采用实验生态学方法,研究了饥饿胁迫对(鱼免)鱼(1—7日龄前期仔鱼,26—35日龄后期仔鱼,42—53日龄稚鱼)的生长、存活及消化酶(淀粉酶、脂肪酶、胰蛋白酶)活性的变化。结果表明,短期饥饿(2天)会显著降低前期仔鱼生长及消化酶活性;在后期仔鱼和稚鱼中,产生这种影响的饥饿时间分别为饥饿后3和6天,表明(鱼免)鱼仔、稚鱼的生长与消化酶活性对饥饿的忍受能力随发育生长而增强。恢复摄食5天后,饥饿4天的后期仔鱼和饥饿6天的稚鱼消化酶活性可达到正常水平,但饥饿6天的后期仔鱼的消化酶活性不能从饥饿损伤中恢复。饥饿4—6天的后期仔鱼和稚鱼的生长在恢复摄食后均未达到正常投喂组个体的生长水平,表明恢复摄食后其生长恢复过程滞后于消化酶活性。(鱼免)鱼仔、稚鱼的生长和消化酶活性可作为评价其遭受的饥饿程度和营养状况的指标。
This study investigated the effects of short-term food deprivation on the growth, survival and activities of digestive enzymes (amylase, lipase and trypsin) of miiuy croaker (Miichthys miiuy) at different developmental stages [1—7 days post hatching (dph) pre-larvae, 26—35dph post-larvae, and 42—53dph juveniles]. The results showed that the growth and activities of the digestive enzymes of the pre-larvae significantly decreased after food deprivation for 2 days, compared with 3 days in the post-larvae and 6 days in the juveniles. These observations suggest that the activities of the digestive enzymes of miiuy croaker at early developmental stages were subject to short-term starvation. However, their ability to withstand starvation may improve as they grow. After resuming feeding for 5 days, the activities of the digestive enzymes of the post-larvae that had starved for 4 days recovered to the levels of the well-fed fish. However, the digestive enzymatic activities of the post-larvae that had starved for 6 days did not recover to the levels of the well-fed fish even after feeding was resumed. In contrast, the activities of the digestive enzymes of the juveniles starved for 6 d reached the levels of the well-fed fish within 5 days after resuming feeding. These findings suggest that the activities of the digestive enzymes of the post-larvae may take more time to recover from food deprivation when starvation was prolonged. Moreover, the activities of digestive enzymes of the starved juveniles could recover more easily than those of the post-larvae after feeding was resumed. However, the growth of both the post-larvae and juveniles could not be recovered from the 4—6 days starvation even after feeding was resumed, suggesting a time lag between growth recovery and the recovery of the digestive enzymes. These findings indicated that the growth and digestive enzymes activities of the miiuy croaker larvae and juveniles were sensitive to short term food deprivation and thus can be used as useful bioindi