Recent research from the University of Illinois is showing that a direct-fed microbial (DFM) product — Clostridium butyricum — can achieve similar growth-promoting results as feed-grade antibiotics.

“Not being able to use antibiotics, these probiotics or direct-fed microbials (DFMs) are being used more and more. We have worked with DFMs for the last 10 years and have consistently observed increased growth performance in pigs,” said University of Illinois department of animal sciences professor Hans H. Stein, a co-author of the study.

Stein and his co-authors fed five diets to pigs: a control diet with no antibiotics and no C. butyricum; a control diet with standard antibiotics added, and experimental diets with 1,250, 2,500 or 3,500 colony-forming units (CFU) per kilogram of C. butyricum added.

“Pigs had better growth performance when we added C. butyricum to the diets compared with the control diet with no antibiotic, and growth performance was the same for the experimental diets as the antibiotic control diet. These results indicate C. butyricum may be used to partly or fully restore the growth performance lost when antibiotic growth promoters are removed from diets for weanling pigs,” Stein said.

As far as potential modes of action for the DFM, Stein’s team looked at several possibilities, including changes to the pigs’ intestinal morphology.

“There was better morphology in the pigs’ intestinal tracts with the C. butyricum. Villi, the tiny ‘fingers’ lining the intestinal wall, were a little bit taller. The taller the villi, the more nutrients they can absorb, and that can mean better growth performance,” Stein said.

Although Stein didn’t examine the effects of villus height on nutrient digestibility in this study, his group has shown the effect in relation to DFMs in previous research, the announcement said.

Stein’s team also evaluated the microbial community in the gut; some DFMs encourage growth of “good bacteria,” leading to secondary benefits. While the researchers found some minor differences, they said those effects could not be attributed to the experimental diets.

The team also noted a drop-off in benefits as the inclusion rate of C. butyricum went up and concluded that a dose of 1,250 CFU/kg is sufficient to attain increased growth performance in weanling pigs.

“These DFMs, including C. butyricum, seem to have pretty consistent positive effects in diets for young pigs. I think there’s a good reason they’re being used more and more in the industry. It’s a good return on investment if you add them to the diet,” Stein said.

The article was published in the Journal of Animal Science. Co-authors include Gloria Casas, Laia Blavi, Tzu-Wen Cross, Anne Lee, Kelly Swanson and Hans Stein.

The study was supported by BASF.