Effects of Propolis Extract Supplementation in Breeder and Broiler Diets and It's in Ovo Injection on Immune Status, Blood Parameters, Vaccine-Antibody Response and Intestinal Microflora of Broiler Chick

Abstract

This study evaluated the effects of dietary propolis extract supplementation and in-ovo propolis injection on the immune status, blood parameters, vaccine-antibody response, and intestinal microflora of broiler chickens. A total of 600 Ross 308 broiler chicks were used. Breeder diets were supplemented with 400 ppm propolis extract (P) or left unsupplemented (C) during weeks 38-39. Eggs from the control group (C) were divided into four groups, with in-ovo injections of 400 ppm propolis extract (C-iP) or physiological saline (C-iS) on day 18 of incubation. Untreated eggs formed the control (C-C) or propolis-supplemented (P-C) groups. Chicks were fed either a basal diet (C) or a diet supplemented with 400 ppm propolis extract (P), forming six experimental groups: C-C, C-P, P-C, P-P, C-iP, and C-iS, with 10 replicates per group (10 chicks per replicate). Propolis supplementation significantly increased immunoglobulin levels (IgA, IgG, IgM) compared to the control group. Although it positively affected certain blood parameters, no significant differences were found in post-vaccination antibody titers. The C-C group had the highest total antioxidant levels, while total oxidant levels and oxidative stress index were lowest in the P-P group. Despite positive effects on blood parameters and intestinal microflora, no significant improvements in growth performance were observed. Nevertheless, propolis extract shows potential as an immune enhancer for broiler chickens through parental feeding, standard diets, or in-ovo injection.