Different expression levels in liver tissue of broilers. (A) Representative image of 2DE gel of liver tissue from 35-day-old broilers. (B) Protein volume of each group. Values are presented as means with error bars as standard error. a-cDifferent superscript letters represent significant differences (*P < 0.05, **P < 0.01, ***P < 0.001). Abbreviations: C, control; HH, Heat stressed high weight; HL, Heat stressed low weight.