Boron (B) is a trace element that plays an important role in the mineral, cell membrane, hormone, and enzyme
metabolism of animals and humans. The aim of this study was to examine the effect of dietary calcium tetraborate
(CaB4O7) supplementation on the mineral composition of egg content and eggshell of laying quails. For this purpose, a
total of 20 male and 40 female quails, 6-week-old, were equally divided into 2 groups (control and additive groups) in
5 replicates (6 birds/replicate) and given CaB4O7 300 mg/kg feed in additive group. The experiment was conducted for
56 days. The eggs were collected and the mineral composition [B, calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe),
potassium (K), manganese (Mn), copper (Cu), zinc (Zn)] of egg content and eggshell samples were determined at the
end of the experiment in randomly collected 6 eggs per group. Results of this study indicated dietary supplementation
of CaB4O7 increased Mg (P<0.01), Na (P<0.01), and K (P<0.05) contents of edible parts of eggs compared to the control
group, but B concentration were not determined in edible parts of eggs in both groups. Moreover, B (P<0.01), Mg
(P<0.01), Na (P<0.01), Fe (P<0.01), K (P<0.05), Cu (P<0.05) and Zn (P<0.01) of eggshell were higher in the additive
group than control. There were also significant correlations between examined minerals both edible and eggshell parts
of the eggs. It may be concluded that supplementing diets with CaB4O7 could improve Ca metabolism, producing eggs
enriched in minerals, promoting B, Mg, Na, Fe, K, Cu, and Zn deposition in eggshells, and improving eggshells quality.
The effective B supplementation doses for functional egg production could be determined and B could be advantageous
in terms of beneficial physiological effects.