Studies on the health impact of Agrimonia procera in piglets

BACKGROUND: The weaning period is critical for stress-related diseases and infections. Currently, large amounts of therapeutic antimicrobials are used to treat infections in the livestock production, especially in piglets. Phytogenic feed additives could provide a useful alternative. We hypothesize, that components in agrimonia species which have been used successfully in humans to treat gastrointestinal infections could also improve the health of piglets. We investigated the effects of Agrimonia procera (AP) on the growth performance of piglets and cytokine expression in isolated porcine peripheral blood mononuclear cells (PBMC). RESULTS: Here we show that piglets that received a diet with 0.56 g/kg AP for 6 weeks tended to ingest more food (+5.1%; P < 0.10), and were characterized by a higher nitrogen retention (+9.6%, P < 0.05) than the control group without AP treatment. Data from a second experiment reveal that piglets fed a diet with 0.87 g/kg AP for 6 weeks had an improved food conversion ratio (1.46 ± 0.04) compared to those that received none (1.54 ± 0.08) or 8.7 g/kg AP (1.60 ± 0.08) with their diets (P < 0.001). However, the food intake, daily weight gain and dry matter of feces were not affected by the AP treatment. Treatment of PBMC for 1 and 6 h with AP extract (APE) reduced the mRNA abundance of tumor necrosis factor (TNF)α in cells challenged with lipopolysaccharides (LPS) but not in cells without LPS stimulation (P < 0.05). The lower mRNA expression of TNFα was accompanied by a trend towards a lower release of TNFα from these cells (P = 0.067). After the treatment of PBMC with APE for 6 h, the relative mRNA concentration of interleukin (IL)-1β declined (P < 0.05), whereas that of IL-10 remained unchanged. Treatment of LPS-challenged PBMC for 20 h with varying concentrations of APE did not reveal any effect on cytokine expression and TNFα release. CONCLUSIONS: The results indicate that low dosages of AP may improve the growth performance of piglets and seem to exert antiinflammatory effects in porcine immune cells challenged with LPS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-014-0210-y) contains supplementary material, which is available to authorized users.