Evaluation of Ocimum gratissimum and Ocimum canum as natural growth promoters on the growth performance, intestinal microbiota and villi morphometry of broiler chickens

The study was carried out to evaluate the performance of broiler chickens fed diets containing Ocimum gratissimum and Ocimum canum as an alternative to antibiotic growth promoters (AGPs). A total of 396, one day-old Cobb 500 broiler chicks were randomly allotted to six dietary treatments each replicated thrice with 22 birds per replicate in a completely randomized design. Six treatment diets were formulated containing 0g of experimental materials as control, 400 and 800g of O. gratissimum (T2 and T3), 400 and 800g of O. canum (T4 and T5) while oxytetracycline as recommended by the manufacturer was used as positive control. Data were collected on growth parameters: initial weight, final weight, weight gain, feed intake and feed cost per kg gain at both the starter and finisher phases. All data collected were subjected to analysis of variance and significant differences among treatment means were compared using Tukey procedures. Growth performance result showed that final weight, weight gain, feed conversion ratio and feed cost per kg gain were significantly higher (p<0.05) for birds fed diets containing O. gratissimum and O. canum at 800g per 100kg diets at both the starter and finisher phases. The population of Bacillus and Lactobacillus spp. were increased while the concentration of Escherichia coli, Clostridium spp., Salmonella spp., Enterobacteriaeae and Pseudomonas spp were significantly (p<0.05) reduced by the inclusion of Ocimum spp. Villi area, villi perimeter, height, width, crypt depth and villi height/crypt depth ratio were higher (p<0.05) for birds fed dietary supplement of 400g of O. gratissimum, 400g and 800g of O. canum and AGP (Oxyteracycline) than the control. Addition of O. gratissimum and O. canum in broiler chickens' diets significantly improved growth performance, intestinal microbiota and villi morphometric. Farmers and feed millers can use O. gratissimum and O. canum at 800g/100kg diets for improved performance.