Effect of feeding different levels of wheat gluten meal and lysine amino acid on growth performance and ileal protein digestibility in broiler chickens

Wheat gluten is one of the byproducts of starch plants that can be used in broiler nutrition as a protein source. This experiment was conducted to evaluate the effects of different levels of wheat gluten meal and lysine amino acid on performance, carcass yield and ileal protein digestibility in broiler chickens. Two levels of dietary lysine (100 and 85% of the levels recommended by Ross 308 management guide) and 4 graded levels of wheat gluten meal during 0-21 (0, 4, 8 and 12%) and 21-42 days of age (0, 7, 11 and 15%) were used in a 2×4 factorial arrangement of treatments based on a completely randomized design. Accordingly, 600 day-old broiler chickens were divided into 40 groups of 15 chicks per each group, with each 5 groups being assigned to one of the 8 treatments. The results showed that dietary lysine levels had no significant effects on growth performance and ileal protein digestibility, but dressing percentage in chickens fed diets containing 100% lysine was significantly higher than those fed diet with 85% level (p<0.05). Feeding diets containing 12% wheat gluten significantly (p<0.05) improved average body weight gain and feed conversion ratio during starter period. Dietary level of wheat gluten had significant effect on average abdominal fat percentage (p<0.05). Furthermore, ileal protein digestibility significantly (p<0.05) increased as inclusion rate of wheat gluten increased from 0 to 15% in grower diets. The results indicate that with inclusion of 12 and 15% wheat gluten in starter and grower diets, respectively, an appropriate performance can be expected for broiler chickens, but decreasing lysine levels of these diets cause decrease in carcass yield of the chickens.