Interrelationships between Morphological, Densitometric and Mechanical Properties of Eggs in Japanese Quails (<i>Coturnix Japonica</i>)

Abstract

Eggshell quality in birds results from mineral density and composition determining its mechanical endurance. The aim of the study was to determine interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Twenty four eggs randomly collected from 17-week-old quails were subjected to morphological, denstiometric and mechanical evaluation using dual-energy X-ray absorptiometry (DEXA), quantitative computed tomography (QCT) and three-point bending test. Weight, height and width of eggs were positively correlated with the densitometric parameters obtained using DEXA (egg mineral density (EMD) and egg mineral content (EMC)) and QCT (total egg volume (TEvol) and total eggshell volume (TESvol)). Positive correlations were stated between TEvol and TESvol (r＝0.52; P＜0.05) and EMD and EMC r＝0.83; P＜0.05). Egg mineral density revealed positive correlations with TEvol and mean volumetric eggshell mineral density (MvESMD), while EMC was positively correlated with TEvol, TESvol and MvESMD (all P＜0.05). Eggshell breaking strength was positively correlated with MvESMD (r＝0.53; P＜0.05) and negatively correlated with eggshell thickness (r＝ −0.50; P＜0.05). In conclusion, the results obtained in this study showed numerous interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Both DEXA and QCT were shown to be valuable tools for evaluation of whole egg and eggshell quality with superior prognostic value of QCT for eggshell mechanical endurance prediction. The elaborated experimental model may serve for further investigations on physiological, pharmacological, environmental, nutritional and toxicological factors influencing egg quality.

Eggshell characteristics and cuticle deposition in three laying hen genotypes housed in enriched cages and on litter

“…Hence, the eggshell thickness was significantly affected by laying hen genotypes in spite of the non-significant effect on eggshell strength. This finding might be explained by Tatara et al (2016) who indicated that the mechanical endurance of the eggshell is not simply affected by its thickness but by other factors, e.g. mineral density, mineral content, and spatial micro architectural arrangement contribute to this characteristic.…”

Relationship between eggshell thickness and other eggshell measurements in eggs from litter and cages

“…These results are in agreement with Kibala et al (2015) who reported a positive genetic correlations between eggshell strength and its thickness. On the other hand, Tatara et al (2016) revealed a negative correlation between eggshell thickness and eggshell strength, indicating that mechanical endurance of the eggshell is not simply affected by its thickness but other factors such as mineral density, mineral content and spatial micro architectural arrangement contribute to this characteristic. Results of the present study indicated a significantly positive correlation between egg shape index and eggshell strength in both housing systems.…”

Eggshell structure, measurements, and quality-affecting factors in laying hens: a review

“…The authors observed a genetic correlation between eggshell strength and its thickness to be around 0.8, making shell thickness a selection index candidate element. Tatara et al (2016) used dual-energy X-ray absorptiometry, quantitative computed tomography, and three-point bending test and they found positive correlation between weight, height, and width of eggs and egg mineral content and egg volume. Moreover, the mean volumetric eggshell mineral density was positively correlated with eggshell breaking strength and negatively correlated with eggshell thickness.…”