Photoperiod-Induced Changes in Cloacal Gland Physiology and Testes Weight in Male Japanese Quail Selected for Divergent Adrenocortical Responsiveness

SATTERLEE, D. G.; MARIN R. H.

POULTRY SCIENCE

Poultry Science Association, Inc.

Año: 2004 vol. 83 p. 1003 - 1010

0032-5791

                In quail, activation of the hypothalamic-pituitary-adrenal axis has been linked to depression in the hypothalamic-pituitary-testicular axis, and cloacal gland development and foam production are known to be androgen dependent. Therefore, photoperiod manipulations that induce gonadal growth (long d) and involution (short d) were used to examine changes in cloacal gland physiology in male quail from lines selected for either a reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone response to brief restraint. Line differences in cloacal gland area (CAREA) and volume (CVOL), the proportion of individuals that produced cloacal gland foam (PICF), and the intensity of cloacal gland foam production (CFP) were initially assessed in adult males maintained on stimulatory, long photoperiods of 14 L: 10 D. Thereafter, these variables were re-examined weekly in the same males during their subsequent exposure to three wk of short d (6 L: 18 D) followed by return to long d for three more wk. Line differences in testes weight relative to body weight (RTW) were also measured at the end of the study. CAREA and CVOL were markedly greater in LS than HS males grown on long d. As expected, these indices of cloacal gland size were greatly reduced upon exposure to short d in both lines. However, line differences (LS > HS) in CAREA and CVOL were maintained during the first two wk of exposure to short d. Line differences in the depressed cloacal gland size measures were no longer evident by the third wk on short d as well as after the first wk of re-lighting wherein there were no further depressions in gland size of either line. However, by the end of two wk of re-photostimulation and thereafter, marked line differences (LS > HS) in CAREA and CVOL re-emerged. Photoperiod-induced line effects on CFP generally mimicked those of CAREA and CVOL. PICF was marginally different (P < 0.07) between the lines (LS > HS) only after one wk of light reduction. After 3 wk of re-photostimulation, RTW was nearly 25% greater in LS quail. The results suggest that selection for reduced adrenocortical responsiveness in Coturnix has resulted in certain reproductive advantages in middle-aged, adult males maintained on stimulatory photoperiods as well as in such adults subjected to photocastration and subsequent re-photostimulation.