Direct and correlated responses to selection for 4-week body weight in two lines of Japanese quails

Abstract

Abstract. Data on 29,411 quails of two selected lines along with a control line were examined over nine generations. Significant genetic gains/generation for 4-week body weight were realized in the two strains (3.70 and 3.10 g). Significant correlated genetic changes were also observed in early body weights (day-old to 3-weeks) as well as in 16-week body weight. Egg number and sexual maturity did not show any significant response while egg weight and egg mass showed desirable genetic gains. Natural selection did not seem to exert any effect. Inbreeding levels of 0.32 to 0.43 % per generation did not appear to be of any significance in affecting the response. Realized heritabilities (0.21–0.24) were reasonably consistent between sexes and matched fairly well with the nine-generation pooled sire-component heritabilities of 0.20 ± 0.04 and 0.25 ± 0.04 in the two lines. There was evidence of maternal effects as indicated by excess of dam- over the sire-component heritability. Time-trend in heritabilities was non-significant. There was good agreement between the predicted and realized genetic gains.

Management of genetic diversity using gene dropping method based on pedigree information

“…In this study, the rate of inbreeding was 0.33 % in generation 2 up to 1.1 % in generation 4. This result is in agreement with Brah et al (2001) while it is in opposite with Biedermann et al (2009) that reported 4.62 % and 7.12 % at generation 2 and 3, respectively for a population of white park cattle. These high figures of inbreeding are due to the small number of population (11 males and 33 females).…”

Estimation of Additive and Non-Additive Genetic Variances of Body Weight, Egg Weight and Egg Production for Quails (Coturnix coturnix japonica) with an Animal Model Analysis

“…In general, the heritability values of the four body weight traits are higher for line 2 than for line 1. The estimated heritability of the body weight of the Japanese quail at different ages was reported, for example, by STRONG et al (1978), TOELLE et al (1991), BRAH et al (2001), SAATCI et al (2003, VALI et al (2005) andRESENDE et al (2005). These studies normally used body weights at different ages and often used different methods to estimate the heritability.…”

“…TOELLE et al (1991) used the simple full-sib analysis for their heritability estimates of the body weight from sire and dam components and reported values between 0.49 and 0.70. BRAH et al (2001) analysed data from 9 generations of two selected quail lines. They found heritability estimates of 4-week body weight between 0.35 and 0.56 using pooled estimates from sire and dam components.…”

Response to family selection and genetic parameters in Japanese quail selected for four week breast weight

“…Inbreeding depression has previously been reported for these traits (Khaldari et al 2010). Brah et al (2001) with the avoidance of mating between relatives reported Inbreeding levels of 0.32 to 0.43 % per generation that did not appear to be of any significance in affecting the response. Abplanalp (1967) reported that in quail populations three times more inbreeding depression for their entire reproductive cycle relative to domestic fowls can be observed, so in a closed population of quail a loss of 1 % hatchability would be sustained for every increase in the degree of inbreeding (about twice as severe as compared to chicken).…”

“…1999, Baylan et al 2009). Brah et al (2001) reported 9 generations of selection for 4 week body weight had increased the superiority of the selected strains over the control line to 44.2 and 35.9 %. Reddish (2004) reported that 6 generations of selection for pectoralis muscle weight resulted in 2.5 and 27 g improvement in pectoralis muscle weight and body weight in Japanese quail, respectively.…”