CONICET | Buscador de Institutos y Recursos Humanos

Phytogenic compounds, probiotics and organic acids are used in broilerfeeds as an option to AGPs due to their ability to emulate properties ofantibiotics. This study?s goal was to compare a field AGP (virginiamycin100 g/MT) program (T1) with two antibiotic free programs: Lactococcus based probiotic+yeast MOS+a blend of Italian Chestnut-C/ArgentineQuebracho-Q bioactive extracts (T2), or, a blend of C+Q alone (T3). A42-day floor pen trial was conducted with a total of 1,575 of Arbor Acres®Max male broilers which were randomly distributed to 3 treatments (45total pens); each treatment (525 birds) was fed to 15 pens of 35 birds/pen.Body weight, feed consumption and conversion were determined at 21and 42 days of age. Livability and overall health were routinely measuredand recorded. Intestinal health (lesion score) was evaluated at day 21 and42. Caecal and litter samples were taken at these times for microbiota,bacterial, and moisture determination, and, measurement of the spreadof environmental antimicrobial resistance. Body weight (T1; 1.052; T2:1.072; T3: 1.077, kg, respectively) and feed conversion were significantlyimproved (P < 0.05) on day 21. No significant differences among treatments on day 42 were observed for body weight-kg (T1: 2.978; T2: 2.975;T3: 3.003) and feed conversion-Feed/Weight (T1: 1.728; T2: 1.714; T3:1.715). Microbiota analysis showed a differential effect among treatments,i.e., alpha diversity, number of species and specific groups of beneficialbacteria were improved by the non-AGP treatments. Food pad and intestinal health was generally good and similar among treatments. Both non-AGP treatments showed a tendency to reduce antibiotic resistance inrepresentative bacteria from the intestine and litter