Influence of dietary antibiotic (virginiamycin), Inulin and mannanoligosaccharide supplementation on growth performance and carcass characteristics in broiler chickens

Due to growing concerns about antibiotic resistance and a ban for antibiotic growth promoters، this study was conducted in order to determine the effects of two types of prebiotic components as alternatives to antibiotics on growth performance and carcass characteristics of male broiler chickens. A total of 192 male broiler chicks (day-old Hubbard strain) were distributed into a completely randomized design. Experimental treatments (8 treatments with three replicates and 8 birds in each replicate) were: one control diet (without any growth promoter)، one level of antibiotic virginiamycin، and two types of low-digestible carbohydrates ingredients including inulin (1. 5، 3 and 4. 5 % of the diets) and mannan-oligosaccharide (MOS، 0. 1، 0. 2 and 0. 3 % of the diets). For 6 weeks، the birds were fed ad libitum with the mash feed mixtures. Mean body weight and feed intake were recorded weekly. At the end of experiment (on days 43)، two birds were randomly selected from each pen and individually weighed and slaughtered. Then، carcass weight and weight of gastrointestinal parts (including: pancreas، gizzard، liver، proventriculus، heart، intestine and abdominal fat pad) were determined. The SAS General Linear Models (GLM) procedure was used for statistical analysis of data. Based on the results of this experiment، the most feed consumption was related to the inulin-supplemented birds. The highest and the lowest feed consumption were related to the birds fed diets with 4. 5% inulin and 0. 3% MOS، respectively (P<0. 001). Inulin- supplemented birds also had greater body weight gain compared to the control and the birds fed diets supplemented with MOS (P<0. 001). Diets supplementation with inulin led to an improvement in feed conversion which was statistically significant (p<0. 05). There was statistically significant differences between dietary treatments based on abdominal fat pad percentage (p<0. 05). Chicks fed diets supplemented with inulin had significantly lower amounts of abdominal fat pad deposition (p<0. 05). The relative weight of ileum and jejunum (g/cm of segment length) were higher in chicks fed inulin-supplemented diets (p<0. 05).