The distribution of carotenoids in hens fed on biofortified maize is influenced by feed composition, absorption, resource allocation and storage.

Jose Antonio Moreno,José C E Serrano,Richard M Twyman,Manuel Portero-Otin,Joana Díaz-Gómez,Eduardo Angulo,Paul Christou,Gerhard Sandmann,Teresa Capell,Changfu Zhu,Carmina Nogareda

doi:10.1038/srep35346

Abstract

Carotenoids are important dietary nutrients with health-promoting effects. The biofortification of staple foods with carotenoids provides an efficient delivery strategy but little is known about the fate and distribution of carotenoids supplied in this manner. The chicken provides a good model of human carotenoid metabolism so we supplemented the diets of laying hens using two biofortified maize varieties with distinct carotenoid profiles and compared the fate of the different carotenoids in terms of distribution in the feed, the hen’s livers and the eggs. We found that after a period of depletion, pro-vitamin A (PVA) carotenoids were preferentially diverted to the liver and relatively depleted in the eggs, whereas other carotenoids were transported to the eggs even when the liver remained depleted. When retinol was included in the diet, it accumulated more in the eggs than the livers, whereas PVA carotenoids showed the opposite profile. Our data suggest that a transport nexus from the intestinal lumen to the eggs introduces bottlenecks that cause chemically-distinct classes of carotenoids to be partitioned in different ways. This nexus model will allow us to optimize animal feed and human diets to ensure that the health benefits of carotenoids are delivered in the most effective manner.

Highlights

Retinoic acid, a co-regulator of developmental gene expression[13]
Current feed supplements have a major impact on the downstream benefits of poultry products because egg yolks contain predominantly lutein and are poor sources of PVA carotenoids such as β-carotene, presumably because the latter are utilized by the hen[22]
We found that the uptake, distribution, metabolism and deposition of carotenoids was dependent on a range of factors that had a different impact on each type of carotenoid, such that some carotenoids were relatively depleted in the egg compared to the liver (e.g. β-carotene) whereas others were deposited in the egg against a concentration gradient, suggesting a specific transport mechanism

Summary

Introduction

Retinoic acid, a co-regulator of developmental gene expression[13]. Vitamin A deficiency is prevalent in developing countries and is an important health issue in developed countries, so any strategy to increase the PVA carotenoid content of food will be beneficial to society[14]. Vitamin A and carotenoid metabolism in chickens is closely related to the equivalent process in humans, so chickens are susceptible to vitamin A deficiency with similar symptoms[17,18] This suggests that chickens fed on carotenoid-enhanced diets may provide humans with nutritious meat and eggs, but may offer good models for the behavior of carotenoids in humans. The replacement of synthetic carotenoids and extracts with biofortified cereals could significantly reduce the costs of poultry feed while improving the health of chickens and passing those nutritional benefits to humans[7]. Current feed supplements have a major impact on the downstream benefits of poultry products because egg yolks contain predominantly lutein and are poor sources of PVA carotenoids such as β-carotene, presumably because the latter are utilized by the hen[22]. Carotenoids provided in biofortified cereals appear more accessible than retinol supplements in a commercial diet, which may provide a direct benefit to human consumers

Methods

Results

Conclusion