Serum folate, cobalamin, homocysteine and methylmalonic acid concentrations in pigs with acute, chronic or subclinical Lawsonia intracellularis infection

- Lawsonia intracellularis causes porcine proliferative enteropathy, which has three forms.
- Acute (proliferative hemorrhagic enteropathy, PHE), chronic (porcine intestinal adenomatosis, PIA) and subclinical.
- Pigs with PHE or PIA had lower serum folate and higher serum homocysteine concentrations than pigs with subclinical infection.
- Pigs with PIA had lower serum cobalamin concentrations than pigs with PHE and subclinical L. intracellularis infection.
- Pigs with subclinical L. intracellularis infection had higher serum MMA concentrations than pigs with PIA and PHE.

Lawsonia intracellularis is the causative agent of porcine proliferative enteropathy. The clinical presentation can be acute (i.e. proliferative hemorrhagic enteropathy, PHE), chronic (i.e. porcine intestinal adenomatosis, PIA) or subclinical. In humans with chronic enteropathies, low serum folate (vitamin B9) and cobalamin (vitamin B12) concentrations have been associated with increased serum concentrations of homocysteine and methylmalonic acid (MMA), which reflect the availability of both vitamins at the cellular level. The aim of this study was to evaluate serum folate, cobalamin, homocysteine and MMA concentrations in serum samples from pigs with PHE, PIA or subclinical L. intracellularis infection, and in negative controls. Serum folate, cobalamin, homocysteine and MMA concentrations differed significantly among pigs in the PHE, PIA, subclinical and negative control groups. Serum folate concentrations in the PHE and PIA groups were lower than in the subclinical and negative control groups, while serum cobalamin concentrations were lower in the PIA group than in other groups. Serum concentrations of homocysteine were higher in the PHE, PIA and subclinical groups than in the negative control group. Serum concentrations of MMA were higher in the subclinical and PIA groups than in the control group. These data suggest that pigs infected with L. intracellularis have altered serum cobalamin, folate, homocysteine and MMA concentrations.