Effects of complex direct-fed microbial supplementation in different basal diets on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding and noxious gas emission in growing pigs

Abstract Text: Antibiotics which are used as feed additives can lead to the transmission and proliferation of resistant bacteria via food chain. Alternatives of antibiotics have focused on probiotics. Additionally, it is well suggested that the diet composition could influence the efficacy of probiotics. Hence, the objective of this study was to determine the effects of complex direct-fed microbial (Bacillus subtilis 1.0 × 10⁷ cfu/g; Saccharomyces cerevisae 1.0 × 10⁷ cfu/g) supplementation in different basal diets on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding and noxious gas emission in growing pigs. A total of 100 crossbred pigs [(Landrace × Yorkshire) × Duroc] with an average initial BW of 24.88 ± 1.57 kg were used in a 6-wk experiment. Pigs were randomly allotted to a 2 × 2 factorial arrangement with 2 different basal diets (non palm kernel expellers (PKE) containing diet vs 10% PKE containing diet) and 0 or 0.3% complex probiotics according to their BW (5 replicate pens, 5 pigs per pen). All experimental data were analyzed using the GLM procedure of SAS as a completely randomized 2 × 2 factorial design (SAS Inst. Inc., Cary, NC, USA), the pen was served as the experimental unit. At the end of experiment, pigs fed non-PKE containing diet increased final BW, overall ADG and G:F (P < 0.01), and decreased the fecal total mercaptans concentrations (P < 0.05). Moreover, the final BW (P < 0.05) and overall ADG (P < 0.05), as well as apparent total tract digestibility (ATTD) of dry matter (P < 0.05) and energy (P < 0.01), were improved when pigs fed the probiotic supplement. Dietary supplementation with probiotic increased fecal Lactobacillus concentrations and decreased E. coil concentrations (P < 0.01), respectively. The fecal NH₃, total mercaptans and H₂S emissions were reduced by feeding diets containing probiotic (P < 0.01). Additionally, interactive effects of different diets and probiotics were also observed on final BW, overall ADG and G:F (P < 0.01). In conclusion, B. subtilis and S. cerevisae complex could provide positive effect on growth performance, nutrient digestibility, intestinal microflora, and fecal gas emissions in growing pigs. Moreover, the use of probiotics in non-PKE containing diet was more favorable than in PKE containing diet.

Keywords: probiotics, different basal diets, growing pig