Abstract

Aloe vera has a long history as a medicinal plant with diverse therapeutic applications. This study was conducted to assess the antibacterial effect of Aloe vera gel extract against Escherichia coli and Salmonella enterica isolated from the gastrointestinal tract (GIT) of guinea fowls. The conventional method was used for the isolation of Escherichia coli and Salmonella enterica. The antibacterial activity of Aloe vera gel extracts (50, 100 and 200 mg/ml) and standard antibiotics were evaluated using the disk diffusion method. The prevalence of Escherichia coli in the GIT of the guinea fowls was 100% (15/15). All the Escherichia coli were susceptible to ciprofloxacin. At 48h and 72h of incubation, all the Escherichia coli were susceptible to gentamicin but not at 24h. Inhibition zones using the Aloe vera gel extract ranged from 7.87-12.23mm (50 mg/ml), 8.53-17.23mm (100 mg/ml) and 7.43-10.67mm (200 mg/ml) for Escherichia coli. Also, antibacterial test for Escherichia coli using the Aloe vera gel extract revealed an inhibition zone of 9.10-12.23mm for Escherichia coli isolate GIT1, 7.8-8.57mm for Escherichia coli isolate GIT2 and 7.43-17.23mm for Escherichia coli isolate GIT7. The prevalence of Salmonella enterica in the GIT of the guinea fowls was 40% (6/15). All Salmonella enterica were susceptible to gentamicin. At 48h and 72h of incubation, all the Salmonella enterica were susceptible to suphamethoxazole/trimethoprim and tetracycline but not at 24h. Inhibition zones using Aloe vera gel extract ranged from 7.13-12.57mm (50 mg/ml), 4.2-6.7mm (100 mg/ml) and 0-9.23mm (200 mg/ml). Furthermore, antibacterial test for Salmonella enterica using the Aloe vera gel extract revealed an inhibition zone of 5.3-12.57mm for Salmonella enterica isolate GIT9, 0-7.8mm for Salmonella enterica isolate GIT10 and 4.2-9.0mm for Salmonella enterica isolate GIT15. The study revealed that Aloe vera gel extract possessed antibacterial properties. Therefore, it can be added to the feed of guinea fowls as a prophylactic to reduce bacterial infections.