Differences in the onset of puberty in female Japanese Quail divergently selected for adrenocortical responsiveness

MARIN R.H.; D. G. SATTERLEE

ARCHIVOS DE ZOOTECNIA

Asociación Iberoamericana de Zootecnia

Año: 2006 vol. 55 p. 195 - 202

0004-0592

Two quail lines have been selected for either a high or low plasma corticosterone response to brief mechanical restraint (HPCR or LPCR respectively). The present study assesses whether divergent selection altered the onset of puberty in females of HPCR, LPCR and a random-bred (RB, control) line. Egg production was monitored in 12 pens from each of the three lines (10 females in each pen) from the age at which the first egg was laid by any of the hens (44 days of age). Hen-day egg production (HDEP) was then calculated on a weekly basis for 10 wk of lay and the onset of puberty was assessed by calculation of the average ages at first egg lay and at 25% egg production. Age at first egg was elevated (p<0.05) in HPCR quail compared to controls (51.6 days vs. 49.4 days, respectively) while LPCR hens showed a value (50.0 days) intermediate to, and not statistically different from, the RB or the HPCR hens. Age at 25 % egg production was also elevated (p<0.05) in the HPCR line (67.4 days) than in the RB (62.7 days) while LPCR birds reach that index at an earlier age (60.9 days) than the other groups. Similar differences between groups were also reflected in their weekly HDEP means calculated in the first three weeks of lay. The present results suggest that the attainment of puberty would be either accelerated or compromised if a selection program included a low or high stress responsiveness phenotype respectively.