Effect of dietary benzoic acid and supplemental enzymes on fiber-fermenting taxa and metabolites in the cecum of weaned pigs

Inclusion of enzymes and organic acids in pig diets is an important strategy supporting decreased antibiotic usage in pork production. However, limited knowledge exists about how these additives impact intestinal microbes and their metabolites.

Methods: The objective of this study was to examine the effects of benzoic acid and enzymes on gut microbiota and metabolome of weaned pigs. 160 pigs were assigned to one of four diets 7 days after weaning: a control diet or the addition of 0.5% benzoic acid, 0.045% dietary enzymes (phytase, β-glucanase, xylanase, and α-amylase), or both and fed ad libitum for 21 to 22 d. Individual growth performance and group diarrhea incidence data were collected throughout the experimental period. In addition, cecal digesta samples were collected at the end of the experimental period from 40 piglets (10 per group) and evaluated for differences using 16S rRNA sequencing and two-dimensional gas chromatography and time-of-flight mass spectrometry (GCxGC-TOFMS).

Results: Pigs fed the benzoic acid diet had a greater daily feed intake and gained more weight over the experimental period than pigs fed the control diet and no differences in growth or feed intake for the other diets. A decrease of 20% in pen-level diarrhea incidence from days 8 to 14 in pigs fed both benzoic acid and enzymes compared to the control diet. Analysis of cecal microbiota diversity revealed that benzoic acid altered microbiota composition (Unweighted Unifrac) and decreased α-diversity (Shannon; Faith’s Phylogenetic Diversity). Dietary enzymes increased fiber-fermenting bacterial taxa such as Prevotellaceae. Two-step feature selection identified 17 cecal metabolites that differed among diets, including increased microbial cross-feeding product 1,2-propanediol in pigs-fed benzoic acid-containing diets.

Conclusion: Dietary benzoic acid and enzymes affected the gut microbiota and metabolome of weaned pigs and may support the health and resolution of postweaning diarrhea.

Diether NE, Nam SL, Fouhse J, Le Thanh BV, Stothard P, Zijlstra RT, Harynuk J, de la Mata P, Willing BP. Dietary benzoic acid and supplemental enzymes alter fiber-fermenting taxa and metabolites in the cecum of weaned pigs. Journal of Animal Science. 2022; 100(11): skac324. https://doi.org/10.1093%2Fjas%2Fskac324