Posts Tagged ‘Biofortification’

Zinc absorption from biofortified maize meets the requirements of young rural zambian children

Posted by gabrielamartinez on , in Journal Articles

56865Authors: Chomba, E.; Westcott, C.M.; Westcott, J.E.; Mpabalwani, E.M.; Krebs, N.F.; Patinkin, Z.W.; Palacios-Rojas, N.; Hambidge, K.M.

Published in: The Journal of Nutrition , 145: 514-519, 2015.


 

Background: The zinc content of maize, a major global food staple, is generally insufficient alone to meet the requirements of young children.
Objectives: The primary objective of this study was to determine whether substitution of biofortified maize (34 mg zinc/g grain) for control maize (21 mg zinc/g) was adequate to meet zinc physiologic requirements in young children for whom maize was the major food staple. A secondary objective was to compare total daily zinc absorption when maize flour was fortified with zinc oxide to a total concentration of 60 mg zinc/g.
Methods: Participants included 60 rural Zambian children with a mean age of 29 mo who were randomly assigned to receive 1 of 3 maize types (control, biofortified, or fortified) all of which were readily consumed (>100 g on 1 d). Total daily zinc intake (from maize and low-zinc relish) was determined from duplicate diet collections. Multiplication by fractional absorption of zinc, measured by a dual isotope ratio technique, determined the total daily zinc absorption on the day the test meals were given.
Results: The mean 6 SD total daily zinc intake (milligrams per day) from the biofortified maize (5.0 6 2.2) was higher (P < 0.0001) than for the control maize (2.3 6 0.9). Intake of zinc from the fortified maize (6.3 6 2.6) did not differ from the biofortified maize. Fractional absorption of zinc from control maize (0.28 6 0.10) did not differ from the biofortified maize (0.22 6 0.06). Total daily absorption of zinc (milligrams per day) from the biofortified maize (1.1 6 0.5) was higher (P = 0.0001) than for the control maize (0.6 6 0.2), but did not differ from the fortified maize (1.2 6 0.4).
Conclusions: These results indicate that feeding biofortified maize can meet zinc requirements and provide an effective dietary alternative to regular maize for this vulnerable population. This trial was registered at clinicaltrials.gov as NCT02208635. J Nutr 2015;145:514–9.

Maize genotype and food matrix affect the provitamin a carotenoid bioefficacy from staple and carrot-fortified feeds in Mongolian gerbils (Meriones unguiculatus)

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Agricultural and Food Chemistry 62 (1) : 136-143, 2014

Schmaelzle, S.; Gannon, B.; Crawford, S.; Arscott, S.A.; Goltz, S.;Palcios-Rojas, N.; Pixley, K.V.; Simon, P.W.; Tanumihardjo, S.A.

Biofortification to increase provitamin A carotenoids is an agronomic approach to alleviate vitamin A deficiency. Two studies compared biofortified foods using in vitro and in vivo methods. Study 1 screened maize genotypes (n = 44) using in vitro analysis, which demonstrated decreasing micellarization with increasing provitamin A. Thereafter, seven 50% biofortified maize feeds that hypothesized a one-to-one equivalency between β-cryptoxanthin and β-carotene were fed to Mongolian gerbils. Total liver retinol differed among the maize groups (P = 0.0043). Study 2 assessed provitamin A bioefficacy from 0.5% high-carotene carrots added to 60% staple-food feeds, followed by in vitro screening. Liver retinol was highest in the potato and banana groups, maize group retinol did not differ from baseline, and all treatments differed from control (P < 0.0001). In conclusion, β-cryptoxanthin and β-carotene have similar bioefficacy; meal matrix effects influence provitamin A absorption from carrot; and in vitro micellarization does not predict bioefficacy.

Biofortification strategies to increase grain zinc and iron concentrations in wheat

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Cereal Science, 2013

Velu, G.; Ortiz-Monasterio, I.;Cakmak, I.; Hao, Y.; Singh, R.P.

Micronutrient deficiencies, especially those arising from zinc (Zn) and iron (Fe), pose serious human health problems for more than 2 billion people worldwide. Wheat is a major source of dietary energy and protein for the world’s growing population, and its potential to assist in reducing micronutrient-related malnutrition can be enhanced via integration of agronomic fertilization practices and delivery of genetically-manipulated, micronutrient rich wheat varieties. Targeted breeding for these biofortified varieties was initiated by exploiting available genetic diversity for Zn and Fe from wild relatives of cultivated wheat and synthetic hexaploid progenitors. The proof-of-concept results from the performance of competitive biofortified wheat lines showed good adaptation in target environments without compromising essential core agronomic traits. Agronomic biofortification through fertilizer approaches could complement the existing breeding approach; for instance, foliar application of Zn fertilizer can increase grain Zn above the breeding target set by nutritionists. This review synthesizes the progress made in genetic and agronomic biofortification strategies for Zn and Fe enrichment of wheat.

