Impetus of phytogenics on broiler performance during periods of infectious stresses

Efficacy of the inclusion of a phytogenic feed additive (PFA) based on a blend of essential oils of Mentha piperita, Pimpinella anisum and Syzygium aromaticum compared to an antibiotic growth promoter (AGP) on broiler performance, faecal shedding and caecal colonisation pattern of certain bacterial species and humoral immune response (HIR) against Newcastle Disease (ND) during infectious stresses in presence of a real pathogen challenge were considered in this study.

A 38 d experiment was conducted with 120 male one-day-old Cobb 400 broiler chicks (3 treatments, 8 replicates). The dietary treatments included feeding a corn-soybean based control diet without added growth promoters and treatment diets containing either bacitracin methylene disalicylate (225 mg/kg) or the PFA (150 mg/kg).

Supplementation of diet with PFA improved body weight gain and feed conversion ratio (p < 0.05) despite oral challenges with pathogenic S. enteritidis and E. coli compared to the control group, the AGP gave intermediate performance.

Faecal Salmonella indicated a lower count (p < 0.05) at 0h after challenge on d 28 in the PFA group compared to Control. At 24h past challenge Salmonella and E. coli numbers were lower in the AGP and PFA groups than Control (p < 0.01).

Enumeration of bacteria in the caecal content at the end of the experiment on day 38 indicated significant reduction of Salmonella, E. coli and Clostridium numbers in the AGP and PFA supplemented groups (p < 0.01) compared to the Control. However, the number of Lactobacillus increased in PFA group in contrast to Control and AGP groups (p < 0.01).

HIR against ND was identical across the diets at 7 d, increased with age (p < 0.01) irrespective of dietary treatments. At 21 d, the ND hemagglutination inhibition (HI) titre was better in the AGP and the PFA groups than Control.

It may therefore be concluded that PFA may be utilized as an effective tool for enhancing broiler performance especially during periods of infectious stresses.