Histological and immunohistochemical features of gastrointestinal tract, alveolar macrophages and blood leukocytes of pigs fed with polyphenols

In the last years, great importance has been given to the anti-oxidant and anti-pathogens effects of polyphenols. In this report, we describe the effect of polyphenols derived from wastewater olive-oil production on blood leukocytes and alveolar macrophages primary cell cultures and on gastrointestinal tract of pigs. Pigs were fed with the addition of polyphenols to standard diet for three months until their regular slaughter. Superoxide anion assay was performed on leukocytes, extracted and cultured from peripheral blood, and alveolar macrophages, isolated and cultured following Brockmeier method. In addition, histological samples of gastrointestinal tract (from stomach to rectum) were analyzed by ematoxylin-eosin staining (to evaluate the height and length of mucosal epithelium and the wideness of leukocytes infiltrate) and immunohistochemical method (using antibody against cyclooxygenase-2/COX-2). The results obtained show low levels of superoxide anion in the samples collected from the experimental group with respect to the control, while no significant differences were observed in the gastrointestinal tract, with the exception of leukocytes infiltrate in caecum-colon samples of treated animals. Finally, COX-2 immunopositive cells were found exclusively in the samples collected from control group. We suggest that the addition of polyphenols to standard diet reduces the presence of superoxide anion in pig peripheral leukocytes and alveolar macrophages and improves the immune response in the adult pig gut. In conclusion, we propose a possible re-use of this agri-food industry waste, otherwise highly polluting, as feed additives for farm animals.