Physiological Responses of Pacific White Shrimp Litopenaeus vannamei to Temperature Fluctuation in Low-Salinity Water

Abstract

Temperature is a significant environmental factor in aquaculture. To investigate the physiological responses during temperature fluctuation (28~13°C), experimental shrimps ( Litopenaeus vannamei ) were treated with gradual cooling from acclimation temperature (AT, 28°C) to 13°C with a cooling rate of 7.5°C/day and rose back to 28°C at the same rate after 13°C for 24 h. Hepatopancreas histological changes, plasma metabolites concentrations, relative mRNA expression of unfolded protein response (UPR) pathway and apoptosis in hepatopancreas and hemocyte were investigated. The results showed that with the decline of temperature, the number and volume of the secretory cells in hepatopancreas increased significantly, the tubule lumen appeared dilatated, and the epithelial cell layer became thinner. The contents of glucose (Glu) significantly decreased to the minimum value of 13°C for 24 h. The contents of triglyceride (TG), total cholesterol (TC), and total protein (TP) increased and reached the peak of 13°C for 24 h. Alkaline phosphatase (ALP) and alanine aminotransferase (ALT) activities in plasma reached the lowest and highest value in 13°C, respectively. The expressions of all genes related to UPR and apoptosis in the hepatopancreas and hemocytes were significantly changed during the cooling process and reached the highest level of 13 and 13°C for 24 h, respectively. During re-warming stage, the histopathological symptoms got remission and each of the plasma metabolite concentrations and gene expressions returned to AT levels. These results revealed that pacific white shrimp can adapt to a certain level of temperature fluctuation by self-regulation.

Effects of Low Temperature on Antioxidant and Heat Shock Protein Expression Profiles and Transcriptomic Responses in Crayfish (Cherax destructor)

“…When the water temperature changes beyond the tolerance temperature range of poikilothermic animals, oxygen free radicals increase, antioxidant-enzyme activity decreases, oxidative damage is aggravated, and immunity becomes suppressed in the organism [ 3 , 4 ]. To adapt to the drastic changes in the surrounding environment, individuals have evolved a series of temperature stress response mechanisms, such as unfolded-protein response and apoptosis [ 5 ], activation of desaturases [ 6 , 7 ], and increased lipid metabolism [ 8 ]. In addition, as a class of molecular chaperones, heat shock proteins can prevent protein denaturation and play a critical role in an organism’s resistance to environmental stress [ 9 , 10 ].…”

Energy consumption and intestinal microbiome disorders of yellow catfish (Pelteobagrus fulvidraco) under cold stress

“…We found that glucose was significantly increasingly consumed after cold stress. Similarly, plasma glucose levels in pacific white shrimp ( Wang et al, 2019 ) and mucus glucose in gilthead sea bream ( Sanahuja et al, 2019 ) were also reduced in response to cold stress. On the gene level, we found the carbohydrate metabolism activity was decreased since the starch and sucrose metabolism, as well as the glyoxylate and dicarboxylate metabolism, were significantly downregulated.…”

Lipopolysaccharide induced unfolded protein response and related anti‐lipopolysaccharide factor expression in Pacific white shrimp, Litopenaeus vannamei

“…In this study, the activities of AST, ALT and ALP increased at 12 h after LPS injection while the histological changes in the hepatopancreas were first found at the same time. Our previous study showed that cold stress caused hepatopancreas damage and ERS, which activated UPR pathway and accelerated the apoptosis process (Wang, Qu, Yan, et al, 2019; Wang et al, 2019). Therefore, we speculated that LPS injection might cause ERS and even accelerated the apoptosis process.…”