PSVI-25 A Phytogenic Additive Improves Immune Responses of Growing Beef Cattle on Grazing System

Abstract

Abstract Our objective was to evaluate the effect of a phytogenic additive in protein supplement for grazing Nellore young bulls on serum protein profile. One hundred and fourteen animals (iBW, n = 114; 273 ± 4.46 kg) were allocated for 152 days in six pastures of Brachiaria brizantha cv. Marandu (̴7 ha each), and randomly distributed in six treatments with or without additives on protein supplement (30% crude protein). Treatments were: 1) Negative Control (CON), with no additive; 2) Positive Control, with 15 ppm of Monensin (MON); 3) Digestarom (DSM Nutritional Products) at 0.2 g· animal-1· /day-1 (D0.2); 4) Digestarom at 0.4 g· animal-1· /day-1 (D0.4); 5) Digestarom at 0.6 g· animal-1· /day-1 (D0.6) and 6) Digestarom at 0.8 g· animal-1· /day-1 (D0.8). Supplement was offered ad libitum. Additives dosages were adjusted weekly to achieve the targeted dose/animal. Blood samples were collected in the last day and analyzed for positive acute phase proteins (increases with the inflammation response), haptoglobin (HAP) and glycoprotein (GLY); negative acute phase protein (decreases with the inflammation), transferrin (TRA); and Immunoglobulins A and G. Data were analyzed using SAS PROC GLIMMIX. Significance of 5% was adopted. Contrasts of use of Monensin, use of Digestarom, type of additive, and linear and quadratic effects of Digestarom were evaluated. Compared with MON, Digestarom decreased (P < 0.05) HAP (124 vs. 76.2 mg/dL) and GLY (1,361 vs. 85.6 mg/dL). TRA increased (P < 0.05) with Digestarom (310 and 307 mg/dL for D0.6 and D0.8, vs. 204 and 177 mg/dL for CON and MON). Digestarom increased (P < 0.05) immunoglobulins A (193, 218 and 225 mg/dL for D0.4, D0.6 and D0.8) and G (1.5 g/dL for D0.4, D0.6 and D0.8) compared with CON (IgA 146 mg/dL and IgG 0.9 g/dL) and MON (IgA 93 mg/dL and IgG 0.3 g/dL). Digestarom levels also showed a quadratic effect on TRA (including 165 and 245 mg/dL for D0.2 and D0.4) and on IgA and IgG (including 124 mg/dL and 0.8 g/dL for D0.2). Overall serum protein responses of the animals receiving Digestarom (reduced haptoglobin and glycoprotein, and graeter transferrin, IgA and IgG) demonstrates that these animals had improved immune responses and could be better able to respond to infectious and stress challenges.