Antimicrobial Residues in Cattle Tissues Processed at Slaughterhouses in Kilosa District, Morogoro, Tanzania

Abstract

The inappropriate use of antimicrobial drugs, limited knowledge among livestock stakeholders, and practices such as self-medication contribute to the accumulation of antimicrobial residues in edible animal tissues. This study aimed to investigate the presence of antimicrobial residues in cattle tissues using microbial screening methods at slaughterhouses in Kilosa District. A cross-sectional study was conducted from April to June in three wards: Kimamba, Dumila, and Kilosa. A total of 90 tissue samples, 30 each of muscle, liver, and kidney were collected. The samples were packaged in sterile polystyrene bags and transported to the laboratory at Sokoine University of Agriculture for analysis. Microbial inhibition methods were used to screen for the presence of antimicrobial residues. Data were analyzed using SPSS version 25. The chi-square test was employed to assess differences among tissue types, while Fisher’s exact test was used to evaluate associations. Overall, 28.9% (26/90) of the tissue samples tested positive for antimicrobial residues. Liver tissues showed the highest prevalence at 46.7% (14/30), followed by muscle tissues at 40.0% (12/30). No antimicrobial residues were detected in kidney samples. The differences in residues occurrence among the tissue types were statistically significant (p = 0.000). Residues occurrence in muscle tissues varied significantly by ward (p = 0.000), indicating a strong geographic influence. However, the distribution of residues in liver tissues did not show a statistically significant variation among wards (p = 0.314), suggesting a more uniform presence. These findings highlight the urgent need to strengthen regulatory frameworks, promote responsible antibiotic use in livestock production, and enhance surveillance systems. Addressing these issues is critical to protecting public health and combating the growing threat of antimicrobial resistance.