The Effect of a Mixture of Herbal Essential Oils on the Performance of Broiler Chicks Originated From Young and Old Broiler Breeder Flocks

One thousand and eight unsexed one day-old broiler chicks (Ross-308) were randomly divided into 3 treatment groups of 336 birds each, consist of control and two essential oil mixtures (EOM) at level of 24 mg/kg and 48 mg/kg diet. There were not significant effects of dietary treatments on body weight gain of broilers at 21 and 42 days of age. On the other hand, there were significant differences on the feed intake at days of 21 and 42. The addition of 24 mg/kg or 48 mg/kg EOM to the diet reduced significantly feed intake compared to control at day 21of age. The groups added essential oil mixture had significant better feed conversion ratio than control at 21 and 42 days. There were not significant differences on body weight gain between broilers originated from young and old breeder flock at day 21, whereas significant differences were observed on body weight gain at 42 days of age. Broilers from young breeder flock had significant higher body weight gain than broiler from old breeder flock at 42 days of age. No differences were noticed for carcass yield, liver, pancreas, proventriculus, gizzard, small intestine or large intestine weight. Mortality of the broilers was significantly affected by treatments. Supplementation of essential oil mixture in both level to the diet decreased mortality at days 21 and 42. Introduction Antibiotic feed additives have been used for more than 50 years to enhance growth performance and to prevent disease in livestock feeding environments. However, the current trend is to look for alternatives to antibiotic for in feed use because of public concern as to their residues and subsequent occurrence of antibiotic resistance bacteria. As a consequence, new commercial additives of plant origin, considered to be natural products that consumer would accept, have been proposed to animal producer. There is evidence to suggest that herbs, spices, and various plant extracts have appetizing and digestion-stimulating properties and antimicrobial effects (Hernandez et al., 2003; Madrid, et al., 2003 Alçiçek et al., 2004). Breeder age influenced broiler performance and slaughter yield during the various phases of growout period (Peebles et al., 1999). The objective of the present study was, therefore, to examine the effect of dietary supplementation with an essential oil mixture on growth performance of broilers. The second objective was to investigate the effect of broiler breeder age on performance of offspring consuming a mixture of essential oil. Materials and Methods One thousand and eight unsexed one day-old broiler chicks (Ross-308) were randomly divided into 3 treatment groups of 336 birds each consist of control and essential oil mixture (EOM) at 24 and 48 mg/kg diet. Each treatment group was further sub-divided in to 8 replicates of 42 birds per replicate. The EOM contained six different essential oils, derived from selected herbs growing in Turkey, viz. oregano oil (Origanum sp.), laurel leaf oil (Laurus nobilis L.), sage leaf oil (Salvia triloba L.), myrtle leaf oil (Myrtus communis), fennel seeds oil (Foeniculum vulgare), citrus peel oil (Citrus sp.). The diets were isocaloric and isonitrogenous. Experimental diet in mash form and water were provided adlibitum.