Effect of dietary addition of plant extract on growth performance, intestinal microflora and serum biochemistry in broilers

The purpose of the present was to evaluate the effects of dietary different herbal extracts (Gundelia tournefortii L. seed, and Emerald) supplementation on growth performance, serum biochemistry and intestinal bacterial population in broilers. Totally, 280 Ross 308 1-day-old male broiler chicks were distributed into 5 groups of 7 in each consisting 8 replicates per treatment for 42 days. Control group received basal diet, the Emerald at 100 mg/kg diet and G. tournefortii L. seed extract (GTE) at 2, 4 and 8 g/kg diet were added to basal diet. The addition of 4 and 8 g GTE to the diet resulted in significantly higher body weight gain compared with control group (P<0.05). Supplementing the highest level of GTE (8 g/kg diet) significantly increased intestinal lactic acid bacteria counts (P<0.05). However, no differences were observed for feed intake and feed conversion rate at the end of the study (P>0.05). In addition, serum uric acid (UA) and glucose (Glu) concentrations and aspartate amino transferase (AST) and alkaline phosphatase (ALP) were not affected by any treatment (P>0.05). Results of our study showed that different dietary levels of GTE may improve the growth performance by increasing intestinal lactic acid bacteria counts.