Long-Term Selection for Body Weight in Japanese Quail Under Different Environments

Abstract

Long-term selection was conducted for high 4-wk BW in Japanese quail under different selection environments to investigate selection limits and to determine whether genetic parameters for growth are similar to those in chickens. Quail lines were selected under an adequate 28% CP diet (P line) and under a low 20% CP diet (T line). Mean realized heritabilities ranged from 0.32 (T line) to 0.49 (P line) during the first 10 generations. Although genetic variation remained following 97 generations of selection, realized heritabilities obtained agreed with theoretical predictions of loss of additive genetic variability with continuous selection. Similarity of heritability estimates indicates that Japanese quail are an excellent model for genetic studies of growth in meat-type chickens. Positive relationships accompanying selection for high 4-wk BW were increases in adult BW, age at first egg, and egg weight. Negative relationships were decreases in percentage fertility and hatchability, and egg production. Increased growth rate in selected lines was accompanied by an increase in feed and water intake, and by improvement in feed efficiency. Feed efficiency differences appeared to be important only immediately following hatch, whereas feed intake differences were present from 0 to 4 wk. Evidence of major physiological changes accompanying selection for growth were not observed. However, changes were observed in increased "resource allocations" to supply organs, during late embryonic stages and the 1st wk posthatch. Carcass composition was similar between unselected and selected lines except for higher fat and lower moisture levels in selected lines.

Genetic association between sexual maturity and weekly live-weights in laying-type Japanese quail

“…Generally, the direct heritability estimates of live weights for males were higher than those of females. The heritability estimates in this study were similar to those reported by Michalska (1994), Marks (1996) and Schüler et al (1998), but were higher than those reported by Aggrey & Cheng (1994) and Saatci et al (2003). The heritability of the ASM was moderate and similar for males and females.…”

“…Knowledge of the heritability of traits is essential for understanding how individual characteristics change from one generation to another in response to selection (Falconer & Mackay, 1996). Studies of heritability have mostly focused on the estimation of genetic parameters for growth especially under different selection environments (Anthony et al, 1996;Marks, 1996;Saatci et al, 2003). However, selection rarely operates on only one characteristic at a time (Lande & Arnold, 1983).…”

Effect of selection for body weight in Japanese quails(Coturnix coturnix Japonica) on some production traits

“…The body weight differences between groups of generations were highly significant, except the parental generations (P<0.01). Previous selection studies also supported that the body weight of the populations significantly increased from the first generation (Marks, 1996;Oguz and Turkmut, 1999;Yolcu, 2005). The second generation female body weights for all groups were higher than male body weights.…”

“…Additionally, quails can be utilized for meat production within a month and mature at an early age of 6 weeks, such that female birds generally reach whole yield by approximately two months (Jatoi et al, 2013). The studies on Japanese quails generally focus on improvement of egg production in the early periods or the body weight of fixed age quails during short-and long-term selection programs (Marks, 1996;Yolcu, 2005;Minville, 2004;Narinc and Aksoy, 2012). To date, many selection studies have been performed in the fourth or fifth weeks of quails' body weight (Nestor et al, 1983;Marks, 1991;Antony et al, 1996;Oguz and Turkmut, 1999;Steigner et al, 1992;Khaldari et al, 2010).…”

Interleukin-15 responses to aging and unloading-induced skeletal muscle atrophy

“…Twenty-four young adult birds (2 mo) and 24 aged birds (24 mo) were examined in the present study. The lifespan of Japanese quails is ϳ26 -28 mo, and they are both physically and sexually mature by 1.5 mo of age (25,28). The PAT muscle is flexed with the wing on the birds back at rest, but it is stretched when the wing is extended.…”