Ontogeny of Cloacal Gland in Male Japanese Quail Classified in a T-maze

LABAQUE, M. C.; SATTERLEE, D. G.; GUZMÁN, D. A.; MARIN, R. H.

POULTRY SCIENCE

POULTRY SCIENCE ASSOC INC

Año: 2007 vol. 86 p. 2013 - 2019

0032-5791

Broiler chicks that traverse a T-maze quickly to reinstate contact with their companions (HP, high performance) are known to grow faster, be more social, and exhibit a reduced plasma corticosterone response to acute stress than slower (LP, low performance) chicks. In quail of two genetically diverse lines, HP chicks showed and accelerated puberty and increased hen-day egg production. In the present study, the time course of sexual development in HP and LP male quail categorized in the T-maze at 2 d of age 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 (PICF), and the intensity of cloacal gland foam production (CFP) at 4, 5, 6, 7, 8, 9, 10, and 22 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. Body weight (BW) was also measured at the ages mentioned above and testes weight (TW) was registered only at the end of the study. CVOL relative to BW (RCVOL) was also calculated. Mean CAREA, CVOL and RCVOL were similar in HP and LP quail at 4 and 5 wk of age. Between 6 and 10 wk of age, those measurements were greater (P < 0.05) in HP than in LP quail. HP birds showed a trend to present a greater PICF than their LP counterparts at 5, 6, and 7 wk of age (P < 0.1 in all three cases). From 8 wk on, all birds (100%) were in foam production. CFP results mimicked those found for CAREA, CVOL, and RCVOL in that HP quail had higher CFP than LP quail between 6 and 10 wk of age; however, these group differences narrowly failed to reach significance at 6, 9 and 10 wk of age (P = 0.06 in all three cases) and were statistically significant at 7 wk of age. BW was significantly higher in HP compared to LP quail at 5, 6 and 7 wks of age. No significant differences were found in any of the variables measured at 22 wk of age. The results suggest that rapid negotiation of the T-maze by quail chicks is associated with accelerated puberty and growth in males. The enhanced reproductive development found in HP males do not remains extant throughout middle-age adulthood.   (Key words: light, short days, cloacal gland, corticosterone, Japanese quail)