Can soluble dietary fiber reduce the need for antimicrobials in nursery diets?

Increased soluble fiber in pig diets shows promise as an alternative for growth-promoting antimicrobials in nursery diets, according to Eric Burrough, DVM, Veterinary Diagnostic Lab, Iowa State University.¹

The benefits of dietary fiber on gastrointestinal microorganisms are well known in humans. To see if the same benefits apply to pigs, Burrough reviewed many feed studies monitoring the effects of additional fiber in pig diets.

Overall, he noted that adding certain soluble fibers helps increase beneficial bacteria (lactobacilli and bifidobacteria) in pig guts while reducing pathogens.

Nursery-pig benefits

Burrough, who presented his work at the 2017 American Association of Swine Veterinarians conference, looked at recent studies examining how different diets affected the incidence of swine dysentery (SD) when nursery pigs were inoculated with the causative bacteria.

The diets discussed included a highly digestible rice-based diet, a diet with 30% distillers’ dried grains with solubles (DDGS), a diet high in inulin and a standard corn-soy diet.

Pigs fed the rice-based diet had reduced shedding of spirochetes and were protected against SD. Pigs fed the diet high in inulin showed reduced expression of SD. However, pigs fed diets with 30% DDGS shed spirochetes and developed SD faster than pigs fed the corn-soy diet.

Burrough also reviewed studies using probiotics, prebiotics and synbiotics to reduce antibiotics use in nursery-pig diets. The controlled experiments did offer promising results but have not been duplicated in the field due to challenges with commercial animal-husbandry practices and difficulties measuring the impact on the gut, he said.

Instead, based on previous studies, increased soluble fiber in pig diets “has repeatedly shown promise in modulating the colonic microbiota of pigs to favor beneficial bacteria at the expense of specific pathogens,” Burrough added.

¹Burrough ER. The impact of feed on the pig intestinal microbiome, Feed: Commanding New Focus. 48^th American Association of Swine Veterinarians’ Annual Meeting. 2017;19.