No impact of a phytogenic feed additive on digestion and unspecific immune reaction in piglets

Two 35 day experiments were conducted to examine the influence of a commercial phytogenic feed additive (PFA) on nutrient digestibility and unspecific immune reaction of piglets in the post-weaning period. The PFA composition was inulin, an essential oil mix (carvacrol and thymol), chestnut meal (tannins), and cellulose powder as carrier substance. In each experiment, immediately after weaning 40 male castrated piglets were divided into four experimental groups (n = 10). Diets were based on wheat, barley, soy bean meal and fishmeal using lysine as the first limiting amino acid. In experiment 1, graded levels of the PFA were supplied (A: control; B: 0.05% PFA; C: 0.1% PFA; D: 0.15% PFA). Experiment 2 utilized equal diets with 0.1% of the PFA, but different lysine supply (A: control; B: 0.1% PFA; C: +0.35% lysine; D: 0.1% PFA + 0.35% lysine). At the end of the experimental period, acute phase proteins (APPs) haptoglobin and C-reactive protein were examined in individual blood plasma samples. Following each growth study, 16 animals (n = 4) were taken for sampling of ileal chyme and assessing of praecaecal digestibility of protein and amino acids. In addition, digesta samples of the duodenum and the total pancreatic tissue were utilized for determining the enzyme activity of alpha-amylase and trypsin. APP, praecaecal digestibility and enzyme activities did not significantly respond to the PFA supplementaion in diets.