Dietary calcium deficiency in laying ducks impairs eggshell quality by suppressing the process of shell biomineralization

Abstract

The objective of this study was to determine the effects of dietary calcium deficiency on the process of shell formation. Four hundred and fifty female ducks (Anas platyrhynchos) at 22 weeks were randomly assigned to three groups. Ducks were fed one of two calcium-deficient diets (containing 1.8% or 0.38% calcium, respectively) or a calcium-adequate control diet (containing 3.6% calcium) for 67 days (depletion period) and then all ducks were fed a calcium-adequate diet for an additional 67 days (repletion period). Compared with the calcium-adequate control, the average shell thickness, egg shell weight, breaking strength, mammillae density and mammillary knob thickness of shell from ducks that consumed the diet with 0.38% calcium were significantly decreased (P<0.05) during the depletion period, accompanied by reduced tibia quality. The mRNA expression of both secreted phosphoprotein 1 (SPP1) and carbonic anhydrase 2 (CA2) in the uterus was decreased after feeding calcium-deficient diets (1.8% or 0.38% calcium). mRNA transcripts of calbindin 1 (CALB1), an important protein responsible for calcium transport, and the matrix protein genes ovocalyxin-32 (OCX-32) and ovocleidin-116 (OC-116) were reduced in ducks fed 0.38% calcium but not 1.8% calcium. Plasma estradiol concentration was decreased by both of the calciumdeficient diets (P<0.05). The impaired shell quality and suppressed functional proteins involved in shell formation could be reversed by repletion of dietary calcium. The results of the present study suggest that dietary calcium deficiency negatively affects eggshell quality and microarchitecture, probably by suppressing shell biomineralization.

The Influence of Hen Aging on Eggshell Ultrastructure and Shell Mineral Components

“…Co 2+ is involved in bone formation and mineral deposition with ions such as Ca 2+ and F – ( Birgani et al, 2016 ). Decrease in the Ca concentration during aging reduces the thickness of the basal layer and the density of the mammillary knobs in eggshell formation ( Chen et al, 2015 ). In addition, decreasing concentrations of Ca and S not only induce crystallization of abnormal mammillary knobs but also negatively affect the binding to the eggshell membrane ( An et al, 2016 ).…”

Improvement of eggshell quality by dietary N-carbamylglutamate supplementation in laying chickens

“…The shape, size, and specific gravity of eggs; the thickness of the shell; and the distribution of material in the shell determine the strength of the eggshell. From the ultrastructure, palisade and mammillae layers of the eggshell are the thickest part ( Chen et al., 2015 ). The effective thickness of the mastoid layer is measured from the basal caps of the mammillary knobs to the point at which the palisade columns begin to fuse, and the width of the mastoid gap is the distance between the 2 basal caps of the mammillary knobs.…”

Nutritional requirements of meat-type and egg-type ducks: what do we know?

“…Therefore, providing inadequate amounts of Ca, P, and vitamin D, as well as neglecting their optimal relative ratios in poultry diets will lead to productivity problems and economic losses. For example, Ca deficiency in laying ducks reduces the egg production rate, egg weight, eggshell thickness, eggshell breaking strength, and Ca deposition in the eggshell as a result of decreased Ca levels in the plasma and shell gland, as well as downregulating the expression of genes related to Ca transportation and eggshell biomineralization [ 33 , 34 ]. In White Pekin and Mule ducks, Ca deficiency can lead to rickets, low growth rate, low feed utilization, and a high mortality rate [ 35 , 36 ].…”