Meeting Abstract

P1.87  Wednesday, Jan. 4  Effects of yolk testosterone levels and post-hatch food availability on wound healing in male domestic chickens (Gallus gallus) SWEENEY, K.M.*; GARREHY, C.A.; FISHER, K.A.; BENOWITZ-FREDERICKS, Z.M.; Bucknell University; Bucknell University; Bucknell University; Bucknell University kms060@bucknell.edu

Avian phenotypes are affected by both physiological maternal effects and post-hatch environmental conditions. We investigated the interactions between yolk testosterone levels, a maternal effect, and post-hatch food availability in young male domestic chickens (Gallus gallus). We hypothesize that maternal testosterone is more likely to promote fitness when environmental conditions, specifically food availability, are favorable. However when post-hatch environmental conditions are suboptimal, chicks exposed to elevated yolk testosterone may suffer reduced fitness compared to those from low yolk testosterone eggs. We investigated immune function as a phenotypic measure important to fitness. To assess the effects of both yolk testosterone levels and post-hatch food availability on immune function, we used a wound healing assay, which was previously validated in non-avian systems. We injected unincubated chicken eggs with 5 ng of testosterone dissolved in 50 μL of sesame oil (“T”) or with 5 μL of sesame oil (“C”). On day 7 post-hatch, 30 T males and 20 C males were evenly distributed into diet cohorts. “Ad libitum” chicks had unlimited access to undiluted Poultry Starter Mix while “restricted” chicks had unlimited access to the same food diluted with 30% oat hull filler. Wound healing measures the effectiveness of an integrated innate immune response to a cutaneous wound by measuring the healing rate of a small biopsy. A 5 mm diameter biopsy punch was taken from the wing web of each animal. Standardized photographs of the biopsy areas were taken at days 20, 23, and 26, and the area of the biopsy site that remained open was measured digitally. Preliminary data suggest that wound healing is slower in chicks exposed to elevated yolk testosterone.