Biofortified Black Beans (Phaseolus vulgaris L.) in a Maize and Bean Diet Provide More Bioavailable Iron to Chickens (Gallus gallus) Than Standard Black Beans

Abstract

Our objective was to compare the capacities of biofortified (88μg Fe/g) and standard (59μg Fe/g) black beans (Phaseolus vulgaris L.) to deliver Fe for hemoglobin (Hb) synthesis. Bean based diets (no added Fe) were formulated (dietary Fe concentrations were 39.4±0.2 and 52.9±0.9 mg/kg). Chicks were fed the diets for 6 wks (n=12) and Hb, feed‐consumption and BW were measured. Hb maintenance efficiency was different between groups on wks 2, 3 and 4 (P<0.05). Total body Hb‐Fe contents were different between standard (23.32±0.6 mg) and biofortified (25.50±0.8 mg) bean groups (P <0.05). Duodenal DMT1, DcytB, and ferroportin expressions were higher and liver ferritin was lower (P>;0.05) in standard vs. the biofortified groups. In‐vitro analysis showed no significant differences in Fe bioavailability between diets. The in vivo results suggested a relatively small nutritional benefit to the biofortified bean variety. Evidence suggests that the nutritional benefit of the biofortified beans is reduced by the presence of polyphenols. Hence, modification of the bean seed coat polyphenols may be a means to improve bean Fe bioavailability. We conclude that biofortified beans are a promising vehicle for increasing intakes of bioavailable Fe in populations that consume these beans as a dietary staple.Research support: HarvestPlus and USDA/ARS