PSII-3 Carbohydrases enzymes improve the productive performance of grazing Nellore steers fed different nutritional plans during dry season
Abstract The aim was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on productive performance of grazing Nellore bulls in dry season. A total of 102 Nellore bulls (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 bulls/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors different nutritional plans (2): mineral-proteic supplementation (PS; Fosbovi® Proteico 35) offered at 0,1% BW or mineral-protein-energetic supplementation (PES; Fosbovi® Proteico-Energético 25) offered at 0.3% BW; and levels of enzymatic carbohydrases blend (3):0,00 (control), 4,75 or 9,50 g/animal/day. The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX) and included in the supplements (both enzymes and supplements provided by DSM Nutritional Products Brasil S.A.). Supplement intake and animal weighting were carried out daily and individually by an automatic scale system installed in each paddock, thus, animal was considered the experimental unit. Data were analyzed using PROC MIXED of SAS and means were compared by polynomial regression. A quadratic effect was observed on enzyme level for ADG in both nutritional plans (P = 0.014), with intermediary dosages presenting the highest values of ADG for PS (0,283 vs. 0,188 kg/day) and PES (0.429 vs. 0.391 kg/day), over control respectively. Although no linear and quadratic enzyme effect was observed for final BW (FBW), animals supplemented with PES presented 20,06 kg higher FBW compared to PS (341,63 vs. 321,57 kg, P < 0.001). An increasing linear effect was observed for supplement intake (kg/day), for both PS and PES (P = 0.020). According the polynomial regression, it is recommended to include 4.67 g/day of carbohydrases blend in PS and 3.77 g/day in PES, being the carbohydrases blend a viable technology to grazing cattle. Moreover, mineral-protein-energetic supplementation can optimize Nellore bulls performance during dry season.