Effect of a vaccination program on physicochemical characteristics, meat texture, and metric traits of the digestive tract and leg bones of broilers

Various immunoprophylaxis programs aimed at protecting chickens from different pathogens and reducing production losses due to mortality or disease are increasingly important in broiler rearing. The aim of this study was to compare the effect of two different commercial prophylactic vaccination programs (H1 vs. H2), using vaccines against Marek’s disease (MD), infectious bursal disease (IBD), infectious bronchitis virus (IBV) and avian metapneumovirus (AMPV) on the chemical composition, physicochemical properties, meat texture, and biometric characteristics of the digestive system and leg bones of Ross 308 broiler chickens. The study material consisted of 20 carcasses (10 male and 10 female) of 42-day-old broiler chickens. After determining the weight of the eviscerated carcass (H1 – 1822.8±212.4; H2 – 2295.6±275.6), the breast and leg muscles were cut out of the dissected elements of the carcass, followed by the measurements of pH₂₄, L*, a*, b* color attributes, electrical conductivity (EC₂₄) and cooking loss. The basic chemical composition and texture characteristics were determined. Measurements of the femur and tibia were taken after separating the meat from the bone. Measurements of the lengths and diameters of the individual intestinal segments were also carried out. The H2 vaccination program had a significant positive effect on the carcass weight of 42-day-old broilers. Chickens subjected to the H1 vaccination program were characterized by significantly lower water and collagen content, pH₂₄, and meat tenderness (higher WB shear force) in the breast, as well as significantly higher protein content in the breast and leg muscles, and a lower percentage of fat in the leg muscles compared to chickens subjected to the H2 vaccination program The dimensions of femur and tibia bones in 42-day-old broiler chickens administered vaccines according to the H2 vaccination program were significantly higher than in chickens on the H1 vaccination program.