Lactulose increases bacterial diversity and modulates the swine faecal microbiome as revealed by 454-pyrosequencing

Lactulose drives a reversible reduction and qualitative modulation of the faecal microbiota diversity in healthy dogs

Hepatic encephalopathy is a frequent and debilitating complication of liver disorders. Lactulose is an established and reasonably effective treatment, yet with incompletely understood mechanisms of action. The aims of this study were to examine how the faecal microbiota composition changed before, during and after lactulose treatment in a large animal model. Healthy, privately owned dogs (n = 18) completed a prospective cohort study. Faecal samples were collected weekly, while the subjects were either on their usual diet (week 1), or a standardised diet (weeks 2–9), with added oral lactulose in weeks 6–7. DNA extraction and 16S rRNA gene sequencing were undertaken. Faecal samples from week 7 had a significantly lower microbiota richness/diversity, based on observed operational taxonomic units, Shannon/Chao1 indexes and Pielou’s Evenness. Beta diversity based on UniFrac distances was significantly different in week 7 compared to weeks 1, 5 and 9. At the phylum level, week 7 was associated with a significant increase of Firmicutes and Actinobacteria, and a decrease of Bacteroidetes and Fusobacteria, when compared to weeks 5 and 9. In summary, we have shown that lactulose induces a reversible qualitative and quantitative change of the faecal microbiota, which may explain its clinical efficacy in the management of hepatic encephalopathy.

Effects of a Lactulose-Rich Diet on Fecal Microbiome and Metabolome in Pregnant Mice

Lactulose, a safe and beneficial molecule, can be used in food as a prebiotic and as an osmotic laxative during pregnancy. This work evaluated the effects of dietary lactulose on the gut microenvironment of pregnant mice using the fecal microbiota and metabolomic profiling. After 2 weeks of feeding, the Bifidobacterium and Bacteroides abundances in the mouse feces were significantly increased in the LAC-high (the diet supplemented with 15% lactulose) group. A total of 15 metabolites, including 1-monoolein, glucose-6-phosphate, and short-chain fatty acids, were increased significantly in the LAC-high group. The serum glucose and total cholesterol concentrations were significantly decreased, while the progesterone level was significantly increased in the lactulose-fed mice. In the LAC-high group, the colonic pH and intestinal permeability were decreased, while the immunoglobulins in the colonic epithelial cells and the small intestinal absorption capacity were significantly increased. These findings indicated that lactulose supplementation benefitted pregnancy performance in mice.

Pyrosequencing-based analysis of the complex microbiota located in the gastrointestinal tracts of growing-finishing pigs

The commensal gut microbial communities play an important role in the health and production efficiency of growing-finishing pigs. This study aimed to analyse the composition and diversity of the microbiota in the gastrointestinal tract sections (stomach, duodenum, jejunum, ileum, caecum, colon and rectum) of growing-finishing pigs. This analysis was assessed using 454 pyrosequencing targeting the V3–V6 region of the 16S rRNA gene. Samples were collected from 20, healthy pigs aged 24 weeks and weighing 115.9 ± 5.4 kg. The dominant bacterial phyla in the various gastrointestinal tract sections were Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria. At the genus level, Prevotella, unclassified Lachnospiraceae, Ruminococcus, unclassified Ruminococcaceae and Oscillospira were more abundant in the large intestine than in the stomach and the small intestine. Unclassified Peptostreptococcaceae and Corynebacterium were more abundant in the small intestine than in the stomach and the large intestine. Shuttleworthia, unclassified Veillonellaceae and Mitsuokella were more abundant in the stomach than in the small and large intestines. At the species level, M. el.s.d.enii and M. multacida were predominant in the stomach. In addition, P. stercorea, P. copri, C. butyricum, R. flavefaciens and R. bromii were significantly more abundant in the large intestine than in the stomach and the small intestine. B. pseudolongum and B. thermacidophilum were significantly more abundant in the small intestine than in the stomach and the large intestine. Principal coordinates analysis showed that the overall composition of the pig gastrointestinal microbiota could be clustered into three groups: stomach, small intestine (duodenum, jejunum and ileum) and large intestine (caecum, colon and rectum). Venn diagrams illustrated the distribution of shared and specific operational taxonomic units among the various gastrointestinal tract sections.

