Figure legends
Fig.1. (A) Weight gain rate (WGR), (B) specific growth rate (SGR), (C) feed conversion rate (FCR) and (D) condition factor(CF) − concentration (CK, LN, Mn and HN) of turbot larvae with different CO2 concentrations (CG, LC, MC1, MC2 and HC) (9 samples for all parameters). The parameter differences between CG, LC, MC1, MC2 and HC treatments were discovered by Tukey test using SPSS software. Different letters indicate a significant difference (P < 0.05)
Fig.2. (A) Survival Rate (SR), (B) Hepatosomatic Index (HSI), (C) Kidney Somatic Index (KSI) and (D) Spleen-Somatic Index (SSI) − concentration (CK, LN, Mn and HN) (all parameters have 9 samples). The parameter differences between CG, LC, MC1, MC2 and HC treatments were recognized by Tukey test using SPSS software. Different letters indicate a significant difference (P < 0.05)
Fig.3. Turbot larvae were exposed to different concentrations of CO2 (CG, LC, MC1, MC2, HC). After 60 days, the concentrations of (a) hemoglobin (HB) and (b) methemoglobin (MetHb) were expressed as mean ± S.E. (9 samples in each group).
Fig 4. Photographs of liver tissue sections of juvenile turbot exposed to different CO2 levels. A-1. CG, 1-month-old normal liver; A-2. CG, 2-month-old normal liver; B-1、B-2. LC, and C-1, C-2 MC1. There was only slight violation of hepatocytes at the age of 1 month and 2 months (arrow); D-1、E-1. MC2、HC. Acute vacuolization of hepatocytes (arrow) and nuclear atrophy or deformation (square) occurred at the age of 1 month; D-2、E-2. MC2、HC. At 2 months of age, there was vascular congestion (round) in the venous sinus or portal area (hematoxylin eosin staining).
Fig.5. In 60 days of CO2 exposure, (A) is glutamic oxaloacetic transaminase (GOT) in turbot plasma; (B) It is alanine aminotransferase (GPT). The data are mean ± S.E. (n = 9). The values of different superscripts were significantly different among groups (P < 0.05)
Fig.6. Effects of different concentrations of CO2 on growth related genes in GH-IGF axis during 60 days of CO2 exposure. The data are expressed as mean ± S.E. (n = 9). There were significant differences in different superscript letters among the groups (P < 0.05).