Effects of dietary Glycyrrhiza polysaccharide on growth, serum biochemistry, immunity, and egg laying in quail

This study was conducted to evaluate the effects of dietary supplementation with Glycyrrhiza polysaccharide (GCP) on growth performance, serum biochemistry, immunity, and egg laying in female quail. 300 1-day-old female quail were sorted into four dietary treatments with five replicate cages of 15 birds each. The basic diet in the four treatment groups was supplemented with 0, 500, 1000 and 1500 mg/kg GCP, and the experiment continued for 80 days. Results showed that dietary supplementation with GCP significantly (p < 0.05) increased average daily gain in a dose-dependent fashion, and decreased (p < 0.05) the feed-to-gain ratio and mortality. The relative weights of the thymus and bursa of Fabricius increased (p < 0.05) linearly with increasing dose of GCP from 0 to 1500 mg/kg on day 20. GCP birds showed higher serum levels of protein, glucose, immunoglobulin A and immunoglobulin M, but lower serum triglycerides (p < 0.05) on day 50. GCP increased (p < 0.05) average laying rate and average egg weight linearly from days 60 to 80, whereas feed to egg ratio was decreased (p < 0.05). Taken together, these results revealed that GCP could improve growth performance, serum biochemistry, immunity, and egg laying in female quail. Therefore, GCP may be a potential replacement for antibiotic growth promoters in poultry.