Oregano Essential Oil as Antimicrobial Agent in Broilers Diet

The study was carried out to evaluate the dietary supplementation of oregano essential oil on performance and antimicrobial activity of broilers. A total of 250 day-old male were distributed in a completely randomized design divided into five groups with five replicates, each given a basal diet with avilamycin plus salinomycin (positive control) or a basal diet without added avilamycin and salinomycin (negative control) or basal diet with only added avilamycin or a basal diet supplemented with 0.5g of oregano oil/kg diet, or 1.0g of oregano oil/kg diet. It was observed lower frequency of gram-positive bacteria in the ileum of the negative control group compared to chickens treated with the positive control group or supplemented with oregano oil (p < 0.01). Lactobacillus spp. had a higher growth in the positive control group or supplemented with 1g of oregano oil/kg diet (p < 0.05). However, the frequency of Lactobacillus spp. in broilers supplemented with 0.5g of oregano oil/kg diet was lower than those supplemented with 1g of oregano oil/kg diet (p < 0.05) as well, as it did not differ from the negative control group (p > 0.05). It was observed that the use of 1.0g of oregano oil/kg diet resulted in the lower relative intestine weight (p < 0.05) which did not differ significantly from the positive control group (p > 0.05). The results showed that the dietary oregano oil exerted growth-promoting effect on broilers at 1.0g of oregano oil/kg diet by the increase in the Lactobacillus spp. frequency and the decrease in intestinal weight in