Abstract
The study evaluated the effect of ViandiPlus (Idena®) on the performance and carcass characteristics of uncastrated Nellore males in a feedlot system in Brazil. ViandiPlus is a blend of essential oils (containing linalool and geranyl acetate) and yeast cell wall components. Two trials were conducted at Instituto Zootecnia (IZ) in 2022, and University Federal of Goias (UFG) in 2023. At IZ, animals were kept in two collective pens (40 animals each) equipped with Intergado® automatic feeders, allowing individual intake measurement of water and feed. In UFG, animals were divided into 14 collective pens (7 pens/treatment, 6 animals/pen, 84 animals in total) with collective troughs (feed and water). Animals were randomly allocated to pen in both trials. The treatments used were: CON - Negative control, without additive and VIANDI (containingViandiPlus at 1.7 g/kg of DM). Diets consisted of 30% of maize silage and 70% of concentrate at IZ, and 10% of sugarcane bagasse and 90% of concentrate at UFG, based on DM. Adaptation phases lasted 14 days at IZ and 18 days at UFG, with feedlot fattening periods of 116 and 94 days, respectively. Animals were weighed after 16 hours of fasting at the start of the adaptation phase and the end of the fattening phase, just before slaughterat the beginning and end of the trials. Carcass gain was calculated assuming a carcass dressing of 50% of body weight at the start of the trial and considering carcass gain post-slaughter. Ultrasonography was used to calculate rib eye area (cm²) and subcutaneous fat thickness (mm) in the loin and rump, according to Herring et al. (1994). At IZ, 13 animals had to be removed during the trial as they did not adapt to the Integrado system, and 1 animal were removed at UFG as did not adapt to the diet. In total 67 and 83 animals were used for statistical analysis, respectively. Individual data were analyzed using a linear mixed model fit by the REML procedure in RStudio, accounting for treatment, trial, and their interaction, with initial body weight as a covariate. Significance was determined at P≤0.05, with trends noted at 0.05>P≤0.10. VIANDI improved final body weight (547 kg vs. 537 kg, P=0.047) and average daily gain (1.54 kg/day vs. 1.46 kg/day, P=0.045) and carcass weight (303 kg vs. 298 kg, P=0.062) compared to the control. The rib eye area was larger (81.7 cm² vs. 79.0 cm², P=0.047) in the VIANDI group, without affecting subcutaneous fat thickness (loin and rump). ViandiPlus positively influenced performance and rib eye area in feedlot diets.