Lemongrass extract enhances productive performance, blood biomarkers, immunity, and gut health of broilers

Lemongrass (LG) had various phytochemical components such as saponins, phenols, resins, alkaloids, tannins, flavonoids, glycosides and terpenes, minerals as well as vitamin C which had various pharmacological actions (antioxidant, anti-inflammatory, antibacterial, antibiotic, and antifungal) and growth promoter. The use of LG in broiler nutrition can be optimized the bird performance and gut health. Based on the high nutrition value of LG and absence of sufficient studies on the effect of lemongrass aqueous extract (LGX) on broiler performance and gut health (antioxidant and immune biomarkers and intestinal morphology), the aim of the present study is to investigate the impact of using LGX on productive performance, blood biomarkers, immunity and gut health of broilers.

A total of two hundreds one-day- old male broiler chicks (Cobb 500) were fed on the starter basal diet for 6 days. From day 7 of age onwards, the birds were distributed, at random, into 4 groups. Each group included 5 replicates with 10 chicks per replicate. The birds in group 1 were not administered lemongrass extract (control, LGX0) while chicks in group 2 (LGX100), 3 (LGX200) and 4 (LGX300) were administered the aqueous extract of lemongrass in drinking water at levels of 100, 200 and 300 ml/l, respectively. The experimental period lasted for 35 day. Growth performance parameters, economic efficiency, hematological and biochemical biomarkers, expression of some antioxidant and immune related genes, cecal bacterial counts and intestinal morphological changes all were assessed.

The results indicated that, administration of LGX in drinking water at levels of 200, 100 ml/l, respectively significantly improved (p ≤ 0.001) body weight (BW), body weight gain (BWG) and feed conversion ratio (FCR) than the control but without any effect on economic efficiency index (EEI) and feed intake (FI). On the other hand, the addition of LGX in drinking water at levels of 300 ml/l significantly decreased (p ≤ 0.001) FI, EEI and all growth performance parameters as compared to those other groups. LGX supplemented birds groups exhibited higher Hb, PCV, MCH, platelets, and lymphocytes than the control group. However, the ratio of H/L in LGX100 and LGX200 groups was lower (p ≤ 0.001) than other groups. LGX supplemented groups showed low (p ≤ 0.001) cholesterol, creatinine, MDA and high (p ≤ 0.01) TAC. Up regulation (p ≤ 0.001) of the expressions of catalase, GPX1, and SOD1 were in LGX200 group compared to other groups. While, the proinflammatory genes expression (IL1B, IL6, IFNᵧ, and TNF) were down regulated (p ≤ 0.001) in the LGX200 compared to others. Moreover, LGX200 and LGX300 reduced (p ≤ 0.001) the intestinal pathogens counts (E.coli and Salmonella). Administration of LGX at levels of 200 and 100 ml/l, respectively enhanced (p ≤ 0.001) villi height and crypts depth.

It was concluded that lemongrass aqueous extract can be included at level 100 and 200 ml/l in broilers' drinking water since it resulted in improved weight, feed conversion ratio, blood parameters, immunity and gut health without any deleterious effect on the health and performance of the birds. LGX at a 200 ml/l supplementation level achieved the best results followed by a 100 ml/l level. Also, the tested supplements can be used as natural growth promoter instead of antibiotic and help in solving the global problem of antimicrobial resistant bacterial strains responsible for human and animal diseases.