Temperature and fasting effect on compensatory growth and transcriptomic response in the Pacific white shrimp Penaeus vannamei

During the cultivation of the Pacific white shrimp, Penaeus vannamei, environmental modifications can generate stress and alter the expected growth of organisms. When stress is temporary and conditions for growth are restored, shrimp may exhibit an accelerated growth rate known as compensatory growth (CG), reaching partially or fully the weight of non-stressed organisms. However, the CG response capacity is limited, and a point of no return (PNR) occurs when stress is extreme. The aim of this study was to evaluate the effect of temperature changes and temporary fasting on the transcriptomic CG response of P. vannamei. Post-larvae (0.75 ± 0.05 g avg. wt.) were exposed to different stress periods with fasting for 3, 7, and 14 days at three temperatures each (22 °C, 26 °C, and 30 °C), followed by a recovery stage of feeding ad libitum and temperature at 30 °C for the remaining time of five experimental weeks. Treatments were compared with a control group fed to satiety at 30 °C throughout the experiment. Specific growth rate (SGR, % day−1), weight gain (WG), survival (S), feed intake (FI), and feed conversion ratio (FCR) were determined weekly, and muscle was sampled for differential gene expression (DGE) analysis. Organisms exposed to 3 days of fasting reached the same weight as the control group, which indicated a complete CG. Within this group, those submitted to 26 °C showed lower FI and FCR than shrimps exposed at 22 °C and 30 °C (8% less feed consumption), suggesting a more efficient use of nutrients from the diet. On the other hand, the organisms exposed 14 days to fasting reached a PNR, and the WG reduction was >50%. The DGE concerning the control group showed 862 genes during CG and 449 genes in shrimps that reached the PNR. Up-regulation of genes related to energy homeostasis, muscle growth, and molting was observed during CG, whereas those involved in the cellular response to DNA damage stimulus were down-regulated. In contrast, genes related to oxidative stress response were up-regulated, and genes involved in molting and metabolic processes were down-regulated in organisms that reached a point of no return. Short-term fasting is an effective strategy to optimize feed use in shrimp farming without decreasing the final biomass.