Lactic Acid Treatment of Cereals and Dietary Phytase Modified Fecal Microbiome Composition Without Affecting Expression of Virulence Factor Genes in Growing Pigs

Abstract

Besides the major nutrients, phosphorus (P) is an essential mineral for both the host animal and the porcine gut microbiota. Different strategies including phytase supplementation and more recently lactic acid (LA) are used to enhance the P availability from cereals in pig diets; however, their impact on the gut microbiota has been rarely related to fecal shedding of opportunistic pathogens. The present study investigated the effect of phytase supplementation and the treatment of dietary cereals with 2.5% LA on the fecal microbiome composition of metabolic active bacteria and expression of virulence factor genes of enterotoxigenic Escherichia coli and Clostridium perfringens in growing pigs. Phytase supplementation reduced the fecal abundance of the most abundant Lactobacillaceae family, whereas the LA-treatment of cereals had a stronger impact on the bacterial community, reducing amylolytic, pullulanolytic and hemicellulolytic Lactobacillaceae, Lachnospiraceae and Ruminococcaceae as well as the fecal bacterial species richness (Chao1) and diversity (Shannon index). Mainly the family Clostridiaceae benefited from the decline in the aforementioned families, being enriched by both dietary treatments. Multigroup data integration using sparse partial least squares-discriminant analysis showed that among the most discriminative operational taxonomic units (OTU) especially two unclassified Clostridiaceae-OTUs, one Prevotella copri-like OTU and one OTU within the vadinCA11 group were associated with calcium and P levels but were negatively linked with complex carbohydrates in feces. Heat-stable toxin A (Sta) of enterotoxigenic E. coli and Stx2e of Shiga-toxin producing E. coli were expressed in feces but were similar among feeding groups. Without modifying the total bacterial gene copies and virulence factor expression of E. coli, both dietary phytase supplementation and LA-treatment of cereals drastically altered the bacterial community composition in pig feces. Results thereby allowed for the characterization of bacterial nutrient dependencies, indicating a link between fecal P availability, complex carbohydrate composition and alterations in the predominant genera.

A Novel Corn-Expressed Phytase Improves Daily Weight Gain, Protein Efficiency Ratio and Nutrients Digestibility and Alters Fecal Microbiota in Pigs Fed with Very Low Protein Diets

“…Little is known whether the beneficial effects of CEP on growth performance are mediated by factors other than the stimulatory role of phytase in nutrients digestibility and utilization. There is some evidence on the modulatory influence of microbial phytase on intestinal microbiota in pigs [ 36 , 37 ], but there is a paucity of information on whether CEP can change the composition of gut organisms and hence influence the performance of pigs. This is while the importance of gut microbiota and feed efficiency in pigs has been reported [ 65 ].…”

“…The beneficial effect of the CEP on the growth performance of pigs has been mainly attributed to improved digestibility of Ca and P [ 34 , 35 ]. There is some evidence that changes in intestinal availability of Ca and P as a result of using microbial phytase can affect the activity of the intestinal microbiota in pigs [ 36 , 37 ]; however, little is known whether dietary supplementation of CEP influences the performance of pigs through changes in fecal microbiota. Further, the effect of CEP on bone mineral density and content and blood metabolites associated with Ca and P metabolism is not known.…”

The fecal microbiota evolves differently in piglets experimentally infected with Cystoisospora suis that are treated with toltrazuril

“…Genomic DNA was extracted from fecal samples as described previously [70]. Then, the V3-V4 region of the 16S ribosomal RNA was amplified and sequenced [71]. Amplicon sequencing was performed on an Illumina MiSeq sequencing platform by a commercial provider (Microsynth, Balgach, Switzerland).…”

“…Reactions including samples, negative controls and the reverse transcription controls (RT minus) were run in duplicate on each plate. Standard curves were prepared from 10-fold serial dilutions (10 7 to 10 3 molecules/µl) of the purified and quantified PCR products using genomic DNA from pig feces of the present study as described [71].…”

“…Clustering of fecal samples from the treatment groups and dol were visualized in two-dimensional nonmetric multidimensional scaling (NMDS) ordination plots obtained with the 'metaMDS' function in the vegan R package [74]. To identify the most discriminant genera which have influenced α-diversity, growth performance, fecal score and oocyst excretion in feces, multigroup supervised DIABLO N-integration networking was performed using the mixOmics R package (version 6.3.2) [75] as described previously [70,71]. Sparse partial least square regression enabled the discrimination of genera across treatment groups with the lowest possible error rate selecting 10 genera, which were associated with α-diversity, growth performance, fecal score and oocyst excretion in feces.…”