Bacterial flora of cockroach nymph fed garlic (Allium sativum) powder

Abstract

The increased cost of fishmeal in compounding fish feed has prompted the use of cheaper and readily accessible animal protein (insect protein). The effects of garlic powder supplement in diets fed to the 3^rd nymphal stages of Blattodea germanica and Supella longipalpa on bacterial activities were studied. Adult cockroaches with eggs were collected from Lapai town and reared under laboratory conditions for 10 weeks. The nymphs were stocked in groups of 50 nymphs each per replication in plastic containers. The cockroaches were fed formulated diets; A (Diet D plus 0.1 g garlic meal); B (Diet D plus 0.2 g garlic meal), C(Diet D plus 0.3 g garlic meal); D (experimental control; carrot, lettuce, milk, sorghum, flour and yeast); E (standard control; cabin biscuit)) during the study period. At the end of the experiment, cockroaches were sacrificed and assay for the bacterial population on the external body surface and in the gut. The bacteria load on the body surface of B. germanica ranged from 4.77 ± 0.15 to 9.50 ± 0.25 CFU/ml, while bacterial load in the gut ranged from 5.57 ± 0.29 to 9.80 ± 0.06 CFU/ml. Similarly, bacterial load in S. longipalpa ranged from 4.53 ± 0.32 to 9.57 ± 0.28 CFU/ml, while those of the gut ranged from 5.70 ± 0.25 to 9.33 ± 0.15 CFU/ml. Isolates identified include; Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Bacillus
spp., Streptococcus spp., Salmonella spp., Shigella spp. and Staphylococcus aureus. This study supports the use of garlic as an effective antibacterial agent.