Effect of dietary inclusion of Mentha piperita on histomorphometric parameters of bursa of Fabricius, cecal tonsils and thymus of Broiler chickens

To evaluate immunostimulatory effects of Mentha piperita on histological characteristics of bursa of Fabricius, cecal tonsils and thymus of broilers 40 male one-day old Ross 308 chickens were randomly allocated into 5 groups of 8 birds in separate cages. Four groups received dried M. piperita powder at 10, 20, 40 and 80 g/kg of diet while group 5 birds were kept as control and fed with standard diet. After 6 weeks all birds were slaughtered and samples of bursa, cecal tonsils and thymus were removed. Six-micrometer thick slides were made and stained with H&E for evaluation of histomorphometrical parameters by a linear graticule under light microscope. Data analysis was performed by ANOVA method. Consumption of diet supplemented with M. piperita resulted in a dose-dependent significantly increase in number of follicles and height of plicae in bursa. Villi became shorter and wider in cecal tonsils while the density of follicular units significantly increased. Lobular thickness increased in thymus. The results of this study demonstrate that dietary consumption of M. piperita during rearing period is associated with expansion and stimulation of histological immune structures of bursa, cecal tonsils and thymus in broiler chickens.