Growth hormone status and growth characteristics of Japanese quail divergently selected for four-week body weights.

A randombred line of quail (R1) and two lines selected for either increased (HW) or decreased (LW) 4-wk body weight were used to examine the relationship of growth to circulating growth hormone (GH) levels during growth. Differences in GH between males and females were not detected. Growth hormone was low at hatching in all lines but then increased to relatively high levels by the first post-hatching sample (3 to 7 days). A decline in GH then occurred in all lines, with low adult levels detected earlier in lines HW and R1 than in LW. The patterns of GH secretion and growth characteristics of lines HW and R1 were similar while those of LW were unique.