Antibiotic residues in commercial layer hens in Khartoum State, Sudan, 2007-2008

Abstract

The prevalence of antimicrobial residues in table eggs produced in Khartoum State, Sudan was estimated and determined. All available producing layer farms in the state were sampled in April, June and August 2008. For each layer house three egg samples were randomly collected to increase the sensitivity of antimicrobial residue screening test detectability. In total, 933 egg samples were analyzed, collected from 175 layer farms (335 layer houses) in three periods of collection. An in-house residue detection test using Geobacillus stearothermophillus var calidolactis was the analytical procedure used for the analysis. Data were analysed using Survey Toolbox to calculate the true prevalence and confidence intervals. The proportion of layer farms with antimicrobial residues in April, June and August was 61.1%, 60.2% and 68.7% respectively. The proportion of layer houses affected in April, June and August were 56.0%, 54.1% and 57.1% respectively. The results showed insignificant variation among the three periods of the surveillance (p = 0.57). A census covering all three localities of the state (Khartoum, Bahry and Omdurman) was carried out in late 2007 and early 2008. Data were recorded on areas where farms occur, number of houses per farm, total capacity of birds and farming systems. The census showed that there were 252 layer farms in the state distributed in 31 different areas with a total population of 2 221 800 birds. A structured questionnaire survey was carried out in April 2008 in the state, to assess and collect data on risk factors associated with the presence of antimicrobial residues in table eggs. The questionnaire investigated antibiotic usage patterns for each layer farm as well as the basic knowledge and understanding of farmers about public health concerns associated with antibiotic use in food producing animals. Questions were closed ended and data was obtained through direct interviews with farm owners and managers. Descriptive statistical analysis was carried out on the information captured; calculating frequencies, graphs and measures of association, using the EpiInfo™ statistical package. Ninety two farms were surveyed 98% of which comprised open-sided houses. It was found that 48.9% of the farms surveyed were on antibiotic treatment when the survey was conducted, while 58.7% of the farms had used antibiotics within the last three months. There was a significant association between having disease on the farm and using antibiotics (P<0.001). The study showed that there is a serious lack of knowledge about the dangers of using antibiotics in animals and their potential impact on human health. In addition, Sudan lacks any type of formal control of veterinary drugs in terms of legislated residue limits or monitoring and surveillance programmes. This leads the authors to the conclusion that all Sudanese consumers are at risk for ARs in eggs.