effects of particle size and dietary inclusion rate of barley hulls on the performance, nutrients digestibility and production cost of broiler

this experiment was carried out using 200 ross 308 broiler chickens in a completely randomized design with 5 treatments and 4 replicates. the true metabolisable energy of the barley hulls were determined using cecectomized roosters.the dry matter, true metabolisable energy, ash, ether extracts, crude protein, crude fiber, ndf, adf, ca and total p content of barely hulls were: 92%, 978 kcal/kg, 3.53%, 4.26%, 12.26%, 12.6%, 52.1%, 23.5%, 0.9% and 0.6%, respectively. the experimental diets were consisted of a control hulls free diet and four diets containing 0.75 or 1.5 percent barley hulls with particle sizes of less than 1 mm or between 1-2 mm. the barley hulls improved weight gain and feed conversion ratio and particularly the diet contained 1.5 percent barley hulls with particle size of 1-2 mm was more effective in this respect (p < 0.05). the same trend was observed in gizzard weight (p < 0.05). dietary barley hulls improved dry matter, crude protein and ash digestibility (p < 0.05). all the barley hulls contained diets reduced feed cost per kg weight gain of broiler chickens, which could be a surprising finding. the results of the present study suggest that including barley hulls with 1-2 mm particle size at 1.5 percent of the diet could positively affect performance traits and feed cost of broiler chickens.