Comparison of Antibiotic, Probiotic and Great Plantain (Plantago major L.) on Growth Performance, Serum Metabolites, Immune Response and Ileal Microbial Population of Broilers
The objective of the study was to compare the effects of antibiotic virginiamycin, probiotic Protexin® and Plantago major L. (plantain) on performance, serum metabolites, immune response, and the ileal microbial population of broilers. The experiment was carried out with a total of 200 day-old male Ross 308 broiler chickens in a completely randomized design. Chickens were allocated to five groups consisting of T1: control diet (Con), T2: Con+0.02% virginiamycin, T3: Con+0.01% Protexin, T4: Con+0.5% plantain and T5: Con+1% plantain. Each group was divided into four replicates consisting of ten chicks each. In comparison with the control group, body weight gain increased in chickens fed Protexin and 0.5% plantain groups in the starter period, as well as by antibiotic in grower and finisher periods and by 1% plantain in all periods (P < 0.01). Supplementation of plantain and virginiamycin increased (P < 0.01) feed intake in the starter and finisher periods, respectively. Feed conversion ratio improved (P < 0.05) in finisher period only by virginiamycin. All treated birds showed an elevated relative weight of carcass and bursa, and plantain increased relative weight of the spleen (P < 0.01). All treatments demonstrated a hypocholesterolemic effect (P < 0.01) and higher level of plantain (1%) decreased (P < 0.05) serum glucose, triglyceride and low-density lipoprotein-cholesterol as well. The inclusion of Protexin and plantain enhanced immune system with increased white and red blood cells as well as second anti-SRBC immune response and reduced heterophil/lymphocyte ratio in SRBC injected birds (P < 0.05). Virginiamycin decreased ileal microbial population of Lactobacillus while Protexin and plantain increased it (P < 0.01). Meanwhile, 1% plantain suppressed ileal E. coli counts. In conclusion, 1% Plantago major L. performed the best in this study because it led to increased body and carcass weight, lowered serum cholesterol and triglyceride, reduced heterophil/lymphocyte ratio, improved immune response, and ileal microflora.