Effect of Licorice Extract and Prebiotic on Laying Hen Performance and Egg Quality in the Pre and Early Laying Periods

This study was conducted to investigate the effect of licorice (Glycyrrhizaglabra) extract, Active-mos (R) prebiotic, and flavomycin antibiotic on performance, egg quality, and body mass status in the pre and early laying periods. A total of 180 Leghorn pullets (Hy-line W-36), were assigned into 6 treatments (5 cages/treatment, 6 pullets/cage) in a completely randomized design. The experimental treatments included control (feed additive -free-diet), and control supplemented by licorice extract (5 and 10 g/kg of diet; as LIEX5 and LIEX10, respectively), flavomycin antibiotic (400 and 650 mg/kg of diet; as FL400 and FL650, respectively), and Active-mos (R) prebiotic (1 kg/ton of diet; as ACPR). Birds were raised in a cage-layer facility. Body weight, feed intake, and feed conversion ratio were determined weekly. Body mass index was recorded before and after using the treatments. Also, the growth, egg quality, egg cholesterol, serum cholesterol, and triglyceride were tested. During weeks 18 to 19 of age, birds received control, FL650, and ACPR treatments showed greater feed intake compared to LIEX10. The body weight of birds that received FL400 diet was greater than LIEX5 and ACPR treatments at weeks 17 to 19 of age. All treatments, except for ACPR, decreased serum cholesterol compared with the control treatment (P < 0.05). No significant effect on feed conversion ratio, egg production, and body mass index was observed by treatments throughout the study (17-25 wk). Furthermore, there was no significant effect of treatments on the eggs' internal and external quality status, egg cholesterol, and serum triglyceride by treatments. However, more research is needed on the use of licorice extract and prebiotics as antibiotic alternatives and their effects on the body mass index in laying hens during pre-and early-laying periods.