On-farm evaluation of aflatoxin binder inclusion in dairy feed as a strategy to reduce milk aflatoxin M1 contamination in the Rwandan context

Aflatoxins (AF), fungal metabolites, can contaminate feed in favorable environments, posing health risks to humans and animals. Dairy cows exposed to aflatoxin B1 (AFB1) excrete its metabolite, aflatoxin M1 (AFM1), in milk, compromising its safety. The current study examined the use of an AF binder in dairy feed concentrates on farms in Rwanda to mitigate AFM1 in milk. It was conducted in Nyagatare district, peri-urban areas of Kigali (Center), and Huye district (South) with 42 farmers randomly selected from a previous study evenly divided into control and intervention groups. The intervention group received an AF binder (Novasil™ Plus) and training on both the usage of the binder and AF prevention in dairy feed. Sociodemographic and dairy management data were collected through semi-structured questionnaires. Farmers in both the treatment and control groups were visited at regular intervals over a 3-month time period (five total visits per farmer) to collect samples of milk and feed for the quantification of AFM1 and AFB1, respectively, and to interview participants. The use of the AF binder evidenced a significant reduction in milk AFM1 contamination between the intervention (mean, 0.15 µg/l; median, 0.13 µg/l) and control groups (mean, 0.30 µg/l; median, 0.24 µg/l) (p < 0.05). AFB1 was detected in the feed concentrate at a mean concentration of 32.2 µg/kg (median, 36.2 µg/kg); however, mean AFM1 levels in both groups (i.e., control and intervention) did not exceed the Rwanda Standards Board (RSB) regulatory limit of 0.5 µg/kg AFM1. AF binders show potential as a low-cost strategy to reduce AFM1 contamination in the Rwandan context. However, there is a need for clear standards on the registration and use of binders before they are deployed in-country and to claim their mitigating effects on AFM1 in milk.