Cloacal Gland and testes Development in Male Japanese Quail Selected for Divergent Adrenocortical Responsiveness.

MARIN R. H.; SATTERLEE D. G.

POULTRY SCIENCE

Poultry Science Association, Inc.

Año: 2004 vol. 83 p. 1028 - 1034

0032-5791

The time course of sexual development in male quail from lines selected for either a reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone response to brief restraint was determined. Sexual development was assessed by examination of cloacal gland area (CAREA) and volume (CVOL), the proportion of individuals that produced cloacal gland foam, and the intensity of cloacal gland foam production (CFP) at 4, 5, 6, 8, 10, 14, and 16 wk of age. These intervals encompass ages during which growing, photo-stimulated quail would be expected to evolve from being totally prepubescent to well into adulthood. Testes weight (TW) and the proportion of individuals that had achieved a combined TW of 500 mg (PI500) were also measured at 6 and 16 wk of age. Mean CAREA and CVOL were similar in LS and HS quail at 4 wk of age. Beginning at 5 wk of age and thereafter, CAREA was greater (P < 0.05) in LS in than in HS quail. Similarly, beginning at 6 wk of age and thereafter, CVOL was greater (P < 0.05) in LS than in HS quail. More LS than HS birds also expressed foam at 4 (P < 0.05), 5 (P = 0.15), and 6 wk (P < 0.05). From 8 wk on, all birds were in foam production. CFP results mimicked those found for CAREA and CVOL in that LS quail had higher CFP than HS quail at all intervals of measurement; however, these line differences were not statistically relevant. TWs were higher (P < 0.02) in LS than HS quail when data from the two ages at which testes were harvested were combined. At 6 wk of age, the LS and HS birds showed a PI500 line difference (P < 0.08) of 1.0 and .91, respectively; by 16 wk, all birds exhibited a maximum PI500. The results suggest that: 1) selection for reduced adrenocortical responsiveness in Coturnix has been accompanied by an accelerated onset of puberty in males, and 2) enhanced reproductive development in LS males remains extant throughout early to middle-age adulthood.