Egg shell quality in Japanese quail: characteristics, heritabilities and genetic and phenotypic relationships

Abstract

The objective of the present study was to estimate heritabilities as well as genetic and phenotypic correlations for egg weight, specific gravity, shape index, shell ratio, egg shell strength, egg length, egg width and shell weight in Japanese quail eggs. External egg quality traits were measured on 5864 eggs of 934 female quails from a dam line selected for two generations. Within the Bayesian framework, using Gibbs Sampling algorithm, a multivariate animal model was applied to estimate heritabilities and genetic correlations for external egg quality traits. The heritability estimates for external egg quality traits were moderate to high and ranged from 0.29 to 0.81. The heritability estimates for egg and shell weight of 0.81 and 0.76 were fairly high. The genetic and phenotypic correlations between egg shell strength with specific gravity, shell ratio and shell weight ranging from 0.55 to 0.79 were relatively high. It can be concluded that it is possible to determine egg shell quality using the egg specific gravity values utilizing its high heritability and fairly high positive correlation with most of the egg shell quality traits. As a result, egg specific gravity may be the choice of selection criterion rather than other external egg traits for genetic improvement of egg shell quality in Japanese quails.

Influence of selection for egg production on egg quality traits in Japanese quail

“…However, values lower than those observed in the current study were reported by Lotfi et al (2012), El-Tarabany et al (2015), and Sari et al (2016). Also, Narinc et al (2015) reported averages of 1.04 g and 8.17% for ESW and ESP.…”

“…In contrast, Sezer (2007) and Lotfi et al (2015) estimated the heritability for EW in Japanese quail to be 0.83 and 0.41, respectively. The heritability of ESI observed in this study was lower than the estimates of 0.51 and 0.38 reported by Sezer (2007) and Narinc et al (2015), respectively, whereas, Lotfi et al (2012) estimated a slightly lower heritability of 0.14 for ESI in quail eggs. The heritability estimates obtained in the present study were numerically higher than the estimates for EST, ESW, and ESP of 0.13, 0.15 and 0.09, respectively, from Lotfi et al (2012).…”

“…In the current study, the average value of ESI was high (78.72%), which might be because of the genetic selection programme. The current value is within the ESI range values of 76.29% and 80.45% that were reported in the literature (Sezer, 2007;Alkan et al, 2010;Nowaczewski et al, 2010;Daikwo et al, 2013;Narinc et al, 2015). In contrast, Kul and Seker (2004) reported an ESI value of 74.90%.…”

“…These findings are within the ranges for Japanese quail reported by Taha (2009), who found EN ranged from 51.97 to 72.83, and Fathi et al (2016), who observed average ENs of 57.0 and 65.8 eggs in the control and selected lines, respectively. The present study revealed that the average EW was 13.63 g. Khaldari et al (2010) and Copur et al (2010) reported similar averages of 13.40 g and 13.25 g. In contrast, lower EW with a range of 10.27 -12.76 g was reported for quails by Hassan et al (2003), Kul and Seker (2004), Sari et al (2016), Al-Daraji et al (2010), andNarinc et al (2015). Alkan et al (2010) recorded a higher EW with an average of 14.14 g in a high bodyweight line of Japanese quail.…”

“…Fathi et al (2016) revealed that selection for higher EN and lower broken eggshell percentage improved ultrastructural features of the mammillary layer rather than selection for EST. Narinc et al (2015) stated that specific gravity may be the selection criterion of choice for genetic improvement of eggshell quality. On the other hand, selection for higher egg numbers was predicted to reduce the thickness and strength of the eggshell (Lotfi et al, 2012).…”