¹Department of Animal Science, Science and Research Branch, Islamic Azad University, Tehran, IRAN
²Department of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, IRAN
³Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Karaj, IRAN DOI : 10.9775/kvfd.2016.16899 The present study was conducted to evaluate the effects of energy sources and levels on microbial population, jejunal morphology, gene expression of glucose transporter (SGLT1), fatty acid binding protein (FABP) and performance in broilers under heat stress. In a completely randomized design, 600 one-day-old Cobb broiler chickens were assigned to five dietary treatments and four replicates. Chicks were fed diet based on corn as main energy source and energy level based on Cobb standard considered as control (C), corn based diet with 3% lesser energy than control (T1), corn based diet with 6% lesser energy than control (T2), corn and soybean oil based diet according to Cobb standard (T3), corn and soybean oil based diet with 3% upper energy than control (T4). Temperature was increased to 34°C for 8 hours daily from day 21 to 41 to induce heat stress. Chickens in T3 and T4 had higher Lactobacillus population and lower Escherichia coli population than C group (P<0.05). Chickens in T1 and T2 had shorter jejunal villi, deeper crypts, and lower villus height: crypt depth than those fed C, T3 and T4 diets (P<0.05). There were no significant differences among treatments for gene expression of both nutrient transporters (P>0.05). Chickens in T3 and T4 had higher weight gain compared to C, T1 and T2 (P<0.05). Feed intake in T3 was lower than C, consequently, feed conversion ratio of chicks fed T3 was better than C group (P<0.05). In conclusion, replacement a part of dietary energy source with soybean oil might improve intestinal parameters and performance of broilers under heat stress. Keywords : Energy, Lipid, Intestinal morphology, Transporter, Broiler