This research investigates the effects of adding vitamin E, vitamin C, vitamin E+C, and alpha lipoic acid to feed rations for Japanese quails (Coturnix coturnix japonica) exposed to heat stress. The aspects studied were growth performance, carcass composition and breast meat characteristics. Five groups of quails, containing 50 birds each (250 Japanese quails: 150 female and 100 male) were used. The 21-days-old birds were fed for a period of 21 days, and they were kept in a controlled environment with a temperature of 34˚C between 08:00 and 17:00 and a temperature of 24˚C for the remaining part of the day. The five groups under study included: a control group without any additive (BS), a group fed diets with vitamin E (BSE), with vitamin C (BSC), with vitamin E+C (BSEC) and with lipoic acid (BSLA). The supplement additions to the diets did not affect the growth performance and carcass composition of the birds. The TBA (malonaldehyde) value of the BS group was significantly higher (P < 0.001) than in the other groups. L*, a*, and b* values in muscle samples, superficialis pectoralis muscle (SPM) and deep pectoralis muscle (DPM), were determined. In the samples from the SPM, the L* value of the BS group was higher than in the BSC group; the a* value of the BSE group was higher than in the BS group; and the b* value of the BSC group was higher than in the BS group (P < 0.05). In the samples from the DPM, the L* value of the BS group was higher than in the BSEC group (P < 0.05); the a* values of the BSE and BSEC groups were higher than in the BS group (P < 0.05); and the b* values of the BSC, BSEC and BSLA groups were higher than in the BS group (P < 0.01). In the microbiological analysis of meat, total aerobic mesophilic bacterial counts of the BS and BSE groups were higher than the counts in the BSC, BSEC, and BSLA groups (P < 0.01); coliform bacterial counts were higher in the BSE group than in the BSC group (P < 0.05); and lactic acid was higher in the BSE and BSEC groups than in the BSC and BSLA groups (P < 0.01). In conclusion, the supplemented antioxidants did not exhibit any significant effect on growth performance, but they significantly decreased lipid oxidation in the meat.
Laying performance, digestibility and plasma hormones in laying hens exposed to chronic heat stress as affected by betaine, vitamin C, and/or vitamin E supplementation