Abstract
The objectives of this investigation were to evaluate the influence of dietary supplementation with different levels of Bacillus toyonensis ATCC 55050 (BT), Bifidobacterium bifidum ATCC 29521 (BB), and a combination of half the dose of BT and BB on the productive performance, carcass characteristics, physiological parameters, and gut microbiota of laying Japanese quails (Coturnix coturnix japonica). A total of 144 laying quail chicks (56 days old, Japanese quail) were assigned to four experimental groups in a fully randomized design experiment for 12 weeks. Twelve replicates, each consisting of two female and one male bird, were created for each group. The control group of birds received a corn-soybean basal diet from 56 to 140 days of the trial. In contrast, the groups receiving probiotics were given the same control diet supplemented with 0.1% Bacillus toyonensis (BT), 0.1% Bifidobacterium bifidum (BB), or a combination of 0.05% Bacillus toyonensis plus 0.05% Bifidobacterium bifidum (BT+BB). There was a significant enhancement (P<0.05) in performance traits during different weeks of age as a result of the treatments with Bacillus toyonensis (BT), Bifidobacterium bifidum (BB), and the combination of both (BT+BB), except for live body weight. The results demonstrated a significant influence (P<0.05) of various probiotic treatments on fertility (Fer) and hatchability (Ha) percentages. BT+BB showed the highest fertility (98.57%) and total embryonic mortality (15.95%) compared to the other treatments. Also, the digestive enzymes activity was significantly (P<0.05) enhanced by BT and BT+BB treatments; besides, the BT+BB treatment showed higher levels of all antioxidant traits. In summary, the addition of Bacillus toyonensis (BT), Bifidobacterium bifidum (BB), and their combination (BT+BB) to the diet of laying quails significantly improved performance, blood traits, and decreased total bacterial counts, coliform levels, total fungi, and the cecal microflora.