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Full-Text Articles in Physiology
The Effects Of Food Supply On Reproductive Hormones And Timing Of Reproduction In An Income-Breeding Seabird, Shannon Whelan, Scott A. Hatch, Z. Morgan Benowitz-Fredericks, Charline Parenteau, Olivier Chastel, Kyle Elliott
The Effects Of Food Supply On Reproductive Hormones And Timing Of Reproduction In An Income-Breeding Seabird, Shannon Whelan, Scott A. Hatch, Z. Morgan Benowitz-Fredericks, Charline Parenteau, Olivier Chastel, Kyle Elliott
Faculty Journal Articles
Current food supply is a major driver of timing of breeding in income-breeding animals, likely because increased net energy balance directly increases reproductive hormones and advances breeding. In capital breeders, increased net energy balance increases energy reserves, which eventually leads to improved reproductive readiness and earlier breeding. To test the hypothesis that phenology of income-breeding birds is independent of energy reserves, we conducted an experiment on food-supplemented (“fed”) and control female black-legged kittiwakes (Rissa tridactyla). We temporarily increased energy costs (via weight handicap) in a 2 × 2 design (fed/unfed; handicapped/unhandicapped) during the pre-laying period and observed movement …
Prenatal Aromatase Inhibition Alters Postnatal Immunity In Domestic Chickens (Gallus Gallus), Jeff W. Simkins, Abby E. Joseph, Frances Bonier, Z. Morgan Benowitz-Fredericks
Prenatal Aromatase Inhibition Alters Postnatal Immunity In Domestic Chickens (Gallus Gallus), Jeff W. Simkins, Abby E. Joseph, Frances Bonier, Z. Morgan Benowitz-Fredericks
Faculty Journal Articles
In birds, exposure to exogenous testosterone during embryonic development can suppress measures of immune function; however, it is unclear whether these effects are due to direct or indirect action via aromatization. Estradiol (E2) is synthesized from testosterone by the enzyme aromatase, and this conversion is a necessary step in many signaling pathways that are ostensibly testosterone-dependent. Many lines of evidence in mammals indicate that E2 can affect immune function. We tested the hypothesis that some of the immunomodulatory effects observed in response to in ovo testosterone exposure in birds are mediated by conversion to E2 by aromatase, by using fadrozole …
Effects Of Prenatal Environment Are Revealed By Post-Natal Challenges: Embryonic Hormone Exposure, Adrenocortical Function And Food In Seabird Chicks, Z. Morgan Benowitz-Fredericks, Jannik Schultner, Alexander S. Kitaysky
Effects Of Prenatal Environment Are Revealed By Post-Natal Challenges: Embryonic Hormone Exposure, Adrenocortical Function And Food In Seabird Chicks, Z. Morgan Benowitz-Fredericks, Jannik Schultner, Alexander S. Kitaysky
Faculty Journal Articles
The interaction between prenatal environments and postnatal environments is an important source of phenotypic variability. We examined the ability of prenatal steroid exposure and postnatal energy restriction to explain adrenocortical function and fledging age in captive seabird chicks. We proposed and tested two hypotheses: (1) the strength of prenatal effects is attenuated by challenging postnatal environments (postnatal override) and (2) the strength of prenatal effects increases with the severity of postnatal challenges (postnatal reveal). We reared common murre (Uria aalge) chicks and measured prenatal exposure to corticosterone (CORT) and testosterone (T) from allantoic waste. Adrenocortical function was assessed after 10 …