Litopenaeus vannamei transcriptome
Healthy adult shrimps were obtained from the Rudong base of the Institute of Oceanology & Marine Fisheries, Jiangsu, Nantong, China. Shrimp was temporarily cultured in the indoor tank for 7 days before the experiment. During this period, 1/3 volume of filtered, precipitated and fully aerated seawater (24C  0.5C) was replaced daily, bait was fed regularly, and dead shrimp, residual bait and excreta were cleaned up in time. Three hundred neatly sized and healthy shrimp were randomly selected and divided into three 1000 L PVC drums as three replicates (the experimental conditions were consistent with those during the temporary storage period), and all shrimp were adapted to the drum for 2 days before the experiment. The starting temperature of the experiment was set at 24 C and was automatically cooled by a chiller at a rate of 2 C/2 h. Then, the cooling was stopped when the water temperature reached the predetermined temperature (22, 20, 18, 16, 14, and 12 C) and remained stable for 22 h. During this period, these temperature points (24 C/CK (control group), 20 C/T1, 18 C/T2, 14 C/T3, and 12 C/T4) were set as sampling points, and shrimps were randomly selected from each temperature point and placed on ice until anesthesia. Hemolymph (150 uL ) was obtained from the ventral sinus of the shrimp with a 1 mL sterile syringe and mixed with an equal volume of ice-cold ACD anticoagulant solution (1.32% sodium citrate; 0.48% citric acid; 1.47% glucose) into the centrifuge tube. Hemolymph samples from 3 shrimp per replicate were collected at each point (CK, T1, T2, T3, T4) for physiological analysis. Eighteen shrimp (6 shrimp from each of the 3 drums) were randomly selected at the CK, T2, and T4 points, were collected and centrifuged at 4 C and 5000 r/min for 10 minutes to obtain hemocytes and serum. The separated hemocytes were processed for RNA extraction, and the serum was analyzed for metabolomics. All samples for physiological, transcriptome, and metabolome analysis were rapidly frozen in liquid nitrogen and stored at -80 C.