Effects of water temperature on digestive protease activity and apparent nutrient digestibility in Pacific whiteleg shrimp, Litopenaeus vannamei (Boone, 1931)

Abstract

Water temperature strongly influences metabolic rate, digestive physiology, and nutrient utilization in poikilothermic aquatic species such as shrimp. This study evaluated the effects of two culture temperatures (27 and 31 ◦C) on growth performance, apparent nutrient digestibility, hepatopancreatic protease production, and protease activity in Pacific white shrimp (Litopenaeus vannamei). Adult shrimp (≈16 g) were maintained at the experimental temperatures for 21 days, following a gradual acclimation period. Growth performance and apparent digestibility coefficients (AD) of dry matter, protein, methionine, and lysine were not significantly affected by temperature. However, lipid digestibility was significantly higher at 27 ◦C. Shrimp reared at 27 ◦C also exhibited a significantly higher hepatosomatic index and greater total quantity of stored protease throughout the circadian cycle, indicating enhanced digestive enzyme synthesis. Although protease catalytic activity was higher at 31 ◦C, shrimp maintained digestive efficiency at 27 ◦C through compensatory increases in enzyme production and lipid utilization. These findings demonstrate that L. vannamei exhibits substantial digestive plasticity, allowing maintenance of growth and protein utilization at moderately sub-optimal temperatures through coordinated metabolic and enzymatic adjustments.