温度对中华原钩虾(Eogammarus possjeticus)摄食率和消化酶活力的影响

Effects of Temperature on the Feeding Rate and the Digestive Enzymes Activities of Eogammarus possjeticus

关键词:  中华原钩虾  温度  消化酶活力  摄食率

Key words:  Eogammarus possjeticus  Temperature  Digestive enzyme activities  Feeding rate

摘要:

采用生理生态学和酶学分析方法，测定了不同温度下中华原钩虾的摄食率和消化酶活力。结果显示，温度对中华原钩虾幼体消化酶活力的影响差异极显著(P<0.01)。在15−25℃范围内，胃蛋白酶、类胰蛋白酶及淀粉酶的活力随培养温度的升高而增加；在20−25℃范围内，胃蛋白酶、类胰蛋白酶和淀粉酶活力均处于较高水平，说明中华原钩虾幼体在此温度范围内具有较好的消化吸收能力。作为甲壳动物食性指标的淀粉酶/类胰蛋白酶活力(A/T)比值在1.2−1.5之间，说明此阶段中华原钩虾幼体偏植物食性。中华原钩虾日摄食率受温度影响显著(P<0.05)，在水温20−25℃之间，中华原钩虾幼体具有最大摄食率，其回归方程为：y = −0.754 x2+33.297 x−277.57 (R2=0.958)，最大日摄食率为89.84%。成体在20℃左右达到日摄食率的最大值，其回归方程为：y = −0.247 x2+10.463 x– 78.287 (R2=0.998)，最大日摄食率为32.47%；中华原钩虾幼体和成体饵料吸收率均随温度升高呈先上升后下降的趋势，各温度处理组幼体的饵料吸收率均高于成体。根据饵料吸收率回归方程，可得到最大饵料吸收率，幼体为59.86%，成体为56.86%，对应的温度分别为幼体21.30℃、成体21.24℃。因此，20−25℃是培育中华原钩虾的适宜水温范围。

Abstract:

he amphipod crustacean Eogammarus possjeticus is an ideal live feed for fish and shrimp. However, little is known about the optimal aquaculture conditions for this species. Here we investigated the effects of temperature on the feeding rate and digestive enzymes activities of E. possjeticus using physiological ecology method and enzymatic analysis. Our results demonstrated that there were significant differences in digestive enzymes activities between groups treated at different temperatures (P<0.01). In the range of 15−25℃ the activities of pepsin, trypsin and amylase in E. possjeticus were elevated along with the increase of temperature, especially higher above 20℃. Thus, the optimal temperature for digestive enzymes activities should be 20−25℃. The amylase/trypsin (A/T) value was used to evaluate the feeding habits of crustacean. The A/T values were between 1.2 and 1.5 with small fluctuation, which indicated that the larvae of E. possjeticus had preference to plant diets. The feeding rate of E. possjeticus juveniles was largely affected by temperature (P<0.05), and the predicted maximal feeding rate was 89.84% according to the correlation equation (y= −0.754x2+33.297x−277.57, R2 =0.958) between 20℃ and 25℃. The predicted maximal feeding rate of adults was 32.47% according to the correlation equation (y=−0.247x2+10.463x–78.287 (R2=0.998) at around 20℃. The assimilation rates were similar between the juveniles and the adults of E. possjeticus. The maximal assimilation efficiency was 59.86% for juveniles, and 56.86% for adults, and the corresponding optimal temperatures were 21.30℃ and 21.24℃ respectively. These data suggested that 20−25℃ could be an appropriate temperature range for the cultivation of E. possjeticus.