Evaluation of a phytogenic feed additive on performance, nutrient digestion, and absorption in turkey poults

The objective of this experiment was to determine the effects of a phytogenic feed additive on turkey poult performance over a 6-week brooding period. A total of 864 male Hybrid Converter turkey poults were placed into pens that were randomly assigned one of three experimental groups. The three experimental diets included a corn-soy diet with no additives (PC), a similar diet with a 1.5 % reduction in crude protein and key amino acids (NC), and the same NC diet with Digestarom® (PFA) included at a rate of 1 g/kg. Performance-based experimental units (EU) consisted of one pen of 24 poults, with 12 EU per treatment. Mortality were recorded daily, and feed intake (FI), mortality corrected feed efficiency (FE), and body weight gain (BWG) were determined on days 14, 28, and 42. Samples were taken on days 28 and 42 to determine the coefficient of apparent crude protein digestibility (CPD). The expression of genes was determined for selected enzymes and nutrient transporters. The PFA improved poult BWG beyond that of the PC and NC on day 14 (263.7 vs. 252.5 and 252.7 g/bird, respectively; P ≤ 0.05), and there were no differences in FE (P > 0.05). On day 28, BWG was similar among treatments, although the PC had the highest FE (P < 0.01). The birds fed the PFA and PC diets had greater BWG on day 42 compared to the NC (2,447, 2,460, and 2,364 g/bird, respectively; P ≤ 0.01), and the PC had the highest FE (P ≤ 0.01). No differences were observed in the mRNA expression of EAAT3, PepT1, SGLT1, GLUT5, trypsin, amylase, or lipase. On day 42, the birds fed the PFA had lower ileal aminopeptidase activity (8.08 U/g total protein) compared to the NC (10.25 U/g total protein), while the PC was intermediate (8.58 U/g total protein), suggesting the PFA may be improving protein utilization (P = 0.05). Therefore, by the end of the experiment the PFA improved poult BWG to that of the PC; however, it had minimal effect on FE and nutrient digestion parameters.