Antimicrobial use and manure management practices among commercial chicken farmers in selected regions of Tanzania : gaps and strategies for mitigating antimicrobial resistance

Abstract

The intensification of commercial chicken production has increased antimicrobial use and manure generation, raising concerns about residues and resistant pathogens entering the environment. Use of raw chicken manure can introduce antimicrobial compounds and resistance determinants into agricultural soils. This study examined antimicrobial use and manure management practices among chicken farmers in Morogoro, Dar es Salaam, and Unguja, and identified key gaps in national regulatory frameworks and their on-farm implementation. A structured questionnaire was administered to 351 farmers to assess the types and usage of antimicrobials and manure handling practices. Farmers reported using fourteen antibiotic classes and four antiparasitic agents, with tetracycline being the most frequently used (54.1%). Most farmers in Unguja (97.7%), Dar es Salaam (87.3%), and Morogoro (70.9%) either apply manure as fertilizer, sell it, or both. A large proportion (93.2%) reported that they do not process manure before use or sale, mainly due to lack of technical knowledge (77.4%). Awareness of the health hazards posed by pathogens (43.3%) and drug residues (57.5%) is low. This study revealed critical gaps, including weak regulatory enforcement, inadequate surveillance systems, limited cross-sectoral integration, irrational antimicrobial use, and limited farmer awareness. Strengthening regulatory frameworks, improving farmer training, and promoting safer manure management methods are recommended to reduce the environmental dissemination of antimicrobial residues and resistance.

HIGHLIGHTS Public health relevance—How does this work relate to a public health issue? • Antimicrobial resistance (AMR) is a major global public health threat that compromises the treatment of infectious diseases. • Environmental exposure to antimicrobial residues and resistant bacteria through agricultural use of poultry manure represents an under-recognized pathway for AMR transmission. Public health significance—Why is this work of significance to public health? • Awareness may help to improve practices aiming to mitigate the spread of antimicrobial resistance, lowering the risk of hard-to-treat infections to humans and animals. • This paper provides recommendations for strategic interventions focusing on improving manure handling and antimicrobial use practices to reduce environmental contamination, thereby safeguarding community health. Public health implications—What are the key implications or messages for practitioners, policymakers and/or researchers in public health? • Promoting validated manure treatment methods such as composting could substantially reduce environmental AMR risks while supporting safe organic fertilizer use. • The findings highlight the need to integrate manure management into national AMR-frameworks and to enforce regulations requiring treatment of poultry manure before agricultural use.