Efficacy of selected chemical and biological binders in reducing aflatoxin concentrations in poultry feeds
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To support the massive increase in poultry production in Uganda, there is need to improve the quality of feed in terms of nutrient composition and absence of harmful and toxic materials. Feed can be contaminated by aflatoxins that are major carcinogens due to farmers poor agricultural practices coupled with the favorable climate which favors their growth. Aflatoxins lead to decreased feed intake, weight gain, immune suppression, lowered reproductive efficiency, decline in egg production and increased mortality rates. Use of biological and chemical aflatoxin binders is one way of increasing the safety of the feed. The major advantages of using binders to remove the toxins from the feed include low cost, safety and the ease of addition to the animal feed. This study investigated the efficiency of biological (bacteria, yeast and their combination) and chemical (bentonite) binders in decreasing aflatoxin concentrations in poultry feed. Bentonite (0.3% w/v), yeast and bacteria (1×108 CFU/mL) each were added to the aflatoxin spiked and non-spiked feed. Feed was spiked with 40 μg/L of aflatoxins. Methanol solution (80%) was used for extraction of the aflatoxins. Quantification of aflatoxins was carried out using fluorimetry. Bentonite showed the highest efficiency of 93.43 ± 0.01% followed by the yeast isolate with 83.64%; then a combination of bacteria and yeast with 77.85%. The bacterial isolate gave the least binding efficiency with 74.94% aflatoxin adsorption. Temperature, pH and the feed matrix significantly affected the efficiency of the binders (p < 0.001). Aflatoxin reducing activity of the binders was lower in presence of feeds as compared to activity in Phosphate Buffered Saline. Bentonite in presence of feed produced a decrease in AFB1 concentrations of 93.4 ± 0.01% which is lower than that in PBS of 96.1±0.01%. The binding capacity of the binders was more favored by temperatures of 37°C and 42°C compared to room temperature. Bentonite at pH 4.5 produced a percentage reduction of 93.3±0.01% whereas at pH 6.5, a percentage of 95.4 ± 0.005%. For bacteria, at pH 4.5, a percentage of 74.9 ± 0.003% was produced whereas at pH 6.5 a percentage of 73.6 ± 0.005% was obtained. The data adduced showed that bentonite, yeast and the bacterial strains investigated in this study are very promising strategies for counteracting AFB1 in poultry feed. Therefore there is need for further investigation on their binding capacity in in vivo studies.