Ontogeny of the cloacal gland in male Japanese quail classified in a T-maze.
Broiler chicks that traverse a T-maze quickly to reinstate contact with their companions (HP, high performers) are known to grow faster, are more social, and have a reduced plasma corticosterone response to acute stress than slower chicks (LP, low performers). High-performing quail from a line selected for reduced rather than exaggerated (high-stress) adrenocortical stress responsiveness also show enhanced female reproductive performance when compared with LP-high-stress quail. Herein, time courses of male sexual development were evaluated in genetically unremarkable quail that were categorized at 2 d of age as HP or LP in the T-maze. Body weight, cloacal gland volume (CVOL), proportion of individuals that produced cloacal gland foam, intensity of foam production, and CVOL relative to BW (RCVOL) were determined weekly from 4 to 10 wk of age, and again at 22 wk, along with absolute and BW-adjusted testes weight. Although CVOL and RCVOL were initially similar in both T-maze groups, both variables were greater (P < 0.05) in HP than in LP quail between 6 and 10 wk of age. High-performing birds also showed a trend (P < 0.1) of greater cloacal gland foam than their LP counterparts from 5 to 7 wk. From 8 wk on, all birds were in foam production. Intensity of foam production results generally mimicked those found for CVOL and RCVOL. Body weights were higher (P < 0.05) in HP than LP quail from 5 to 7 wk. No T-maze group differences were found in any of the variables at 22 wk of age. The results suggest that rapid negotiation of the T-maze is associated with accelerated growth and puberty in male quail, although the enhanced reproductive development of HP males does not remain extant in aged adults.
Lábaque
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Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto de Ciencia y Tecnología de los Alimentos, Edificio de Investigaciones Biológicas y Tecnológicas, Físicas y Naturales, Universidad Nacional de Córdoba, 5016, Argentina.
Satterlee
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Guzman
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DA
Marin
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RH
D000375:Aging; D000818:Animals; D002988:Cloaca / Q000033:anatomy & histology / Q000502:physiology*; D003370:Coturnix / Q000502:physiology*; D008297:Male; D018782:Maze Learning; D012149:Restraint, Physical; D012641:Selection, Genetic; D012741:Sexual Maturation