Effects of dietary Turkish propolis as alternative to antibiotic on growth and laying performances, nutrient digestibility and egg quality in laying hens under heat stress

In order to evaluate the efficiency of a dietary supplementation with propolis (a product of honey bees) in poultry, the growth and laying performances, the nutrient digestibility and the egg qualities were investigated in Hyline White Leghorn, 42 week old, laying hens reared under a chronic heat stress (ambient temperature of 34 degrees C for 9 hours per day for 2 months) supplemented with propolis (3g/kg) or with antibiotic (flavomycin 50 mg/kg) or not supplemented and compared with laying hens reared under thermoneutral conditions (constant temperature of 22 degrees C), each group containing 30 birds. In addition to the significantly mortality increase, body weights and weight gains, food intake and efficiency and egg production as well as the nutrient digestibility (dry and organic matters, crude proteins and ashes) and the egg shell qualities (thickness and weight) were dramatically altered by the heat stress exposure compared to thermoneutral conditions (P < 0.05). However the dietary supplementations of hens with flavomycin or with propolis have significantly reduced the negative effects of heat stress on performances, nutrient digestibility (dry matter, crude proteins and organic matter) and egg shell characteristics (P < 0.05). No significant difference on any parameter was evidenced between the 2 supplemented groups. These results demonstrate that propolis exhibited the same efficiency than antibiotic for restoring performances, nutrient digestibility and egg qualities in laying hens chronically exposed to heat stress.