Prof. Dr. Mohammad Toghyani

Two experiments were conducted to investigate the effect of fibrous materials with one single diet or by choice feeding on performance, intestinal morphology, immunity, and fiber preference in broiler chicks. In experiment 1, 240-day-old chicks (Ross 308) were assigned to one of 4 treatments, comprising 5 replicates per treatment in a completely randomized design. Dietary treatments included: a basal diet (control) or 30 g/kg sugar beet pulp (SBP), 30 g/kg rice hull (RH), or 30 g/kg equal combination of them (SBP/RH) added to the basal diet. Results showed SBP and SBP/RH impaired daily weight gain (DWG) in the growing period compared with control (P < 0.05). Additionally, chickens that received SBP had deteriorated FCR across the entire rearing period (P < 0.05). In comparison to control and SBP, supplementing SBP/RH significantly increased antibody titer against Newcastle disease virus (NDV; P < 0.05) at 23 d of age. Furthermore, SBP reduced duodenal and ileal villus height compared with control at 21 d of age. In experiment 2, a total of 240 chicks were allotted to 4 experimental treatments of feeding: 1) control; or choice feeding between 2) control and SBP (C-SBP); 3) control and RH (C-RH); 4) control and SBP/RH (C- SBP/RH). Results indicated that chicks had a tendency to use separate sources of fiber. RH was consumed lower than C-SBP/RH and C-SBP in starter and growing periods, respectively (P < 0.05). Chickens choice fed RH and SBP/RH had greater daily feed intake than control across 14 to 28 d of age (P < 0.05). However, DWG reduced in all fiber fed birds (P < 0.05) and resulted in impaired FCR in broilers of the C-SBP group (P < 0.05). In addition, choice feeding of SBP/RH increased antibody titer against NDV as compared with control and SBP (P < 0.05). In conclusion, fiber inclusion in both experiments impaired growth performance but an equal combination of fiber improved immunity. In addition, broilers had a tendency to use separate sources of fiber.