Selected Herbal Plants as Growth and Health Promoters in Broiler Chickens

A series of experiments were conducted to examine the effect of herbal supplementation as a growth and health promoters. An in vitro procedure was used to determine the antibacterial activity of the fruit of Solanum torvum, whole plant of Euphorbia hirta, and rhizomes of Zingiber officinale, Curcuma longa and Zingiber zerumbet. Among the five herbal plants studied only the aqueous extract of Euphorbia hirta showed considerable growth-inhibiting activity against Staphylococcus aureus. Phytochemical screening and a toxicity evaluation of the selected plants was carried out in experiment II. Phytochemical screening study showed that selected plants contained volatile oils, tannins, alkaloids, saponins, flavonoids. Alkaloids and steroids were only detected in the aqueous extract of Euphorbia hirta. Toxicity evaluation also showed that based on liver enzyme and histopathology the herbal aqueous extracts were not toxic when administered 2,000 mg/kg body weight by the oral route. Experiment III was conducted to examine the effects of dietary Euphorbia hirta supplementation on growth performance, nutrient digestibilities, digesta pH and ileal microbial population. 600 one-day-old broilers (Cobb-500) were housed in 30 pens of 20 birds each until day 42. The dietary treatments were: (1) basal diet (control), (2) basal diet + 0.02 g/kg virginiamycin (VM), (3) basal diet + 1.5 g/kg acidifier (OrgacidsTM) (OA), (4) basal diet + 2.5 g/kg E. hirta (EH2.5), (5) basal diet + 5 g/kg E. hirta (EH5.0) and (6) basal diet + 7.5 g/kg E. hirta (EH7.5). The higher levels of E. hirta inclusion (7.5 g/kg) improved FCR of broiler chickens at 42 days of age. The highest AMEn and protein digestibility were observed in EH7.5 group. On day 21, the total aerobic bacteria counts in the ileum content of the EH2.5, VM and control groups were significantly higher (P<0.05) than the other groups. OA and VM supplementation significantly increased (P<0.05) Lactobacillus count at day 21 and the lowest Lactobacillus count was noted in the EH7.5 birds. At 42 days, feeding of EH2.5 promoted greater numbers of lactobacillus, to compare with other groups and the lowest Lactobacillus count was enumerated in the control birds. On day 21, except for ileum and cecumn, OA significantly reduced (P