Formation of heterotic groups and understanding genetic effects in a provitamin a biofortified maize breeding program

Posted by Carelia Juarez on , in Journal Articles

Published in Crop Science, 2013

Willy B. Suwarno, Kevin V. Pixley, Natalia Palacios-Rojas, Shawn M. Kaeppler and Raman Babu

Developing biofortified maize cultivars is a viable approach to combat the widespreadproblem of vitamin A deficiency among people for whom maize is a staple food. To enhance CIMMYT?s provitamin A maize breeding efforts, this study: 1) evaluated whether separation of experimental maize lines into groups based on maximizing their molecular-marker-based genetic distances (GD) resulted in heterosis for among-group crosses, 2) assessed genetic effects (general and specific combining ability, GCA and SCA) for grain yield and provitamin A concentrations in hybrids among 21 inbred lines representing the three proposed groups, and 3) assessed the association between grain yield and provitamin A concentrations. The lines were crossed following a partial diallel design resulting in 156 hybrids which were evaluated at four environments with two replications of one-row plots. The first plant in each plot was self-pollinated to produce grain for provitamin A analysis. Significant but small yield advantage of among versus within group crosses (0.47 Mg ha-1 21 , P<0.05) suggested that the groups identified by maximizing GD could be a practicalstarting point for further breeding work to develop useful heterotic groups. Furthermore, the GD-proposed heterotic groups were improved by later revising some line assignments to groups using estimates of SCA effects. GCA effects were significant (P<0.01) for all traits, whereas SCA effects were weak (P<0.05) or not significant for provitamin A carotenoid concentrations, indicating that these were controlled primarily by additive gene action. Grain yield was not significantly correlated with provitamin A concentration, indicating that both traits could be improved simultaneously.

Genetic variability for kernel B-carotene and utilization of crtRB1 3’TE gene for biofortification in maize (Zea mays L.)

Posted by Carelia Juarez on , in Journal Articles

Published in Indian Journal of Genetics and Plant Breeding 72 (2) : 189-194, 2012

M.  Vignesh, Hossain Firoz, T. Nepolean, Saha Supradip, P.K. Agrawal, S.K. Guleria, B.M. Prasanna and H.S. Gupta

Carotenoids are the major sources of dietary precursor of vitamin A and act as potential antioxidant besides preventing diseases such as night blindness in humans. Vitamin A deficiency is a global problem, but is particularly prevalent in developing countries like India, where 31 percent of pre-school children are reportedly affected. Evaluation of genetic variability for kernel β-carotene in 105 maize inbreds of diverse pedigree from India- and CIMMYT-origin revealed significant variation ranging from 0.02 to 16.50 μg/g. One of the key reasons for wide variation of kernel β-carotene is due to the allelic variation at crtRB1 3’TE gene. Five among 95 inbreds possessed the favourable crtRB1 3’TE allele with a mean β-carotene concentration of 0.86 μg/g. In contrast, the same allele detected in 20 CIMMYT-Maize HarvestPlus genotypes contributed a mean kernel-carotene concentration of 11.29 μg/g. The contrast in β-carotene concentration in Indian and CIMMYT genotypes could be attributed to the presence of SNPs and InDels in crtRB1 3’TE locus, along with the presence/absence of favourable alleles of other important genes influencing the carotenoid biosynthetic pathway. Marker-assisted breeding has been initiated, to introgress the crtRB1 3’TE favourable allele using high carotene CIMMYT inbreds as donors, to develop provitamin A-rich maize cultivars suitable for maize growing regions in India.

 

Performance of biofortified spring wheat genotypes in target environments for grain zinc and iron concentrations

Posted by Carelia Juarez on , in Journal Articles

Published in Field Crops Research 137 : 261-267, 2012

G. Velu, R.P. Singh, J. Huerta-Espino, R.J. Peña, B. Arun, A. Mahendru-Singh, M. Yaqub Mujahid, V.S. Sohu, G.S. Mavi, J. Crossa, G. Alvarado, A.K. Joshi and W.H. Pfeiffer

Genetic biofortification to improve zinc (Zn) and iron (Fe) concentrations in bread wheat (Triticum aestivum L.) could reduce micronutrient malnutrition-related problems in the developing world. A breeding program on wheat was started to enhance Zn and Fe concentrations and other essential traits needed in a successful commercial variety. The first set of advanced lines derived from crosses of high yielding wheats with genetic resources possessing high Zn and Fe such as Triticum spelta, landraces and synthetic wheat based on Triticum dicoccon were tested at nine locations in South Asia and Mexico for Zn and Fe concentration, grain yield and other traits. Analyses of variance across locations revealed significant genotypic, environmental and genotype × environment (G × E) effects for grain Zn and Fe concentrations and grain yield. Variances associated with environmental effects were larger than the genotypic and G × E effects for all three traits, suggesting that environmental effects have relatively greater influence. Although G × E interaction was significant, high heritabilities were observed for Zn and Fe concentrations at individual sites and across environments, reflecting non-crossover type of interaction. This trend was confirmed by the high genetic correlations between locations that showed similar ranking of entries across locations, indicating that it is possible to select the best adapted entries with high Zn and Fe concentration. Pooled data across locations showed increments of 28% and 25% over the checks for Zn and Fe. A considerable number of entries exceeded intermediate to full breeding target Zn concentrations, indicating that it is possible to develop Zn-biofortified varieties with competitive yields and other farmer preferred agronomic traits. The positive and moderately high correlation between Zn and Fe concentration suggest good prospects of simultaneous improvement for both micronutrients.

