Potency of selected herbs on inhibition of ammonia producing bacteria
In effort to combat environmental pollution, improve animal production and avoid drug residue, producers have resorted to the use of phytobiotics to inhibit ammonia producing microbes in the gut. Freshly harvested Eucalyptus camaldulensis, Mangifera indica, Saccharum officinarum, Chromolaena odorata, Azadirachta indica and Carica papaya leaves were air dried, blended and extracted using five concentrations of solvent (100% water, 70% water + 30% methanol, 50% water + 50% methanol, 30% water + 70% methanol and 100% methanol). The antibacterial activities of the extracts and antibiotics (streptomycin and doxycycline) as control, were tested according to standard procedures against both gram positive (Bacillus subtilis, Staphylococcus aureus) and gram negative (Escherichia coli, Vibrio cholerae) ammonia producing bacteria. The inhibitory effect of 100% water, 70% water + 30% methanol and 30% water + 70% methanol extracts of Eucalyptus camaldulensis and Mangifera indica was not significantly different from that of streptomycin on all bacteria tested while doxycycline showed the lowest inhibitory activity. Saccharum officinarium extract from 30% water + 70% methanol and 100% methanol had significantly better inhibitory effect on Escherichia coli than the antibiotic drugs, Also, extract of Chromolaena odorata, Carica papaya and Azadirachta indica at 100% methanol had no significant difference from the inhibitory effect of antibiotics on Staphylococcus aureus, Vibrio cholera and Escherichia coli respectively. It can be concluded, therefore, that 100% methanol extraction of the herbs can be an effective alternative to synthetic antibiotics in reducing ammonia producing bacteria in animal production.