Content and uptake of minerals in the yolk of broiler embryos during incubation and effect of nutrient enrichment

Although embryo and chicken growth and development rely on mineral nutrition, information on mineral levels in the egg compartments during incubation is limited. Accordingly, we examined P, Ca, Fe, Zn, Cu, and Mn levels in the yolk of breeder eggs during incubation and the effect of embryonic mineral (with specific nutrients) enrichment on yolk mineral levels and consumption. First, fertile eggs were examined on day of setting (DOS), embryonic day (E) 11, E13, E15, E17, E19, E20, and day of hatch (DOH) for the mineral content in the yolk (and albumen on DOS) by inductively coupled plasma atomic emission spectroscopy. Results showed that on DOS, the yolk is the major origin for Mn, P, Fe, Ca, Cu, and Zn. Interestingly, P, Fe, Zn, Cu, and Mn were mostly consumed from the yolk until E17, after which their consumption was very low. Consumption of P was constant until E17 and then decreased until E20. Consumption of Fe, Zn, Cu, and Mn was medium to mild until E11, increased between E11 and E17, and minimal between E17 and DOH. Enrichment treatment, where fertile eggs were divided into 2 groups [nonenriched (control) and enriched (with minerals, vitamins, and carbohydrates on E17 using the in ovo feeding method)] showed that the enriched group had higher Fe, Zn, Cu, and Mn levels than the nonenriched group and exhibited higher consumption of Fe, Zn, and Mn between E20 and DOH. Analysis of the shell mineral composition along incubation showed that the shell released low amounts of P, Fe, and Mn in comparison with the yolk mineral content. Therefore, we concluded that the shell is a minor source of these minerals. Studying the mineral resources and consumption of embryos can lead to a better understanding of the mineral limitations of embryos during incubation. Additionally, because minerals are important for the development of the embryo, the higher mineral levels and consumption observed in the enriched group may affect the development of critical organs, such as the skeletal system.