SALMONELLA IN COMMERCIAL CHICKEN FEEDS IN DAR ES SALAAM

Abstract

Salmonella is one of important hazardous pathogens causing salmonellosis in both humans and animals. In Tanzania, commercial chicken farming is a rapidly growing industry and salmonellosis is a serious problem. A study on Salmonella was conducted in commercially produced chicken feeds from feed mills in Dar es Salaam, Tanzania between October 2015 and February 2016. The objective of the study was to estimate the prevalence of Salmonella contamination in commercial chicken feeds. Feed samples were collected from a total of 384 randomly selected feed bags of different types from six feed mills to estimate the contamination prevalence. Cultural and biochemical tests were performed for the presence of Salmonella in the samples. Antibiotic sensitivity test was determined for all isolates. The overall prevalence of Salmonella in the study was 22.1%. All Salmonella isolates were motile thus no Salmonella Gallinarum was isolated. The prevalence of Salmonella in broiler starter mash, broiler grower mash, broiler finisher mash and layers mash were confirmed to be 29.8%, 17.0%, 19.6% and 18.4% respectively and prevalence of Salmonella in batches 1 and 2 were 23.7% and 20.7% respectively. Prevalence of Salmonella contamination was 22.2%, 39.1%, 14.7%, 0.0%, 25% and 42.9% of the samples from feed mills named A, B, C, D, E and F respectively. Significantly higher (p = 0.001) prevalence of Salmonella contamination was seen in feed mill B. All 85 Salmonella isolates were analysed for sensitivity to eight commonly used antibiotics using disc diffusion method. The antibiogram pattern indicated that Salmonella isolates were highly sensitive to Ciprofloxacin (89.0%) with less sensitivity towards Amikacin (36.6%), Sulphamethoxazole/Trimethoprim (14.6%), Gentamicin (13.4%), Kanamycin (12.2%), Streptomycin (3.7%), Amoxycillin (1.2%) and Tetracycline (0.0%). The presence of Salmonella in commercial chicken feeds in Dar es Salaam presents a contamination hazard for both humans and Salmonella-free flocks, and therefore, calls for improvement of hygienic processing and handling of feeds for effective control measures. Concurrently, antibiotics sensitivity surveillance should be done frequently to monitor the development of resistance in the commonly used antibiotics.