Objective: This study was conducted to evaluate the effects of different dietary levels of bee pollen (BP) on growth performance, immune responses, and serum biochemical parameters of broiler chickens. Considering the increasing interest in natural feed additives as alternatives to antibiotic growth promoters, BP was investigated as a functional ingredient with potential nutritional and physiological benefits.

Methods: A total of 192 broiler chicks were assigned to a completely randomized design with four dietary treatments and four replicates per treatment (12 birds per replicate) for 24 days. The experimental treatments included: 1) control diet (without bee pollen), 2) diet supplemented with three g/kg BP, 3) diet supplemented with six g/kg BP, and 4) diet supplemented with nine g/kg BP. Growth performance was evaluated during the starter (1–10 d), grower (11–24 d), and overall (0–24 d) periods. Immune responses and serum biochemical parameters were assessed at the end of the experiment.

Results: During the starter period, no differences were observed in daily weight gain (BWG), daily feed intake (DFI), and feed efficiency among treatments. During the grower period and the entire experimental period, the BWG of chickens receiving diets containing six and nine g/kg of BP was higher than that of the control group (P < 0.05). However, no differences were observed among treatments in DFI and feed efficiency during these periods. Antibody titers against and Newcastle disease virus and avian influenza virus, as well as the relative weights of the spleen and bursa of Fabricius, were not affected by the treatments. The relative weight of the thymus in chickens receiving six and nine g/kg of BP was higher than that of other chickens (P < 0.05). Serum triglyceride and very low-density lipoprotein levels in birds receiving diets containing nine g/kg of BP were lower than those in control chickens and those receiving three g/kg of bee pollen (P < 0.05). Serum alanine aminotransferase levels in birds receiving three and nine g/kg of BP were lower than those in control chickens (P < 0.05). Furthermore, total antioxidant capacity in the serum of birds receiving BP was higher than that of control chickens (P < 0.05). Creatinine levels (P = 0.057) and lactate dehydrogenase enzyme activity (P = 0.065) tended to decrease in chickens receiving BP.

Conclusion: Based on the results of this study, the addition of BP to the diet of broiler chickens, particularly at the level of nine g/kg, improved growth performance, relative thymus weight, lipid metabolism indices, liver enzyme activity, and serum antioxidant capacity. Therefore, the use of this level of BP as a natural and functional additive in the diet of broiler chickens is recommended.