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Novel strategies that address vitamin A deficiency have been developed, such as high-carotenoid maize, a biofortified transgenic maize line rich in carotenoids generated by genetic transformation. The South African white maize inbred (M37W), which is devoid of carotenoids, was engineered to accumulate high levels of β-carotene (provitamin A), lutein, and zeaxanthin. Maize seeds contaminated with fumonisins and other mycotoxins pose a serious threat to both humans and livestock. During three consecutive harvests, the fungal incidence and the fumonisin and aflatoxin content of maize seeds grown in an experimental field in Catalonia (Northeastern Spain) were evaluated. Fungal infection was similar in high-carotenoid maize and its isogenic line, with Fusarium verticillioides being the most prevalent fungus in all the harvests. Neither Aspergillus spp. nor aflatoxin contamination was found. Fumonisin levels were lower in high carotenoid than in its isogenic line, but this reduction was statistically significant in only 2 of the 3 years of study. Our results suggest that high carotenoid content reduces fumonisin levels in maize grains. ; The study was supported by La Caixa (Recercaixa project PC084082 VitaMaize: high-quality and safe food through antioxidant fortified maize), the Agrotecnio Center, the Catalonian Government (2014 SGR 1296 Agricultural Biotechnology Research Group and XaRTA Reference Network on Food Technology) and the Spanish Ministry of Economy and Competitiveness (BIO2014-54441-P). J. Díaz-Gómez thanks the University of Lleida for a pre-doctoral grant. The authors would like to thank the Agricultural Biotechnology group of the University of Lleida, Antonio Michelena, and Jaume Lloveras for their work in the experimental field.

In many developing countries, maize is both a staple food crop and a widely-used animal feed. However, adventitious colonisation or damage caused by insect pests allows fungi to penetrate the vegetative parts of the plant and the kernels, the latter resulting in mycotoxin contamination. Maize seeds contaminated with fumonisins and other mycotoxins pose a serious threat to both humans and livestock. However, numerous studies have reported a significant reduction in pest damage, disease symptoms and fumonisin levels in maize hybrids expressing the Bacillus thuringiensis (Bt) gene cry1Ab, particularly in areas where the European corn borer is prevalent. When other pests are also present, the cry1Ab gene alone offers insufficient protection, and combinations of insecticidal genes are required to reduce damage to plants caused by insects. The combination of Cry1Ab protein with other Cry proteins (such as Cry1F) or Vip proteins has reduced the incidence of pests and, indirectly, mycotoxin levels. Maize hybrids expressing multiple Bt genes, such as SmartStax®, are less susceptible to damage by insects, but mycotoxin levels are not routinely and consistently compared in these crops. Bt maize has a greater economic impact on Fusarium toxins than aflatoxins. The main factors that determine the effectiveness of Bt hybrids are the type of pest and the environmental conditions, but the different fungal infection pathways must also be considered. An alternative strategy to reduce mycotoxin levels in crops is the development of transgenic plants expressing genes that protect against fungal infection or reduce mycotoxin levels by in situ detoxification. In this review article, we summarise what is known about the relationship between the cultivation of Bt maize hybrids and contamination levels with different types of mycotoxins. ; The authors are grateful for financial support from La Caixa (Recercaixa project VitaMaize: High quality and safe food through antioxidant fortified maize) and to the Catalonian Government (XaRTA Reference Network on Food Technology). The authors are also grateful to their research groups: Vegetal Products Technology (2014 SGR 540) and Agricultural Biotechnology (2014 SGR 1296). J. Díaz-Gómez thanks the University of Lleida for the predoctoral grant.

