Effect of peppermint (Mentha Piperita L.) in broiler chicken diet on production parameters, slaughter characteristics and gut microbial composition
This study was conducted to evaluate the productive performance, carcass quality and cecal microbial composition of broiler chickens fed diets supplemented with different concentrations of peppermint powder. Peppermint (Mentha piperita L.) belongs to the family Lamiaceae, and is characterized by strongly scented leaves. It is used as a remedy in herbal medicine, and consists of up to 4% essential oil (with 35–45% menthol). The study included 960 one-day Ross 308 broilers of both sexes. The chickens were assigned to 4 treatments and were housed in 24 boxes, with 6 replicates per treatment. Broilers received three diets (starter, grower and finisher) differing in the amount of supplemental peppermint powder, and were fed ad libitum. The diets contained different levels of supplemental peppermint powder: control group (C) – without peppermint, group I – 0.2% peppermint, group II – 0.4% peppermint, and group III – 0.6% peppermint.
The body weight of chickens was measured when changing their feed (days 10 and 24) and at the end of the experiment (day 42). Average feed intake, average daily gain, mortality, feed conversion, and the European Production Efficiency Factor (EPEF) were determined. At the end of the trial, 12 broilers of both sexes were randomly selected from each group and slaughtered to measure their carcass traits. Positive effects of peppermint supplementation were identified. Group III chickens had significantly higher (p<0.01) values of average daily gain, feed conversion and EPEF compared with C broilers. There were no significant differences in slaughter results (dressing percentages, the proportions of breast, drumsticks, thighs, wings, abdominal fat, heart, liver and stomach). The total numbers of aerobic bacteria and Lactobacilli did not differ significantly between groups. Escherichia coli count was lower in Group II and III birds (p<0.05) compared with C ones. The results showed that the supplementation of 0.6% peppermint powder to broiler feed had positive effects on weight gain, feed conversion and cecal microbial composition.