Abstract

A cross sectional study was conducted between November, 2011 and April, 2012 to determine the prevalence and risk factors associated with Salmonella infection among chicken flocks in Jimma town, Ethiopia. Management system, sex, season, age and breed of the chicken flocks examined in the study were considered as risk factors and evaluated whether they are associated with Salmonella infection or not. A bacteriological examination was carried out on 384 faecal samples originated from 232 exotic chicken flocks which were kept indoors and 152 local chicken flocks which were free ranging. The faecal samples were enriched with peptone water for 24 h and then seeded on the selective enrichment media, Rappaport Vassiliadis Soy Broth and incubated at 37°C for 24 h. Following selective enrichment, 0.1 ml of the pre enriched broth of the various dilutions were streaked aseptically into Xylose Lysine Desoxycholate (XLD) agar plates and incubated at 37°C for 24 h. Presumptive identification of Salmonella was done based on morphology and colour of the colonies on the culture media. Final identification and assignment of Salmonella was conducted by employing biochemical tests such indole production, citrate utilization and urease tests. The identification result proved the overall prevalence of Salmonella to be 41.9%. The prevalence of Salmonella infection were found to be higher in indoor chickens (42.7%) than chickens that were kept as free ranging (40.8%) but there was no statistically significant difference (p>0.05) on the prevalence ofSalmonella infection in chicken flocks between management systems. The prevalence ofSalmonella in female chicken flocks (43.0%) was higher than in male chicken flocks (39.0%) and there was no statistical significant difference (P>0.05) on the prevalence ofSalmonella between sexes. The highest prevalence of Salmonella was recorded during spring (47.7%) followed by autumn (39.7%) and the lowest prevalence of Salmonellainfection among chicken flocks was seen during winter (36.8%). Statistical analysis of the data showed that there was no statistical significant difference (P>0.05) on the prevalence of Salmonella in chicken flocks among seasons. Layers and cocks were proved to be highly infected with Salmonella (46.2%) followed by broilers (41.3%). The lowest prevalence of Salmonella infection was seen in chickens (40.8%). There was no statistical significant difference (P>0.05) on the prevalence of Salmonella in chicken flocks among ages. The prevalence of Salmonella was proved to be higher in exotic breed chicken flocks (42.7%) than chicken flocks which were kept as free ranging (40.8%). Analysis of the data showed there was no statistical significant difference (P>0.05) on the prevalence of Salmonella among chicken flocks between breeds. The prevalence of Salmonellaamong chicken flocks in Jimma town, Ethiopia, was proved to be very high. Hence, strengthening the knowledge, attitude and practice of chicken flock owners must be inaugurated in the area to mitigate the economic losses which could arise due toSalmonella infection in chicken flocks.

Key words: Salmonella, prevalence, chicken flocks, Jimma town, Ethiopia.