Effect of powdered rosemary (Rosmarinus officinalis) essential oil and phenolic compounds on broiler chickens zootechnical parameters

This work aims at exploiting the essential oil (EO) and phenolic compounds (PC) of rosemary (Rosmarinus officinalis) in a formulation containing leaf powder stabilized with chitin (1%, w/w) to improve chicken meat and investigate their effect on qualitatively and quantitatively broiler chickens’ growth performances. To such a purpose, chicks, at 1 day of age, were distributed in pens on ground divided into four batches. The two control batches were fed with conventional feed, but the positive control contained flavomycin (0.5 g/kg) as growth factor. The two treated batches received a conventional feed supplemented with two doses of 20 and 50 g/kg of the developed formulation. Essential oil and phenolic compound contents in powdered leaves were, respectively, 1.20 and 22.86% in ethanolic extract. 1,8-Cineole (46.88%), followed by camphor (19.20%), α-pinene (9.56%), L.α.-terpineol (5.91%) and β-pinene (4.40%) were the main compounds of the used EO. The two batches of treated chicks showed a significant improvement in body weight (281.88 and 283.75 g, respectively), a decrease in feed conversion and a reduction in mortality (8%), when compared to the control batches. In addition, the elaborated formulation induced catalase activity used as an indicator of cellular antioxidant activity modulation.