Evaluation of Synbiotic Effect of Curry Leaf (Ocimum Canum) with Probiotic (Lactobacillus subtilis) on the Performance and Gut Morphology of Broiler Chickens

Abstract

The withdrawal of antibiotic growth promoters (AGPs) in poultry production due to antimicrobial resistance concerns has necessitated sustainable alternatives. This study evaluated the synbiotic effects of curry leaf (Ocimum canum) combined with probiotic (Lactobacillus subtilis) on the growth performance and gut morphology of broiler chickens. A total of 360 day-old chicks were randomly assigned to six dietary treatments in a completely randomised design with three replicates of 20 birds each. Treatment diets comprised: a control (no additives), Ocimum canum at 800 g/100 kg or 1200 g/100 kg, synbiotics (Ocimum canum at 800 g/100 kg or 1200 g/100 kg + Lactobacillus subtilis), and oxytetracycline (positive control). Data were collected on growth performance and villi morphometric traits. Results showed that the highest final body weight (953.42 g/bird), daily weight gain (32.69 g/bird/day), and best FCR (1.72) were recorded in birds fed diet containing oxytetracycline, and those fed diet containing 800 and 1200 g/100kg diet of Ocimum canum followed by group fed the synbiotic diet with 800 and 1200 g/100 kg O. canum plus L. subtilis. Feed cost per kilogram gain was lowest in the same group with similar trend. At the finisher phase, the highest final body weight (3221.57 g/bird), daily weight gain (110.32 g/bird/day), and best FCR (1.72) were recorded in birds fed the diet containing oxytetracycline, followed closely by those fed the synbiotic diet with 800 g/100 kg Ocimum canum plus L. subtilis (final body weight 3212.75 g/bird, daily weight gain 109.94 g/bird/day, FCR 1.74), and then the O. canum-only groups at 800 g/100 kg and 1200 g/100 kg. Feed cost per kilogram gain was lowest in the oxytetracycline and synbiotic (800 g/100 kg) groups. Hence, poultry farmers should incorporate Ocimum canum at 800 g/100 kg diet combined with Lactobacillus subtilis as a synbiotic feed additive to replace antibiotic growth promoters.