Changes in nitrosative stress biomarkers in swine intestine following dietary intervention with verbascoside

In farm animals, oxidative stress can be involved in several intestinal pathological disorders, and many antioxidant molecules, especially those of plant origin, can counteract free radicals, thus stabilizing the gut environment and enhancing health. The aim of the study was to investigate whether the use of verbascoside (VB), a polyphenol plant compound, in pig feeding could modulate oxidative and/or nitrosative stress in the gut. Eighteen male piglets (Dalland) were assigned to two groups, which were fed with either a control diet (CON) or a diet supplemented with 5 mg/kg of verbascoside (VB) for 166 days. At slaughter, duodenum and jejunum specimens were collected. Immunohistochemistry and Western blot analyses were performed on the samples to evaluate free radical adducts, including acrolein (ACR), 8-hydroxydeoxyguanosine (8-OHdg) and nitrotyrosine (NT). A KRL test was also used to assess the total blood antioxidant activity, and no difference was observed. Immunohistochemistry and Western blot showed that dietary treatment decreased the levels of nitrotyrosine in enteroendocrine cell populations(P<0.05). Characterization of the enteroendocrine cell typology was then performed, and serotonin-immunoreactive cells were revealed to be directly involved in decreasing the nitrosative stress status. This preliminary study demonstrates the important role of dietary VB in decreasing stress biomarkers in swine gut, thus highlighting a possible intervention aimed at building a large prospective for antioxidant dietary supplementation in food animal species.