藻类种类和浓度对中华哲水蚤(Calanus sinicus)摄食和消化酶活性的影响

通过饵料浓度差法在实验条件下研究了不同浓度的金藻、三角褐指藻和巴夫藻对中华哲水蚤(Calanus sinicus)摄食和消化酶活性的影响,结果表明:不同藻类和浓度对中华哲水蚤的摄食有明显的影响.(1)中华哲水蚤对3种饵料藻的摄食存在一饱和浓度,低于饱和浓度,摄食率随着食物浓度的增加而增加;高于饱和浓度,摄食率呈下降趋势.实验浓度下,中华哲水蚤对金藻、三角褐指藻和巴夫藻的最大摄食率分别为4664、6021 cells ml-1和4524 cells ml-1.滤水率随着食物浓度的增加而呈单一性的下降.(2)中华哲水蚤消化酶活性随藻类种类和浓度的变化而变化.不同藻类和浓度下,昆布多糖酶活性都明显高于麦芽糖酶和纤维二糖酶的活性,而麦芽糖酶活性又稍高于纤维二糖酶的活性.不同藻类喂养条件下,中华哲水蚤3种消化酶的活性发生了不同程度的变化,以巴夫藻喂养时酶活性稍高.

Effects of microalgal species and concentrations on the feeding and digestive enzyme activities of Calanus sinicus

Effects of differentiation of microalgal species and concentrations on the feeding and digestive enzyme activities of marine planktonic copepod Calanus sinicus, the key species of Yellow Sea and East China Sea, were studied by the batch culture feeding experiment under controlled laboratory conditions, and three species of marine bait microalgae: Isochrysis galbana, Phaeodactylum tricornutum, and Paviova viridis were used in this experiment. Results showed that different microalgal species and concentrations had significant effects on the feeding of C. sinicus. (1) The critical food concentration of the tested bait microalga was the key point in deciding the change of ingestion rates (IR) of C. sinicus. IR increased steadily with the microalgal concentration increasing when it was below the critical concentration, but decreased obviously when it was above the critical concentration. The maximum IR on I. galbana, P. tricornutum, and P. viridis were 4664, 6021cells ml-1, and 4524 cells ml-1, respectively. Differently, clearance rates (CR) decrease monotonically with microalgal concentration increasing during the whole experiment. (2) The digestive enzyme activities of C. sinicus changed according to the micrialgal species and concentration variation, and the change to what extent was decided by the microalgal concentration. The activity of laminarinase was higher than that of maltase and cellobiase, and cellobiase had the relatively lower activity compared to the other two in the present study. Result also showed that microalgal species played an immportant role in affecting the digestive enzyme activities. C. sinicus fed with P. viridis had relatively higher digestive enzyme activities comapred with those fed with I. Galbana and P. tricornutum, although all the changes were not reached significance (P>0.05), suggesting the complexity and variability of zooplankton feeding in response to different diets. Further study of a particular alga-herbivore system can provide the fundamental information to clarify the substance cycle and energy flow in marine ecosystems.