PERFORMANCE AND MOLECULAR IDENTIFICATION OF BACTERIA ISOLATED FROM THE GUT OF BROILER BIRDS AFTER ANTIBIOTIC ADMINISTRATION AND ENZYME SUPPLEMENTATION

Abstract

This study evaluated the effect of feed additives (antibiotic or enzyme) on performance and bacteria population in the ileum of one day – old broiler chicks (ANAAC 2000) randomly distributed to three treatments having eight replicates and ten birds per replicate. Completely randomized design was used and experiment lasted for 35 days.
Maize–soybean meal diet without antibiotic administration or enzyme supplementation served as control and was the same diet for all treatments. Antibiotic (Dicoxin plus ®) was administered to birds fed diet 2 and enzyme (Roxazyme G 2G ®) was supplemented to diet 3.Bacterial specific primers for rRNA gene sequences were used to amplify bacterial genes from samples and sequenced. Bacteria were identified from the gene sequences using Basic Local Alignment Search Tool (BLAST) against the National Centre for Biotechnology Information (NCBI).
Enzyme supplementation significantly (P<0.01) improved final Live body weight and weight gain compared to control or administration of antibiotic. The FCR was significantly enhanced (P<0.01) by enzyme and antibiotic supplementation. Lactobacillus acidophilus (L. acidophilus), Escherichia coli (E. coli) and Clostridia were identified in digesta sampled. Partial rRNA sequences identical to Clostridia were the lowest (1) in control and enzyme treatment. A value of 4 was recorded in antibiotic treatment. Lactobacillus acidophilus was numerically high in control (8) and enzyme treatment (5) compared to antibiotic administration (1). Partial rRNA sequences identical to Escherichia coli sequences was however high (48) in birds administered antibiotic compared to control (8) and enzyme treatment (9). Results indicated greater improvement in weight gain, FCR and Lactobacillus in broilers fed enzyme supplemented diet. Feed additives may affect the biodiversity of gut bacteria in poultry birds.