Plasma Constituents and Body Weights of Japanese Quail (Coturnix coturnix japonica) Selected for Twelve Generations for Plasma Cholesterol Responses to Adrenocorticotropin

Japanese quail were selected bidirectionally over 12 generations for plasma cholesterol (PC) responses to adrenocorticotropin (ACTH). In addition to the selected trait, plasma corticosteroids (PCS), triglycerides (PT), and glucose (PG) were measured before and after 3 daily injections of ACTH. The quail were also weighed at 31 days of age. By the 12th generation of selection, when measurements were expressed as deviations from the randombred control (C) line from which the selected lines had been derived, there was a difference in PC of approximately 55% between the high response (HR) and the low-response (LR) lines. Pre-ACTH PCS levels increased in all three lines over generations; however, relative to the C line, there was no difference between selected lines. The 3 days of ACTH injection depressed PCS levels. Relative to the C line, pre- and post-ACTH levels of PT were higher in the HR line than in the LR line, and the LR line declined linearly over generations. Levels of PG did not change over generation in the selected lines; however, pre-ACTH levels of PG tended to be higher in the LR line than in the HR line in all generations. Body weights of the HR line at 31 days remained almost exactly the same as the C line, but those of the LR line declined linearly over the 12 generations of selection. These studies demonstrated that the PC response to ACTH was moderately heritable (h2 approximately equal to .20).