332 Original Paper Czech J. Anim. Sci., 57, 2012 (7): 332–343 Efect of dietary natural supplements on immune response and mineral bioavailability in piglets after weaning I. Taranu 1 , D.E. Marin 1 , A. Untea 1,2 , P. Janczyk 3,4 , M. Motiu 1 , R.D. Criste 1 , W.B. Souffrant 3,4 1 INCDBNA, National Development Institute for Biology and Animal Nutrition, Balotesti, Romania 2 Department of Analytical Chemistry, University of Bucharest, Bucharest, Romania 3 Leibnitz Institute for Farm Animal Biology and Unit Genetics & Biometry, Dummerstorf, Germany 4 Chair for Nutrition Physiology and Animal Nutrition, University of Rostock, Rostock, Germany ABSTRACT: Plants and plant extracts (PPEs) have gained increasing interest as feed additives and possible replacing antibiotics for pig productions. The effects of dietary Chlorella vulgaris (1%), sodium alginate (0.1%), inulin (1.5%), and a mixture of essential oils (0.04%) supplements on immune response, and bioavail- ability of some micronutrients (iron − Fe, copper − Cu, manganese − Mn, and zinc − Zn) were investigated in weaned piglets in this study. The results showed that the concentration of IgG was increased in the plasma of pigs fed the PPEs supplemented diets being significantly higher (P < 0.05) in the case of dietary sodium alginate supplementation in comparison to the control (6.00 vs. 4.03 mg/ml). In liver, PPEs, especially inulin and essential oils, were able to modulate the level of cytokine production and mineral retention, resulting in higher liver concentration of IL-1β (125.4 and 88.9%), IL-8 (136.9 and 61.3%), TNF-a (296.6 and 121.6%), and IFN-γ (51.2 and 107.28%), Cu (71.31 ppm), and Fe (192.56 ppm) in comparison to the control. The results of this experiment indicate that natural supplements investigated herein, especially inulin, essential oils, and sodium alginate had the ability to potentiate both the immune function and mineral retention during the initial post weaning period. Keywords: pig; natural supplements; minerals; immune response Since the ban of the in-feed antibiotics in the European Union, plants and plant extracts (PPEs) have gained increasing interest as possible alter- natives to the in-feed antibiotics, and also as feed additives for pig production (Van Nevel et al., 2005; Windisch et al., 2008). In many studies health ben- efits obtained via their immunostimulatory proper- ties were observed after the use of different PPEs in animal diets. For example, thymol and carvacrol, active components of plant essential oils are able to increase the percentage of CD4 + , CD8 + , MHC class II, and non-T/non-B cells in peripheral blood, and CD4+ CD8+ double-positive T lymphocytes in peripheral blood and mesenteric lymph nodes in growth-retarded, low-weight growing-finishing pigs (Walter and Bilkei, 2004). Thymol used alone enhances total IgA and IgM serum levels, and ex- hibits some local anti-inflammatory properties, as indicated by reduction of TNF-a mRNA in the stomach of post-weaned pigs (Trevisi et al., 2007). Plants from the Echinacea family are also known to modulate immune functions. Pharmacological data inferred that Echinacea preparations stimulate the innate immune system and increase the resistance Supported by funds from the European project “Feed for Pig Health” (FOOD-CT-2004-506144) and the project “PNII” 2008–2011 granted by the Romanian Ministry of Research and Technology.