caa a22 4500 397567588 CHVBK 20180308164832.0 cr unu---uuuuu 161202e199610 xx s 000 0 eng 10.3382/ps.0751198 doi (NATIONALLICENCE)oxford-10.3382/ps.0751198 MARKS H. L. USDA, Agricultural Research Service, Southeastern Poultry Research Laboratory, c/o The University of Georgia, 107 Livestock-Poultry Bldg., Athens, Georgia 30602-2772 Long-Term Selection for Body Weight in Japanese Quail Under Different Environments [Elektronische Daten] [H. L. MARKS] 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. © 1996 Poultry Science Association, Inc. Breeding and Genetics nationallicence Japanese quail nationallicence body weight nationallicence growth nationallicence long-term selection nationallicence genotype by environment interactions nationallicence Poultry Science Oxford University Press 75/10(1996-10), 1198-1203 0032-5791 75:10<1198 1996 75 ps https://doi.org/10.3382/ps.0751198 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0751198 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- MARKS H. L. USDA, Agricultural Research Service, Southeastern Poultry Research Laboratory, c/o The University of Georgia, 107 Livestock-Poultry Bldg., Athens, Georgia 30602-2772 NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/10(1996-10), 1198-1203 0032-5791 75:10<1198 1996 75 ps Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford