Effect of Supplementation of Hen Diet with Pennyroyal Extract (Mentha pulegium) on Performance, Egg Quality and Yolk TBARS Values

The aim of this study was to investigate the effects of pennyroyal extract supplementation at different levels (0, 32.5, 65 and 130 mg/kg) and 50 mg/kg BHA (Butylated hidroxyanisole) into diets of laying hens on performance, egg quality traits, thiobarbituric acid reactive substans (TBARS) of yolk, the contents of malondialdehyde (MDA), superoxide dismütase (SOD) and glutation peroxidas (GSHPx) in serum.Sixty Lohman LSL white layers, 40 weeks of age, kept in individual cages were assigned randomly to five treatment groups, each group included 12 hens.The hens received one of five diets with 0, 32.5, 65 or 130 mg/kg pennyroyal extract and 50 mg/kg BHA, respectively.Experiment lasted for 60 days.At the end of the experiment, the supplementation of pennyroyal extract did not affect feed intake, rates of albumen, yolk and shell of egg, shell tickness, spesific gravity, Haugh unit and some serum parameters.It however, significantly improved feed conversion rate and egg production.Also, egg weights of groups fed on diets including 65 and 130 mg/kg of pennyroyal extract increased in present study.It was found that supplementation of 130 mg/kg pennyroyal extract significantly improved shell strength.TBARS was reduced in eggs stored during 42 days (P<0.05).In conclusion, pennyroyal extract ameliorated performance and lipid oxidation of eggs.