Effects of R. coriaria L. and P. farcta extracts as compared to oxytetracycline on broiler performance, serum biochemistry, and immune response

A study was carried out to evaluate the effects of R. coriaria L. and P. farcta extracts as alternatives to antibiotic growth promoters in broilers diet. A total of 300 one-d-old male Ross 308 chicks were randomly allocated to 4 dietary treatments (5 pen replicates; 15 birds per pen) for the 0- to 28-d period، and all data were analyzed in a randomized complete design. Dietary treatments included a basal diet (as control diet، without additive) and 3 similar diets that were supplemented with 200 mg/kg R. coriaria L. extract، P. farcta extract، and oxytetracycline 20%، respectively. The results showed that average daily gain was significantly increased (P<0. 05) by supplementing diets with all feed additives in 7-14 d period and entire (0-28 d). Broilers fed the diets supplemented with each of extracts had a low serum cholesterol levels as compared to control diet (P<0. 05). Moreover، the antibody titer against Newcastle disease virus was significantly increased by supplemented diets (P<0. 05). However، adding feed additive to diets had no significant effect on antibody titer against SRBC، skin thickness due to DNCB challenge and toe-web thickness in response to injection of phytohemagglutinin-P. In addition، supplementing diet with P. farcta caused to a significant increase in relative bursa of fabricius weight in contrast with control diet. Based on current results، it can be concluded that R. coriaria and P. farcta extracts can be used as alternatives to oxytetracycline as a growth promoter in broilers diet.