Effects of dietary probiotic ( Bacillus subtilis ) supplementation on productive performance, immune response and egg quality characteristics in laying hens under high ambient temperature

摘要

Abstract A two level factorial experiment (3?×?3) was designed to evaluate the effect of dietary inclusion level of probiotic and breed on productive performance, immune status and egg quality characteristics in laying hens reared under high ambient temperature. A total of 216, 32-week-old laying hens representing three different breeds (White Leghorn, Saudi black and Saudi brown) were randomly assigned to three dietary treatments (0, 200 and 400?g/t feed) in a 90-d experiment. The current results indicated that the inclusion of probiotics in layer diets did not appear to cause any adverse effects on egg production traits compared with non-treated hens. Dietary supplementation with probiotics at 400?ppm level significantly (p?p?