Direct fed microbials (DFM) are defined as live microorganisms that offer a health benefit for the host when administered in appropriate and regular quantities. Bacillus-based DFM are aerobic, spore-forming bacteria that may enhance the host animal’s immune response and improve growth performance in weanling pigs. Bacillus spp. also produce extracellular enzymes that may enhance digestibility and absorption of nutrients.

An experiment was, therefore, conducted to test the hypothesis that two DFM containing Bacillus strains (provided by Chr. Hansen A/S, Horsholm, Denmark) improve the apparent ileal digestibility (AID) of AA, CP, and GE, the apparent total tract digestibility (ATTD) of CP and GE, and hindgut digestibility of CP and GE when fed to growing pigs.

Walsh, M. C., L. Payling, I. H. Kim, and H. H. Stein. 2017. Effects of a multistrain Bacillus spp. direct-fed microbial and protease combination at different doses on apparent ileal and total tract digestibility of nutrients in growing pigs fed corn–soybean meal–based diets – A combined analysis of two studies. J. Anim. Sci. 95(Suppl. 5):141 (Abstr.) Link to abstract (.pdf)

Jaworski, N. W., M. C. Walsh, and H. H. Stein. 2016. Effect of a 3-Strain Bacillus-based direct-fed microbial on relative tissue gene expression in nursery and finishing pigs fed low- or high-fiber diets. J. Anim. Sci. 94(Suppl. 2):83 (Abstr.) Link to abstract (.pdf)

Increasing the inclusion of dietary fiber in nursery pig diets may stimulate beneficial gut microbiota and reduce post-weaning diarrhea. However, the digestibility of nutrients and energy is decreased in high fiber diets. Nursery pigs fed diets high in fiber have been shown to have reduced ADFI and G:F.

Bacillus-based direct-fed microbials (DFM) secrete a large amount and a wide variety of fiber degrading enzymes. It is thought that feeding DFM may offset some of the negative effects of  a high fiber diet. Therefore, an experiment was conducted to test the hypothesis that addition of a Bacillus-based DFM will increase fermentation of dietary fiber and improve growth performance when fed to nursery pigs.

Jaworski, N. W., A. Owusu-Asiedu, A. Awati, A. Thomas, and H. H. Stein. 2015. Effect of a 3-strain Bacillus-based direct-fed microbial on growth performance, volatile fatty acid production, carcass characteristics, and gastrointestinal tract weights in growing-finishing pigs fed low or high fiber diets. J. Anim. Sci. 93(Suppl. s3):856 (Abstr.) Link to abstract (.pdf)

Jaworski, N. W., A. Owusu-Asiedu, A. A. Awati, and H. H. Stein. 2014. Effect of Bacillus spp. direct-fed microbials on fecal VFA concentrations, growth performance, and carcass characteristics of growing-finishing pigs. J. Anim. Sci. 92(Suppl. 2):56 (Abstr.) Link to abstract (.pdf)