Cannabis poses heavy metal risks in traditional poultry feeds

This study examined three indigenous plant species used as feed additives in Central Uganda—Cannabis sativa, Capsicum frutescens, and Nicotiana tabacum—to evaluate their nutritional value and safety for poultry farming. Researchers analyzed these botanicals for protein content, minerals, antioxidants, and potentially harmful compounds including heavy metals like lead and cadmium. The results revealed significant nutritional variation among the plants, with Cannabis sativa showing the highest crude protein at 22.20% and exceptional levels of calcium and potassium, while Capsicum frutescens demonstrated the strongest antioxidant activity and highest caloric density.

However, the study uncovered a critical safety concern: both Cannabis sativa and Nicotiana tabacum accumulated lead and cadmium at levels exceeding FAO/WHO safety standards (lead >0.3 mg/kg). These heavy metal concentrations resulted in hazard indices above 1.0, indicating potential health risks for both the chickens consuming these feeds and ultimately for human consumers of the resulting meat and eggs. The heavy bioaccumulation of toxic metals suggests that while these plants offer genuine nutritional benefits, their use as feed additives requires strict limitations and processing methods to prevent contamination of the food chain.

Based on these findings, researchers recommend Capsicum frutescens as the safest option for integration into poultry feed, as it provided strong nutritional and antioxidant benefits without the heavy metal accumulation problem. The study highlights an important principle in agricultural practice: the presence of beneficial nutritional compounds does not guarantee safety for consumption, and traditional uses must be validated through rigorous testing before being promoted at scale. For regions relying on indigenous botanicals in agricultural systems, this research underscores the necessity of testing for environmental contaminants alongside nutritional profiling.