Özet:

This study was conducted to investigate the influence of dietary propolis and caffeic acid supplementation on performance, egg quality and serum variables of laying hens. One hundred and ninety two, 40 weeks old, White Leghorn hens were assigned to 6 groups with 4 replicates. Hens were fed basal diet (control group) or 0.5, 1, 3, 6 g/kg propolis and 0.5 mg/kg caffeic acid supplemented basal diets (treatment groups) for 12 weeks. Propolis and caffeic acid addition did not affect live weight, feed consumption, egg yield and feed efficiency (P>0.05). However, egg weight increased significantly in the 0.5 g/kg caffeic acid suplemented group (P<0.01). The highest egg albumen index and Haugh unit were determined in the 6 g/kg propolis supplemented group (P<0.001). There were no significant differences among control and treatment groups for serum aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities. Addition of propolis at different doses and caffeic acid to diet reduced serum alanine aminotransferase (ALT) (P <0.01), triglyceride (TG) and total cholesterol (TC) levels (P<0.05) and increased serum high density lipoprotein (HDL) (P<0.001). Serum glucose levels were significantly low in the 6 g/kg propolis and caffeic acid groups of than that of the control group, but higher in the 0.5 and 3 g/kg propolis groups (P<0.001). On the other hand, total protein (P<0.01) and albumin (P<0.001) were low in propolis and caffeic acid groups except 3 g/kg propolis group than control group. Propolis (excluding 1 g/kg level) and caffeic acid increased serum calcium (Ca) and magnesium (Mg) levels (P<0.001). However, serum inorganic phosphorus (Pi) levels were not affected by treatments. In addition, serum malondialdehyde (MDA) levels decreased in groups supplemented with 3 and 6 g/kg propolis and 0.5 mg/kg caffeic acid (P <0.01). As a result, the addition of propolis to the diet of laying hens effected positively egg quality and some serum parameters without adversely affecting performance

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