Intestinal Microbiota Ecological Response to Oral Administrations of Hydrogen-Rich Water and Lactulose in Female Piglets Fed a Fusarium Toxin-Contaminated Diet

The objective of the current experiment was to explore the intestinal microbiota ecological response to oral administrations of hydrogen-rich water (HRW) and lactulose (LAC) in female piglets fed a Fusarium mycotoxin-contaminated diet. A total of 24 individually-housed female piglets (Landrace × large × white; initial average body weight, 7.25 ± 1.02 kg) were randomly assigned to receive four treatments (six pigs/treatment): uncontaminated basal diet (negative control, NC), mycotoxin-contaminated diet (MC), MC diet + HRW (MC + HRW), and MC diet + LAC (MC + LAC) for 25 days. Hydrogen levels in the mucosa of different intestine segments were measured at the end of the experiment. Fecal scoring and diarrhea rate were recorded every day during the whole period of the experiment. Short-chain fatty acids (SCFAs) profiles in the digesta of the foregut and hindgut samples were assayed. The populations of selected bacteria and denaturing gradient gel electrophoresis (DGGE) profiles of total bacteria and methanogenic Archaea were also evaluated. Results showed that Fusarium mycotoxins not only reduced the hydrogen levels in the caecum but also shifted the SCFAs production, and populations and communities of microbiota. HRW treatment increased the hydrogen levels of the stomach and duodenum. HRW and LAC groups also had higher colon and caecum hydrogen levels than the MC group. Both HRW and LAC protected against the mycotoxin-contaminated diet-induced higher diarrhea rate and lower SCFA production in the digesta of the colon and caecum. In addition, the DGGE profile results indicated that HRW and LAC might shift the pathways of hydrogen-utilization bacteria, and change the diversity of intestine microbiota. Moreover, HRW and LAC administrations reversed the mycotoxin-contaminated diet-induced changing of the populations of Escherichia coli (E. coli) and Bifidobacterium in ileum digesta and hydrogen-utilizing bacteria in colon digesta.

Effect of lactulose intervention on gut microbiota and short chain fatty acid composition of C57BL/6J mice

Gut microbiota have strong connections with health. Lactulose has been shown to regulate gut microbiota and benefit host health. In this study, the effect of short‐term (3 week) intervention of lactulose on gut microbiota was investigated. Gut microbiota were detected from mouse feces by 16S rRNA high‐throughput sequencing, and short chain fatty acids (SCFAs) were detected by gas chromatography‐mass spectrometry (GC‐MS). Lactulose intervention enhanced the α‐diversity of the gut microbiota; increased the abundance of hydrogen‐producing bacteria Prevotellaceae and Rikenellaceae, probiotics Bifidobacteriaceae and Lactobacillaceae, and mucin‐degrading bacteria Akkermansia and Helicobacter; decreased the abundance of harmful bacteria Desulfovibrionaceae and branched‐chain SCFAs (BCFAs). These results suggest that lactulose intervention effectively increased the diversity and improved the structure of the intestinal microbiota, which may be beneficial for host health.

Revealing the combined effects of lactulose and probiotic enterococci on the swine faecal microbiota using 454 pyrosequencing

Demand for the development of non‐antibiotic growth promoters in animal production has increased in recent years. This report compared the faecal microbiota of weaned piglets under the administration of a basal diet (CON) or that containing prebiotic lactulose (LAC), probiotic Enterococcus faecium NCIMB 11181 (PRO) or their synbiotic combination (SYN). At the phylum level, the Firmicutes to Bacteroidetes ratio increased in the treatment groups compared with the CON group, and the lowest proportion of Proteobacteria was observed in the LAC group. At the family level, Enterobacteriaceae decreased in all treatments; more than a 10‐fold reduction was observed in the LAC (0.99%) group compared with the CON group. At the genus level, the highest Oscillibacter proportion was detected in PRO, the highest Clostridium in LAC and the highest Lactobacillus in SYN; the abundance of Escherichia was lowest in the LAC group. Clustering in the discriminant analysis of principal components revealed distinct separation of the feeding groups (CON, LAC, PRO and SYN), showing different microbial compositions according to different feed additives or their combination. These results suggest that individual materials and their combination have unique actions and independent mechanisms for changes in the distal gut microbiota.