EFFECTS OF SHORT-TERM FOOD DEPRIVATION ON THE GROWTH AND ACTIVITIES OF DIGESTIVE ENZYMES OF MIIUY CROAKER MIICHTHYS MIIUY LARVAE AND JUVENILES

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 bioindicators for assessing the starvation and nutritional status of this fish during early life stages.