Detection and quantification of aflatoxin b 1 in cultured Nile tilapia in Mvomero and Mbarali districts of Tanzania

MSc Thesis

This study was carried out to assess farmers’ awareness as well as to detect and quantify the levels of Aflatoxin B1 in Nile tilapia (Oreochromis niloticus) farms in Mbarali and Mvomero districts. A total of 36 farmers and extension workers were involved in a questionnaire survey. Ninety two samples, tilapia (n=62), fish feeds (n=10), organic manure (n=10) and pond water (n=10) were collected in February 2013 and assessed for Aflatoxin B1 by a competitive ELISA technique. About 44.4% of the respondents were aware of Aflatoxin B1. This toxin was found in all samples collected although the levels between the samples differed significantly (P < 0.05). Out of 92 samples collected, 7.6% showed Aflatoxin B1 concentration greater than 5.0 μg/kg. Also, out of 62 fish samples collected from both Districts, 98% were contaminated with Aflatoxin B1 while the remaining fish samples had Aflatoxin B1 concentration greater than maximum tolerable limit of 5.0 μg/kg set by TBS/FAO/WHO. The concentration of Aflatoxin B1 in manure and fish samples was significantly higher in contamination (p= 0.016, and 0.001, respectively at 95% C.I) in samples collected in Mvomero compared with those from Mbarali District. In conclusion, most farmers were not aware of aflatoxins or of measures to control the toxins in the field, which begins with good agricultural and handling practices (GAP/GHP). Aflatoxin B1 levels in fish were below the internationally acceptable limits for human consumption. The detection of small quantities suggest a need for extensive mycotoxin awareness creation and education program as well as the adoption of good agricultural practices that include proper storage and handling of feeds in Mvomero and Mbarali Districts.

Fisheries Education and Training Agency (FETA) and Enhancing Pro-poor Innovation in Natural Resources and Agricultural Value Chains Programme (EPINAV)