Interpretive Summary: Feed additive blends fed to nursery pigs challenged with Salmonella
By: Jackie Walling
Salmonellosis is a global human concern because it occurs at various points in pig production. An article published in the Journal of Animal Science evaluates fermented fungal products, coated butyrate (BU), and organic acids (OAs) as control strategies. Researchers evaluated mannan-rich hydrolyzed copra meal (MCM) and fermented rye (FR) with Agaricus subrufescens to control Salmonella and Escherichia coli. Efficacy was assessed to control the shedding of Salmonella enterica serovar Typhimurium with OA and BU.
In vitro and in vivo studies were performed. For in vivo, a total of 32 pigs were evaluated and split into four groups: control diet, OA.BU, OA.MCM and OA.FR. The study lasted 31 days, and pigs were challenged with 1 mL of S. Typh for seven days.
In vitro studies showed that MCM and FR had a high binding affinity for S. Typh and S. Ent, but not for enterotoxigenic Escherichia coli F4 or F18. For in vivo studies, OA.MCM and OA.FR pigs had lower shedding counts for S. Typh. OA.FR pigs tended to be heavier than the other groups, but rectal temperatures did not differ. Diarrhea incidence tended to be lower for OA.FR pigs.
In vitro and in vivo results were in agreement. Binding affinity was seen in vitro. A mode of blocking adhesion may be how some of the feed additives work in preventing colonization of Salmonella strains; however, binding affinity may not reduce the risk of pathogenic adhesion. Susceptibility to disease should be determined in vivo with bacterial shedding. Less shedding insinuates less infection.
Overall, when coupled to OA, FR and MCM showed binding affinity to both Salmonella strains. Shedding for S. Typh was reduced with both. BU seemed to have little effects on pigs. FR with OA showed the most positive results though more research needs to be done to understand its mode of action.
For the full article, visit the Journal of Animal Science.