Two experiments were conducted to determine the chemical composition, metabolizable energy content and effect of grape pomace (GP) with or without tannase enzyme treatment on growth performance of broiler chickens. In experiment 1, the apparent metabolizable energy (AME) and apparent metabolizable energy corrected for nitrogen (AMEn) of GP were determined as 2642.19 and 2641.08 kcal/kg, respectively. Supplementation of tannase enzyme at 0.05 and 0.1 percent of experimental diets significantly (P≤0.01) affected the metabolizable energy content of the diets and the highest improvement was observed with diets containing 0.01 percent tannase enzyme (P≤0.01). True metabolizable energy (TME) and true metabolizable energy corrected for nitrogen (TMEn) were determined based on Sibbald’s procedure. The TME and TMEn of grape pomace were 1844.14 and 1839.83 kcal/kg, respectively. In experiment 2, four dietary treatments (50 birds/treatment) were conducted to study the effect of inclusion of 10% GP with or without tannase enzyme supplementation on growth performance in broiler chicks (0 to 42 days of age). At 10 d of age, the body weight (BW) of the control groups was higher (P<0.05) compared with other experimental groups. Furthermore, broilers fed the control diet had higher (P<0.05) average daily gain (ADG) in the starter (days 0-10) experimental periods. Addition of GP in the chicken diets did not impair growth performance (BW, ADG, average daily feed intake (ADFI) and feed-to-gain ratio (F:G)) of birds fed the grower (days 11-24), finisher (25-42) and the overall (days 0-42) experimental periods compared with other treatments. Among diets supplemented with GP, feed intake and body weight of broilers feeding diet containing 0.1% tannase were higher and the addition of tannase enzyme, improve the metabolizable energy content of GP. تفاصيل المقالة