Genetic analysis of partial egg production records in Japanese quail using random regression models

Abstract

The main objectives of this study were to detect the most appropriate random regression model (RRM) to fit the data of monthly egg production in 2 lines (selected and control) of Japanese quail and to test the consistency of different criteria of model choice. Data from 1,200 female Japanese quails for the first 5 months of egg production from 4 consecutive generations of an egg line selected for egg production in the first month (EP1) was analyzed. Eight RRMs with different orders of Legendre polynomials were compared to determine the proper model for analysis. All criteria of model choice suggested that the adequate model included the second-order Legendre polynomials for fixed effects, and the third-order for additive genetic effects and permanent environmental effects. Predictive ability of the best model was the highest among all models (ρ = 0.987). According to the best model fitted to the data, estimates of heritability were relatively low to moderate (0.10 to 0.17) showed a descending pattern from the first to the fifth month of production. A similar pattern was observed for permanent environmental effects with greater estimates in the first (0.36) and second (0.23) months of production than heritability estimates. Genetic correlations between separate production periods were higher (0.18 to 0.93) than their phenotypic counterparts (0.15 to 0.87). The superiority of the selected line over the control was observed through significant (P < 0.05) linear contrast estimates. Significant (P < 0.05) estimates of covariate effect (age at sexual maturity) showed a decreased pattern with greater impact on egg production in earlier ages (first and second months) than later ones. A methodology based on random regression animal models can be recommended for genetic evaluation of egg production in Japanese quail.

Genetics and genomics of egg production traits in poultry species

“…A higher estimate of heritability (0.37) was reported by Narinc et al (2014a). Two studies (Khadiga et al, 2017;Karami et al, 2017) noted a decreasing trend in estimates of heritability for egg production with increasing age. Estimates of heritability for age at first egg were slightly higher, at 0.23 (Kaye et al, 2016), 0.21 (Khadiga et al, 2016), and 0.31 (Daikwo et al, 2014).…”

“…Quail refers to a large and diverse group of birds with breeds selected for eggs, meat, or dual-purpose production. Heritability of egg production in quail was estimated to be low (0.04-0.05; Silva et al, 2013;Kaye et al, 2016) or low to moderate if analyzed within periods of lay (0.03-0.16 for the UFV1 strain, and 0.2-0.25 for the UFV2 strain in Ribeiro et al (2017); 0.1-0.17 in Khadiga et al (2017); 0.04-0.09 in Karami et al (2017), and 0.11-0.14 in Lotfi et al (2012)). A higher estimate of heritability (0.37) was reported by Narinc et al (2014a).…”

Influence of Improved Microclimate Conditions on Growth and Physiological Performance of Two Japanese Quail Lines

“…The effects of sex and selection on the growth performance parameters were examined in the current study, the literature revealed differences between lines of various genetic backgrounds. The selection is a successful approach for quail performance and genetic enhancement, which may result in some alterations of physiological and metabolic processes that affect characteristics related to growth or egg production [ 30 , 31 , 32 , 33 ]. Since the growth trends of the sexes varied, females had significantly better BW and GR than males.…”

Modelling of growth alteration in Japanese quail after a selection experiment for body weight at 4 weeks of age

“…Genetic selection is a powerful method for genetic improvement of quail performance. It could alter some physiological relationships and metabolic processes either in growth (Farahat et al ., 2018) or egg production traits (Abou Khadiga et al ., 2017). Growth pattern varies among individuals due to genetic background (Narinç et al ., 2010 b ) and sex (Ojedapo and Amao, 2014).…”