Probiotics are non-pathogenic microorganisms that are potentially important non-antibiotic alternatives. This study aimed to compare novel multi-strain and single-strain Bacillus probiotics and their respective influences on broiler chickens’ performance, gut health, litter quality, immune response, and NBN and TLR gene expression. A total of 1200 Arbor-Acres 1-day-old broiler chicks were randomly allocated into three treatments (T1 was a control, T2 was supplemented with a combined Bacillus coagulans (2 × 109 cfu/g) and Bacillus licheniformis (8 × 109 cfu/g) probiotic strains (0.2 kg/ton of feed), and T3 was supplemented with Bacillus licheniformis (3.2 × 109 cfu/g) probiotic (0.5 kg/ton of feed) with eight replicas of each. Supplementing the broiler diet with either the single-strain (T3) or the multi-strain (T2) Bacillus-based probiotic raised the overall birds’ body weight, body weight gain, feed conversion ratio, and European production efficiency factor compared to the control (T1), with a significant enhancement achieved by the multi-strain Bacillus product (P = 0.005). T2 and T3 exhibited significantly improved cholesterol, Alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase levels than the control (P ≤ 0.05). The transcript levels of both NBN and TLR genes were upregulated in the liver in the T2 and T3 groups. The T2 group experienced significant reductions in gut bacterial counts, especially for Clostridia, and recorded the lowest litter moisture and nitrogen. In conclusion, supplementing broiler diets with probiotics of multiple Bacillus strains increased production profitability by promoting bird growth, improving feed intake, enhancing gut mucosa and immune organs, and upregulating genes responsible for immunity. All these inhibit the overgrowth of enteric pathogens and sustain litter quality.

This study was carried out to evaluate the effect of supplementing diet with different garlic powder concentrations (300 and 600gm/Ton) on performance, carcass characteristics and meat quality (fat %) of Muscovy ducks exposed to different stocking densities; standard stocking density (4 birds/m 2 ) and high stocking density (8 birds/m 2 ). A total number of 180 one -day -old Muscovy ducklings were used in this experiment. Birds were randomly allocated into 18 symmetrical pens classified into 6 treatment groups (3 replicate / treatment). Groups (C, SS+G 300 , SS+G 600 ) raised on standard stocking density and fed on basal diet supplemented with (0 , 300 and 600 g. garlic powder,/ton feed ) respectively while groups (HS, HS+G 300 , HS+G 600 ) raised on high stocking density and fed on basal diet supplemented with (0 , 300 and 600 g. garlic powder/ton feed) respectively. The data of growth performance indicated that supplementation of garlic (600 gm / ton) significantly (p > 0.05) improved performance (body weight gain and FCR ) of ducks in standard stocking density (SS+G 600 ) group and high stocking density in (HS+G 600 ) group. Concerning carcass characteristic and meat quality, results indicated that, garlic supplementation reduced fat % in thigh and breast muscles. It can be concluded that, adding garlic powder to duck ration can effectively compensate the negative effects of the high stocking density in Muscovy ducks. ‫ـــــــــــــــــــــــــــــــــــــــــ‬

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