Influence of Silymarin-Phyllanthin blend supplementation on growth performance, carcass traits, serum biochemistry, and immune response in broiler chickens

Liver health is pivotal for optimal growth, metabolic efficiency, and disease resistance in broiler chickens, yet it is often compromised under intensive rearing conditions. Addressing this challenge through nutrition, this study investigated the effects of graded dietary supplementation with a Silymarin-Phyllanthin blend (SPB) on growth performance, carcass attributes, nutrient digestibility, serum biochemical and antioxidant enzyme profiles, immune responses, and targeted gene expression regulation in broilers. The objective was to determine whether targeted SPB supplementation can enhance poultry production while supporting liver function and overall health. A total of 4,500 male Cobb 430 broiler chicks were used across three independent trials (1,500 birds per trial). In each trial, birds were randomly allocated to a control group and three dietary treatment groups supplemented with varying levels of herbal nutrient blend (SPB), with all treatments administered throughout the Pre-starter, starter, and finisher phases. In Trial 1, the dietary treatments consisted of a control diet (CD) and CD supplemented with SPB at 150, 200, or 250 g/tonne. In Trial 2, the experimental groups received the control diet and CD supplemented with SPB at 200, 250, or 300 g/tonne. In Trial 3, the treatments included the control diet and CD supplemented with SPB at 250, 300, or 400 g/tonne. SPB supplementation showed a clear trend (P<0.05) toward increased body weight gain (BWG) and reduced feed conversion ratio, indicating enhanced feed efficiency. While carcass yield and breast muscle percentage were unaffected (P>0.05), abdominal fat deposition was notably (P<0.05) reduced at lower SPB doses, reflecting healthier carcass profiles. Apparent ileal digestibility of both energy and nitrogen increased in a dose-dependent manner, with optimal benefits observed at 300g/ton. Serum biochemistry showed stable or improved liver enzymes (SGPT, SGOT, GGT, ALP), indicating the hepatoprotective potential of SPB. Antioxidant capacity, as evidenced by higher glutathione reductase activity, suggests improved oxidative defence mechanisms. Immunological assays further revealed a dose-dependent improvement in antibody titers against Newcastle disease and trends toward greater cell-mediated immunity. Targeted gene expression regulation of IGF-1 and FABP1 showed a positive association with broiler growth performance, while PPARγ and APO-A1 showed a negative association, upon supplementation with graded doses of SPB. In conclusion, dietary inclusion of the multi-nutrient blend at 300g/ton optimizes growth performance, feed utilization, hepatic health, and immune competence in broilers, without compromising carcass quality. These findings highlight SPB as a promising functional feed additive for sustainable and profitable poultry production.