Effect of fasting on molting and survival rate in post-larvae of the shrimp Litopenaeus vannamei

Abstract

The objective of the present study was to evaluate the effect of different fasting periods on mortality of Litopenaeus vannamei post-larvae and the time it took to molt or die. The study applied an experimental design using 20-days-old post-larvae (PL), with a control group subjected to continuous feeding (CF) and 9 treatments (S2, S4, S6, S8, S10, S12, S14, S16, S18) with varying fasting periods, followed by continuous feeding. The time at which food deprivation resulted in death was analyzed for 50% of the post-larvae, even when they received food after fasting. Statistical analysis of time to molt identified 3 different groups (P < 0.05): group 1 with continuous feeding, group 2 with fasting periods of 2 and 4 days (S2, S4), and group 3 with fasting periods between 6-18 days (S6-S18). In control group with continuous feeding, the time to molt was estimated at about 3.44 ± 0.68 days. Time to death, showed 2 significantly different treatment groups (P < 0.05). In CF treatment, all PLs survived. The first group consisted of fasting tests for 2 and 4 days (S2, S4). The second group corresponded to fasting periods from S6 to S18 days, resulting in the shortest time to death with 71.43 and 100% of individuals dead. The PNR50 was estimated to be around 3.97 ± 0.31 days, demonstrating that fasting periods affected development and potentially caused death in PL of L. vannamei.