The effect of using rosemary (Rosmarinus officinalis) in broiler nutrition on production parameters, slaughter characteristics, and gut microbiological population

Abstract

The aim of this study was to investigate the effects of the supplementation of different concentrations of rosemary in broiler diets from day 1 to 42 on growth performance, carcass quality, and cecal microbiological composition of chickens. The research was carried out with 1200 Ross 308 chickens, divided into 4 groups with 6 repetitions per group. The treatment groups were: control group (C) without rosemary, 0.2% rosemary group (0.2R), 0.4% rosemary group (0.4R), and 0.6% rosemary group (0.6R). Production parameters and the European Production Efficiency Factor (EPEF) were determined. At the end of the trial 12 chicks per group were selected and euthanised in order to determine the slaughtering properties and for the microbiological analysis of the cecum contents. The obtained results showed that the use of rosemary in diets leads to increase in average daily gain, feed conversion, and EPEF value. The share of abdominal fat in carcasses was lower (P < 0.05) in the 0.4R and 0.6R groups. Lactobacilli count was found higher in the 0.4R and 0.6R groups (P < 0.001) compared to the C group. These results demonstrate that addition of 0.4% rosemary powder to broiler feed could have positive effects on the gain, feed conversion, fat deposition, and cecal microbiological composition. Further increase in the amount of added rosemary had no additive effect in this research.