but they were changed to be 34% and 32% after digestive tests with trypsin of tilapia in 48 hours. The digestive rate of rotifer was 45.2%, but fish feedstuff was 15.8% only. |
