[ effect of oregano and thyme based essential oils and [beta]-glucanase on performance and nutrients digestibility in broiler chicks fed barley-based diets]

Essential oils [EO] are antimicrobial compounds, but may be beneficial under unfavorable nutritional and environmental conditions. Essential oils produced in Iran are of comparable quality to imported ones. The aim of this study was to compare the effects of Orego-Stim [Essential oil based on Oregano; 0.5 g/kg; imported] and Anti-Biophin [Essential oil based on Thyme; 1 g/kg; local] essential oils on performance and precaecal digestibility of nutrients in broiler chicks fed barley-corn based diets with and without b-glucanase [0.05 g/kg]. At the beginning of the second week of rearing period, 192 chicks of mixed sex were allotted into six groups of four replicates with eight chicks per replicate according to a 2x3 factorial experiment arranged as a completely randomized design. Inclusion of Orego-Stim or Anti-Biophin in barley based diets caused a significant [p<0.05] improvement in total feed conversion, final body weight and nutrients digestibility, without a significant effect of [beta]-glucanase addition to the diets. The type of essential oils [imported vs. local] did not affect the measured characteristics. Feeding broiler chicks with barley based diets, supplemented with essential oils, decreased the anti-nutritional effects of barley grains in these diets and improved broiler performance, without the need to supplement the barley-based diets with b-glucanase. Because of the lack of any significant difference between the imported and locally-produced essential oils, and the higher cost and scarcity of the imported EO, domestic products such as Anti-Biophin at recommended levels can replace the imported ones