Visit to aquaculture farms in Uganda

Aquaculture is an important and growing industry worldwide, with developing countries like Uganda well-integrated into the global fish trade. Uganda produces up to 447,020 tonnes of fish from capture fisheries and aquaculture.

However, the increasing use of antibiotics in animals has raised global concerns about antimicrobial resistance. The World Bank estimates that increasing drug resistance could reduce global livestock production by 7.5 percent.

Fleming Fund fellow studying aquaculture

To better understand how, and to what extent antibiotics are used in aquaculture in Uganda, and to develop policies that effectively address the problem, Dr. Israel Mugezi, a veterinary inspector in the Ministry of Agriculture, Animal Industry and Fisheries is currently undertaking Fleming Fund fellow in  Animal Health Surveillance. 

Dr Mugezi is supported and mentored by Prof. Till Bachmann, Deputy Head of Infection Medicine at the University of Edinburgh, and Dr. Diego Robledo, Career Track Fellow in Aquaculture at the Roslin Institute.  

Aquaculture in Uganda

Due to the increasing demand for fish, there has been a shift from extensive to semi-intensive and intensive systems because they can provide higher yields. However, this intensification increases stocking density and nutrient pollution, which often leads to water quality problems. The combination of high stocking density and poor water quality increases the likelihood of pathogen outbreaks, which in turn can negatively impact the quality and speed of production and productivity.

One consequence of these higher disease rates in intensive agriculture is the reliance on antibiotics and other supplements, especially in countries where regulatory limits are not clearly defined or closely monitored, as is the case in Uganda.

Using antibiotics to treat fish

A significant factor contributing to increases in AMR is the selection of resistant microbes after the use of antimicrobials in the animal sectorDepending on the compounds used, fish excrete unmetabolised drugs or metabolites that can lead to contamination of the environment, including aquatic systems. Spread of resistance from the aquatic environment to humans can occur through consumption and handling of aquacultured foods, drinking water and direct contact with water or aquatic organisms. 

Survey of antibiotic use and knowledge in aquaculture farms

As part of his fellowship work, Dr Mugezi undertook a survey of antibiotic use and knowledge in aquaculture farms in central Uganda.

Dr. Mugezi selected 10 farms in different districts of Uganda based on available resources: 5 from Luwero district, 3 from Mukono district and 2 from Wakiso district. The objective of the study was to understand the extent of antibiotic use in aquaculture and to contribute to future policy direction on the use of antimicrobials in aquaculture in Uganda.

Antibiotics used to treat handling injuries

The main species of fish farmed was the tilapia, which has a greater local demand due to its small size, affordable to the majority of the population. There was limited use of antibiotics in the fish farms visited. Only one of the 10 fish farms visited used antibiotics during the production cycle.

Even when antibiotics were used, it was in response to transferring catfish fingerlings from one cage to another, resulting in pressure sores on the fish. Thus, the antibiotics were used in response to an injury, not as a pathogen. 

Fish mortality was mainly due to water quality problems that affected oxygenation, or injury during rearing and sorting. 

The ingredients of the fish feed used in the farms did not contain antibiotics in all the fish farms visited. The main ingredients of the fish feed are crude protein, fibre, and fat for fish pellets.   Another finding was the discharge of pond water into the surrounding wastewater systems, which can contaminate the surrounding water systems used by humans.

The AMU data collection in fish farms allowed me to apply my skills in digital questionnaire design, science communication, and data analysis using R. The activity gave me a good understanding of antibiotic use in fish farms, the economic benefits of fish farming with alternative feeds, and the market potential.

Dr Israel Mugezi

Recommendations based on data collection

It is still not clear how much of the fish reaching markets selling fish for human consumption, contains antibiotics. Future testing of fish sold is recommended to determine microbial load, and to assess to extent to which it poses a risk for antimicrobial resistance.

The study also highlighted the potential for contamination of local environment by water draining from fins farms.  This increases the risk of antibiotic leakage from farm into water sources used directly for human consumption.  Reservoir ponds should be available to collect drained pond water that can be disinfected before disposal to the environment.

Related links

Fleming Fund Fellowship Scheme

Prof Till Bachmann profile

Dr Diego Robledo profile

Aquaculture at the Roslin Institute