High-carotenoid (HC) maize, a biofortified staple crop which accumulates β-carotene, β-cryptoxanthin, lutein and zeaxanthin, was used as a feed component in a chicken feeding trial to assess the bioavailability of provitamin A (PVA) carotenoids in the kernel matrix compared to the synthetic and natural color additives routinely used in the poultry industry. We found that the PVA carotenoids in HC maize were not metabolized in the same manner: β-carotene was preferentially converted into retinol in the intestine whereas β-cryptoxanthin accumulated in the liver. We also considered the effect of zeaxanthin on the absorption of PVA carotenoids because zeaxanthin is the major carotenoid component of HC maize. We found that chickens fed on diets with low levels of zeaxanthin accumulated higher levels of retinol in the liver, suggesting that zeaxanthin might interfere with the absorption of β-carotene, although this observation was not statistically significant. Our results show that HC maize provides bioavailable carotenoids, including PVA carotenoids, and is suitable for use as a feed component. ; This work was supported by La Caixa (Recercaixa project PC084082 VitaMaize: High quality and safe food through antioxidant fortified maize), the Spanish Ministry of Economy and Competitiveness (BIO2014-54426-P; BIO2014-54441-P, FEDER funds), the Catalan Government (2014 SGR 1296 Agricultural Biotechnology Research Group) and the Agrotecnio Center.

Skin color in poultry is achieved by the addition of natural or synthetic pigments to feed. Crops used routinely in feed formulations offer an alternative cost-effective strategy to replace color additives if they are biofortified with sufficient levels of carotenoids. We tested the hypothesis that high-carotenoid (HC) maize, which was genetically engineered to accumulate high levels of β‐carotene, lutein and zeaxanthin in the endosperm, can replace carotenoid additives in poultry feed by performing two feeding trials using diets incorporating different maize lines with diverse carotenoid compositions: control (wild-type M37W, the parental line), HC, and standard yellow commercial maize supplemented with color additives (marigold flowers and red paprika extracts). The effects of dietary treatments on growth performance, health parameters, color evolution and carotenoid distribution were determined. We found that chickens fed on the HC diet grew normally and developed similar pigmentation to animals fed on a commercial diet supplemented with color additives, although yellowness was significantly higher in the commercial diet due to the high concentration of yellow xanthophylls. Lightness scores in chickens fed on the control, HC and commercial diets were 45.88 ± 1.31, 44.32 ± 1.10 and 44.29 ± 0.99, respectively, in breast muscle, and 51.62 ± 1.33, 49.66 ± 0.96 and 50.10 ± 1.16, respectively, in thigh muscle. Redness scores in chickens fed on the control, HC, and commercial diets were 0.36 ± 0.26, 3.25 ± 0.29 and 3.58 ± 0.29, respectively, in breast muscle, and 1.28 ± 0.37, 4.79 ± 0.39 and 4.85 ± 0.34, respectively, in thigh muscle. Yellowness scores in chickens fed on the control, HC, and commercial diets were 2.45 ± 0.47, 7.61 ± 0.64 and 9.66 ± 0.73, respectively, in breast muscle, and 3.38 ± 0.64, 10.00 ± 1.10 and 12.64 ± 0.97, respectively, in thigh muscle. High-carotenoid maize is therefore a cost-effective alternative to feed supplementation in the poultry industry. ; This work was supported by La Caixa (Recercaixa project PC084082 VitaMaize: High quality and safe food through antioxidant fortified maize), the Spanish Ministry of Economy and Competitiveness (BIO2014-54426-P; BIO2014-54441-P, FEDER funds) and the Catalan Government (2014 SGR 1296 Agricultural Biotechnology Research Group).

Biofortification is an effective and economical method to improve the micronutrient content of crops, particularly staples that sustain human populations in developing countries. Whereas conventional fortification requires artificial additives, biofortification involves the synthesis or accumulation of nutrients by plants at source. Little is known about the relative merits of biofortification and artificial fortification in terms of nutrient bioaccessibility and bioavailability, and much depends on the biochemical nature of the nutrient, which can promote or delay uptake, and determine how efficiently different nutrients are transported through the blood, stored, and utilized. Data from the first plants biofortified with minerals and vitamins provide evidence that the way in which nutrients are presented can affect how they are processed and utilized in the human body. The latest studies on the effects of the food matrix, processing and storage on nutrient transfer from biofortified crops are reviewed, as well as current knowledge about nutrient absorption and utilization. ; Research at the University of Lleida is supported by MINECO, Spain (BIO2014-54426-P; BIO2014-54441-P, FEDER funds), the Catalan Government (2014 SGR 1296 Agricultural Biotechnology Research Group) and Recercaixa. J. Díaz-Gómez thanks the University of Lleida for a pre-doctoral grant.