Genetic analyses of partial egg production in Japanese quail using multi-trait random regression models

Abstract

1. The aim of the present study was to estimate genetic parameters for average egg weight (EW) and egg number (EN) at different ages in Japanese quail using multi-trait random regression (MTRR) models. 2. A total of 8534 records from 900 quail, hatched between 2014 and 2015, were used in the study. Average weekly egg weights and egg numbers were measured from second until sixth week of egg production. 3. Nine random regression models were compared to identify the best order of the Legendre polynomials (LP). The most optimal model was identified by the Bayesian Information Criterion. A model with second order of LP for fixed effects, second order of LP for additive genetic effects and third order of LP for permanent environmental effects (MTRR23) was found to be the best. 4. According to the MTRR23 model, direct heritability for EW increased from 0.26 in the second week to 0.53 in the sixth week of egg production, whereas the ratio of permanent environment to phenotypic variance decreased from 0.48 to 0.1. Direct heritability for EN was low, whereas the ratio of permanent environment to phenotypic variance decreased from 0.57 to 0.15 during the production period. 5. For each trait, estimated genetic correlations among weeks of egg production were high (from 0.85 to 0.98). Genetic correlations between EW and EN were low and negative for the first two weeks, but they were low and positive for the rest of the egg production period. 6. In conclusion, random regression models can be used effectively for analysing egg production traits in Japanese quail. Response to selection for increased egg weight would be higher at older ages because of its higher heritability and such a breeding program would have no negative genetic impact on egg production.

Genetic analysis of egg production traits in turkeys (Meleagris gallopavo) using a single-step genomic random regression model

“…Estimates of genetic correlations between periods in the later stages of production were stronger than those between earlier stages, with estimates ranging from 0.94 to 0.99. Estimates of genetic correlations for later stages of production were also similar to those found in turkeys and quail [28]. These results show that variance components and genetic correlations between records at different weeks were less than 1 and changed over time.…”

Genetic Evaluation of Egg Production and Egg Quality Attributes in Japanese Quails through Partial Periods

“…Therefore, selection can be framed in terms of partial production periods (Poggenpoel et al 1996). This procedure enhances the overall production of eggs and may consequently results in greater genetic gain with decrease in the generation interval at each selection cycle (Lopes, 2005;Karami et al 2017).…”

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).…”