Effect of oral cobalamin supplementation on fecal Lawsonia intracellularis genome fragments in vaccinated and non-vaccinated weaned pigs

Porcine proliferative enteropathy (PPE), also known as ileitis, is caused by the obligate intracellular bacterium Lawsonia intracellularis. Pigs with subclinical PPE have no specific clinical signs, but their production performance is decreased during the growth and fattening period due to a reduced nutrient absorption by immature enterocytes in the small intestine. The majority of cobalamin (vitamin B12), which plays an important role in amino acid metabolism and nucleic acid synthesis, is absorbed at the ileum. Therefore, we evaluated if oral supplementation of cobalamin affects the performance in weaned pigs that are either vaccinated or not against Lawsonia intracellularis.

Pigs from a selected farm with a confirmed Lawsonia intracellularis-infection were included in the study. Twelve pigs each were randomly assigned to 5 different groups (vaccinated [vacc.]/non-supplemented [non-suppl.], vacc./suppl., non-vacc./non-suppl., non-vacc./suppl., and tylosin [non-vacc./non-suppl.]). Corresponding pigs were administered an avirulent live Lawsonia intracellularis vaccine, received tylosin (4.5 mg/kg body weight) for the whole study period or cobalamin orally (0.2 mg/kg feed) from day 8 to 21. Fecal samples were obtained from all pigs on day 0, 7, 14 and 21. Lawsonia intracellularis was tested using a quantitative fecal PCR test. An ANOVA or MANOVA model was used to compare the average daily weight gain (ADWG), oral supplementation of cobalamin and amount of fecal Lawsonia intracellularis genome fragments among the 5 groups of pigs.

Baseline body weights differed significantly among the 5 groups of pigs (p=0.017), caused by lower weight of the tylosin compared to vacc./nonsuppl. pigs. The ADWG differed significantly among the groups (p=0.006), with the lowest ADWG observed in the non-vacc./non-suppl. group compared to the remaining 4 groups with a statistical significance of p< 0.05 for all except for the non-vacc./suppl. pigs. Levels of fecal Lawsonia intracellularis genome fragments differed significantly between the non-vacc./non.suppl. (highest), vacc./non-suppl. (increased during the trial) and tylosin (lowest) group (p< 0.001). Genome fragments of fecal Lawsonia intracellularis increased faster in vacc./suppl. pigs compared to vacc./non-suppl. pigs (p=0.001) but no difference between non-vaccinated groups (p> 0.05).

Cobalamin supplementation over 2 weeks affected fecal Lawsonia intracellularis genome fragments in vaccinated but not in non-vaccinated groups of weaned pigs. Whether supplementation of cobalamin over a longer time-period affects the production performance in non-vaccinated weaned pigs warrants further investigation.

Disclosure of Interest: N. Grützner Conflict with: Spezko - Research Fellowship, A. Luehrs: None Declared, E. grosse Beilage: None Declared, H. Nathues: None Declared.