Effect of Bacillus subtilis supplementation in diets on growth performance, carcass quality, gut microflora and immune response of broiler chickensOriginal Title (non-English) A tap Bacillus subtilisszel torteno kiegeszitesenek hatasa a brojlercsirke novekedesere, husminosegere, a bel mikroflorajara es az immunvalasz mertekere [Hungarian]

摘要

This trial was conducted to study the effects of different Bacillus subtilis concentrations on growth performance, carcass quality, immune response and gut microflora of broiler chickens. There were 5 treatment groups: control (A), with no added B. subtilis supplementation and 4 treatment groups, which received feed supplemented with different B. subtilis concentration in the premix (B: 7.27 x 10(8) cfu/g; C: 7.27 x 10(9) cfu/g; D: 7.27 x 10(10) cfu/g and E: 7.27 x 10(11) cfu/g). In the trial 1620 Ross 308 broilers participated. The weight of broiler chickens in all groups given feed supplemented with B. subtilis was significantly higher (P<0.05), independently its concentration than that of the control chickens (B: 2406.9 g, C: 2438.5 g, D: 2398.7 g, E: 2419.5 g vs A: 2271.9 g). The feed conversion rate of each group fed on B. subtilis supplemented diet was better (P<0.05) than that of the control group (1.86 vs 1.94). The groups given B. subtilis supplementation produced relatively bigger breasts, smaller carcasses and thighs compared to the control group. B. subtilis supplementation did not alter the thickness and morphological appearance of the different layers (mucosa, muscle and serosa), the length of the villi and the depth of the crypts of Lieberkuhn. The degree of diffuse lymphohistiocytic infiltration and the number of solitary lymphoid follicles in the mucosa increased in accordance with the B. subtilis concentration of the feed. The birds from the groups fed on B. subtilis supplemented diets had significantly increased antibody responses to vaccination against Newcastle disease virus. The higher inclusion rate of B. subtilis did not increase Lactobacillus concentrations in the ileum or in the caecum, but decreased significantly the intestinal E. coil population. On the basis of the results, the smallest dose of B. subtilis supplementation given by the authors can be recommended for the use of practice because it significantly improves the efficiency of broiler production, has a positive effect on immune system, and is the most economic.