Assessment of a probiotic Containing Bacillus Subtilis on the Performance and Gut Health of Laying Japanese Quails (Coturnix Coturnix Japonica)

The present study was carried out to determine the effects of the inclusion of a spore-forming probiotic (Bacillus subtilis) in laying Japanese quail diets as an alternative to growth-promoting antibiotics to help produce healthy eggs and meat. This experiment was conducted as a completely randomized design with three treatments (control, 0.05% bacitracin methylene disalicylate (BMD), or 0.1% Bacillus subtilis) of five replicates of 11 quails each. Feed intake and egg production were recorded daily on cage basis. Body weight was determined at the beginning and end of the trial (36 and 42 weeks). At the end of the experiment (42 weeks), antibodies against Newcastle disease and avian influenza, egg components, Haugh units, eggshell quality and breaking strength, blood parameters, cecal microbial population, villus length, and crypt depth were measured. The dietary inclusion of Bacillus subtilis and BMD significantly (p≤0.05) increased egg production and egg weight; however, eggshell thickness and breaking strength, Haugh units, and eggshell percentages were not affected. The dietary addition of both products significantly (p≤0.05) decreased plasma cholesterol levels and increased LDL levels, as well as antibody levels against Newcastle disease and avian influenza (p≤0.01). In birds fed Bacillus subtilis and BMD, crypt depth was reduced, but villus height and villus to crypt ratio were significantly increased (p≤0.001) compared with those fed the basal diet. Cecal coliforms, E. coli, and Salmonella counts were reduced (p≤0.01) in quails fed the diets containing Bacillus subtilis and BMD compared those quails fed the non-supplemented diet. The results of this study demonstrated that in absence of AGPs, the inclusion of a spore-forming probiotic partially improves the performance of laying quails.