Energy-dispersive X-ray fluorescence spectrometry as a tool for zinc, iron and selenium analysis in whole grain wheat

Posted by Carelia Juarez on , in Journal Articles

Published in Plant and Soil, 2012

Nicholas G. Paltridge, Paul J. Milham, J. Ivan Ortiz-Monasterio, Govindan Velu, Zarina Yasmin, Lachlan J. Palmer, Georgia E. Guild and James C. R. Stangoulis

Background and aims

Crop biofortification programs require fast, accurate and inexpensive methods of identifying nutrient dense genotypes. This study investigated energy-dispersive X-ray fluorescence spectrometry (EDXRF) for the measurement of zinc (Zn), iron (Fe) and selenium (Se) concentrations in whole grain wheat.

Methods

Grain samples were obtained from existing biofortification programs. Reference Zn, Fe and Se concentrations were obtained using inductively coupled plasma optical emission spectrometry (ICP-OES) and/or inductively coupled plasma mass spectrometry (ICP-MS). One set of 25 samples was used to calibrate for Zn (19–60 mg kg–1) and Fe (26–41 mg kg–1), with 25 further samples used to calibrate for Se (2–31 mg kg–1 ). Calibrations were validated using an additional 40–50 wheat samples.

Results

EDXRF limits of quantification (LOQ) were estimated as 7, 3 and 2 mg kg–1 for Zn, Fe, and Se, respectively. EDXRF results were highly correlated with ICP-OES or -MS values. Standard errors of EDXRF predictions were ±2.2 mg Zn kg–1, ±2.6 mg Fe kg–1, and ±1.5 mg Se kg–1.

 

 Conclusion

 EDXRF offers a fast and economical method for the assessment of Zn, Fe and Se concentration in wheat biofortification programs.

The usefulness of iron bioavailability as a target trait for breeding maize (Zea mays L.) with enhanced nutritional value

Posted by Carelia Juarez on , in Journal Articles

Published in Field Crops Research 123(2): 153-160, 2011

The usefulness of iron bioavailability as a target trait for breeding maize (Zea mays L.) with enhanced nutritional value

Kevin V. Pixley, Natalia Palacios-Rojas and Raymond P. Glahn

Iron (Fe) deficiency is the most widespread nutritional problem, affecting as many as half of the world’s population. Only a small fraction (2–15%) of Fe from plant sources is typically bioavailable, that is, available for absorption and nutritionally useful for humans. This study evaluated Fe concentration and bioavailability for three diverse sets of 12, 14 and 16 maize hybrids grown in two- or three-location trials to assess the feasibility of selecting for Fe bioavailability in breeding programs. Bioavailability of Fe, assessed using the in vitro digestion/Caco-2 cell model, varied significantly among hybrids in two of the three trials. Location effects were larger than location by genotype interaction effects, additive but not non-additive gene action was significant, and heritability estimates were mostly between 0.55 and 0.65 for Fe bioavailability estimators. Bioavailability of Fe was not associated with Fe concentration in grain or with grain yield. Negative correlation of Fe bioavailability with zinc concentration in grain for one of the three hybrid trials, and positive correlation with provitamin A concentrations in one trial were indicative of inhibitor and enhancer effects on Fe bioavailability, respectively. Although use of the Caco-2 cell model is promising, particularly because it integrates the whole meal, or food matrix effect on Fe bioavailability, the complex nature of the assay and moderate heritability of bioavailability estimators make it most suitable as an intermediate selection tool, following high throughput selection for molecular markers of Fe bioavailability, currently in development by other researchers, and preceding validation and efficacy trials with animal and human models.

 

 

How cost-effective is Biofortification in combating micronutrient malnutrition? An Ex ante assessment

Posted by on , in Journal Articles

Published in World Development 38(1):64-75, 2010

How Cost-Effective is Biofortification in Combating Micronutrient Malnutrition? An Ex ante Assessment

J.V. Meenakshi, Nancy L. Johnson, Victor M. Manyong, Hugo DeGroote, Josyline Javelosa, David R. Yanggen, Firdousi Naher, Carolina Gonzalez, James García and Erika Meng

Biofortification is increasingly seen as an additional tool to combat micronutrient malnutrition. This paper estimates the costs and potential benefits of biofortification of globally important staple food crops with provitamin A, iron, and zinc for twelve countries in Africa, Asia, and Latin America. Using a modification of the Disability-Adjusted Life Years framework we conclude that overall, the intervention can make a significant impact on the burden of micronutrient deficiencies in the developing world in a highly cost-effective manner. Results differ by crop, micronutrient, and country; and major reasons underlying these differences are identified to inform policy.