The effect of diet supplementation with propolis and bee pollen on the physicochemical properties and strength of tibial bones in broiler chickens

The objective of this study was to determine the effect of diet supplementation with propolis and bee pollen on selected physical, biomechanical and chemical properties of tibial bones in broiler chickens. The experimental materials comprised 384 Ross 308 chickens (four groups, three replications), divided into groups of males and females, and raised to 35 days of age. Control group 1 birds were fed a commercial diet throughout the experiment. Birds of three other experimental groups received for the first two weeks of rearing standard diets with a different content of propolis and/or bee pollen: group 2 - 0.025% propolis, group 3 - 0.5% bee pollen, group 4 - 0.5 % bee pollen and 0.025% propolis. The following parameters of the tibia were determined: weight, length, mid-shaft circumference, vertical and horizontal external diameters, vertical and horizontal internal diameters. The geometric characteristics of the bones were determined based on the above measurements. Mid-shaft shear strength was measured using an Instron universal testing machine 4301 (Instron, Norwood, MA, USA). The crude ash, calcium (Ca) and phosphorus (P) content of the tibia was also determined. Higher values of geometric parameters were noted in the tibial bones of broilers fed a diet supplemented with a combination of propolis and bee pollen, in comparison with birds fed diets containing propolis or bee pollen administered alone. The shear strength values and physical properties of bones were similar in all groups.