Effects of a functional mix feed additive on growth performance, meat quality and vaccine immunity in broiler chickens

In recent years, efforts to reduce antibiotic use in the poultry sector have generated increased interest in alternative feeding strategies. Natural ingredients such as propolis, omega-3 fatty acids, and Lactobacillus subtilis are increasingly being utilized as feed additives to increase production performance and bolster immunity in poultry. This study systematically investigated the effects of a feed additive comprising propolis, omega-3 fatty acids, and Lactobacillus subtilis on growth performance, meat quality, and Newcastle vaccine immunity in broiler chickens. The research involved 144 mixed-sex Ross 308 broiler chicks, aged one day, which were divided into four distinct groups: a control group (T1), a group receiving only the vaccine (T2), a group receiving both the vaccine and the feed additive (T3), and a group receiving only the feed additive (T4). The chicks were monitored over a period of 42 days to evaluate the outcomes. The results indicated that chicks in group T4 achieved the greatest live weight gain, with an average of 2275 g, and exhibited a superior feed conversion rate of 1.85. Additionally, color changes were assessed separately for the skin-on and skin-off treatments among the study groups. The L color change values were significantly greater in the T1 and T2 groups than in the T3 and T4 groups (p = 0.003). Prior to vaccination, all groups displayed negative antibody levels, with no significant differences observed in the sample/positive (S/P) ratios among them. However, postvaccination evaluations revealed statistically significant differences in S/P ratios across the groups (p < 0.001), with the T1, T2, and T4 groups showing notably lower values. The vaccinated groups presented an increase in the immune response, which contributed to a more resilient profile against infectious diseases. These findings highlight the positive effects of the mixed feed additive on the efficacy of vaccination, suggesting that its inclusion not only enhances overall performance in broiler chickens but also strengthens their immune response to the Newcastle vaccine, thereby promoting a healthier and more resilient poultry production system.