Effects of vitamin C and E dietary supplementation on erythrocyte parameters of layer chickens reared in high ambient temperature and humidity

摘要

A 30-day experiment involving 720 White Leghorn (L33) layer chickens of 39 weeks of age and average live weight of 1.8 ± 0.04 kg was carried out in a completely randomized design to evaluate the effects of vitamins C and E on erythrocyte parameters of layers during natural summer conditions. Birds were allotted to 4 treatments containing 0, 150 mg vitamin C, 150 mg vitamin E, and 150 mg vitamin C plus 150 mg vitamin E/kg feed. Each treatment was replicated four times. The exposure of layers to 31±3 °C and 33±0 °C ambient temperature and 84.6% and 81.5% relative humidity, inside and outside the experimental pen, during the study period caused an increase in temperature humidity index 15.5 above the threshold value of 70 established for this species. Total erythrocytes counts were not affected by treatment. However, hematocrit and hemoglobin were significantly (p<0.001) different in vitamin-C and E treated groups, individually or in combination, as compared to the control birds. Also, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration of the birds fed vitamins C or E, or vitamins C+E were significantly (p<0.001) higher than those in control group. The results of the present study showed that the dietary supplementation of vitamin C and E, particularly as a combination, alleviated the counterproductive effects of high ambient temperature and humidity on the birds.