Effect of Dietary Oregano (Lippia origanoides) and Clover (Eugenia caryophillata) Essential Oils' Formulations on Intestinal Health and Performance of Pigs.

The incorporation of natural essential oils to the pigs' diet in intensive production systems is a potential tool to improve gut health and prevent infections without using antibiotics. Nevertheless, different products, even containing the same compounds, coming from the same botanical species, may exert dissimilar biological effects due differences in the technological processes by which they are produced and preserved. For this reason, suitability of a given product based on natural extracts, intended for swine production must be thoroughly evaluated. In the present study, we assessed the effects of three additives containing oregano (Lippia origanoides) essential oil, alone or in combination with clover (Eugenia caryophillata) essential oil, with or without being microencapsulated, on gastrointestinal health and on some performance parameters in a commercial pig production farm. Recently weaned piglets were randomly divided in four groups, and basal diet or essential oil-supplemented diet (OCE; MOCE; MOE) was randomly assigned to each of the groups from weaning to finishing. Blood samples were collected at pre-established days after weaning. Intestinal sampling took place at 42 and 72 days of age. Pigs consuming the supplemented diets showed higher intestinal metabolic activity during the post-weaning period, decreasing the impact of weaning stress on enterocytes' metabolism. Intestinal barrier function was not affected in pigs consuming microencapsulated products. All treated groups showed improved intestinal architecture, increased digestive enzymes activity and caecal VFA concentrations. The incorporation of the dietary essential oils products brought beneficial effects on gastrointestinal health that were reflected in improved performance parameters.

Ex vivo penetration of fosfomycin into healthy and Lawsonia intracellularis-colonized swine intestinal mucosa.

Fosfomycin (FOS) is an antibiotic used, mostly in Latin America, for the treatment of lung and enteric infections of pigs. Intracellular fluids of enterocytes can act as biophase for Lawsonia intracellularis, the causative agent of porcine proliferative enteropathy (PPE). The aim of this study was to determine whether the presence of L. intracellularis in the enterocytes modifies FOS penetration. Eight healthy pigs in growth-finishing stage were used to produce healthy (group A) and L. intracellularis-colonized (group B) intestinal explants. For both groups, treatment consisted of a 580 µg/ml concentration of calcium FOS, which was added to each explant (0.5-6 hr). For group B, the Enterisol Ileitis® vaccine was used as source of the micro-organism. Previously to the assay, the time necessary for L. intracellularis to colonize the enterocytes was defined. Also, a PCR protocol was optimized to determine the presence of the pathogen in the explants. There were nonstatistical differences for the penetration of the antibiotic into healthy and L. intracellularis-colonized enterocytes. MIC90 of FOS for L. intracellularis is unknown; nevertheless, MIC90 of various antibiotics ranges between 0.125 and 128 µg/ml. FOS reaches inside the enterocyte concentrations which surpass the MICs90 of other antibiotics that also act by the inhibition of cell wall synthesis; however, further studies should be carried out to determine fosfomycin MIC90 for L. intracellularis to discern the usefulness of this antibiotic in the treatment of PPE.