Cell damage associated with heat stress (HS). a Apoptosis, b LDH and c MDA are increased following heat stress, but this increase is reversed by pre-treatment with vitamin C (VC) and vitamin C-Na (VC-Na). d SOD activity decreases following heat stress, and supplementation with vitamin C and vitamin C-Na decreases basal level SOD activity at 0 h compared to controls. SOD activity is strongly increased following exposure to heat stress for 3 and 5 h, respectively. *p < 0.05, **p < 0.01compared with 0 h in the control group; #p < 0.05, ##p < 0.01 means supplements group compared with the control group or compared between the two supplements at the same timepoint