The aim of this study was to determine the effects of vitamin E, C, and alpha-lipoic acid additions to the feed rations on the serum glucose, lipid profile, and proteins in Japanese quails (Coturnix coturnix japonica) under heat stress. The serum levels of phosphorus, calcium, and liver enzymes were also measured. All groups were kept under 34 degrees C during the hours between 08(00) and 17(00) and the temperature was 24 degrees C during the rest part of the day. The control group (BS) was fed a normal ration without having any supplement, while the other groups had a supplementation of vitamin E (BSE), vitamin C (BSC), vitamin E+C (BSEC), and lipoic acid (BSLA). The serum glucose level was found to be lower in BSE, BSC, and BSLA groups compared to the BS group (P<0.05). The triacylglycerol (TAG) percentage was the lowest in the BSEC group (P<0.05). The diacylglycerol (DAG) percentage in the BSEC and BSLA groups was lower than the other groups (P<0.001). The cholesterol percentage in BSC, BSEC, and BSLA was higher than in the BS group (P<0.001). The polarlipid percentage was highest in the BSEC group while the lowest ones were in the BS and BSE groups. The highest level of total protein was in the BSEC group (P<0.05). The levels of albumin in the BS, BSC and BSLA groups were significantly higher than in the BSE group (P<0.05). The highest level of globulin was detected in the BSEC group while the lowest one was in the BSE group (P<0.001). The level of phosphorus was significantly high in the BSLA group (P<0.05), and the level of calcium did not differ among the groups. The levels of liver enzymes in the groups fed additives tended to decrease without having any statistical significance. In conclusion, vitamin E decreased the glucose and globulin and increased the albumin; vitamin C decreased the glucose; vitamin E+C decreased the TAG and DAG and increased the protein and globulin; the lipoic acid increased the glucose, DAG, and phosphorus.