Supplemental Thyroid Hormones and Hatchability of Turkey Eggs

Christensen, V. L.

doi:10.3382/ps.0642202

Cited by 21 publications

(11 citation statements)

References 22 publications

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“…The observations of this study support previous hypotheses (Christensen and Biellier, 1982;Christensen, 1985) that aberrant metabolism of turkey embryos during pipping and hatching results in a high embryonic death rate late in the incubation period. Most embryonic mortality occurs during the paranatal period (24 to 25 days for turkey embryos) at both sea level (Cherms, 1981) and high altitude (Bagley, 1987).…”

Section: Hatchability Hatching Was Defined Bysupporting

confidence: 90%

Improved Hatchability of Turkey Eggs at High Altitudes Due to Added Oxygen and Increased Incubation Temperature

Christensen

Bagley

1988

Poultry Science

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Turkey egg hatchability at high altitudes was examined at two different oxygen tensions and two incubation temperatures. Incubating turkey eggs in a 149-torr oxygen environment at 37.7 C gave significantly better hatchability than a 109-torr oxygen environment at 37.5 C. Embryonic mortality data indicated that the higher incubation temperature in combination with increased oxygen tension decreased embryonic mortality during the 3rd and 4th wk of incubation and resulted in higher hatchability. The data suggest that hatchery managers at high altitudes should supplement with oxygen and incubate turkey eggs at higher temperatures than employed at lower altitudes.

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Section: Hatchability Hatching Was Defined Bysupporting

confidence: 90%

Improved Hatchability of Turkey Eggs at High Altitudes Due to Added Oxygen and Increased Incubation Temperature

Christensen

Bagley

1988

Poultry Science

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“…As PRL is thought to modulate a multiplicity of actions in vertebrates [2,40], changes in PRL mRNA, pituitary content, and plasma concentrations in PRL observed before and after hatching might have an effect on at least one if not all of the physiological parameters mentioned above. Thyroid hormones are involved and are important for the survival of the embryo during hatching [10,39]. Since PRL was reported to act on thyroid hormone metabolism in chicken embryo via specific receptors in the liver [11][12][13], and PRLR mRNA is present in the thyroid and the liver of adult turkey hens [41], the variations in PRL observed in our study about the time of hatching may therefore act on thyroid hormones by modulating their concentrations and/or activation.…”

Section: Discussionmentioning

confidence: 92%

“…A stimulatory role upon T-cell maturation [8] and possibly on thymus development [9] was reported in the chicken. In addition, thyroid hormones, which appear to be important for the survival of the embryo during hatching [10], can be influenced by PRL [11][12][13]. Furthermore, PRL also seems to be involved in the control of osmoregulation by stimulating the reabsorption of NaCl from the fetal urine by the metanephric kidneys [14,15].…”

Section: Introductionmentioning

confidence: 99%

Quantification of Prolactin Messenger Ribonucleic Acid, Pituitary Content and Plasma Levels of Prolactin, and Detection of Immunoreactive Isoforms of Prolactin in Pituitaries from Turkey Embryos During Ontogeny1

Bédécarrats¹,

Guemene²,

Morvan³

et al. 1999

Biology of Reproduction

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The content of prolactin mRNA as well as total prolactin content and type of isoforms of prolactin were measured in single pituitary glands from turkey embryos and poults. Levels of mRNA and pituitary content of prolactin remained low until 5 days before hatching, while plasma concentrations remained low until 2 days before hatching. Levels of prolactin mRNA then increased until the day of hatch, stayed stable during the 3 first days of age, and significantly increased until 2 wk of age. Similar changes were observed in pituitary content and plasma levels of prolactin. Two immunoreactive bands of apparent molecular masses of 24 and 27 kDa, corresponding to the nonglycosylated and glycosylated form of prolactin, respectively, were visualized on Western blots. In pituitary glands from embryos at 22 days of incubation, 31.5% of the protein was glycosylated, whereas in embryos at 27 days of incubation and poults at 1 and 7 days of age, 48.6%, 48.0%, and 56. 0% of prolactin was glycosylated, respectively. The results indicate that the increases in the synthesis and the release of prolactin occur mainly around and after the time of hatching in the turkey embryo. Higher percentages of glycosylated isoforms were associated with increasing levels of total prolactin in the pituitary gland. Thus, the synthesis of prolactin and its post-translational modifications may be important factors involved in the physiologic changes occurring around the time of hatching.

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“…Early hatching is associated with increased plasma T 3 (review: Decuypere and Kühn, 1988). Small amounts of exogenous T 4 introduced into turkey eggs prior to incubation can improve hatchability (Christensen, 1985), and differences in 5 D II activity and plasma T 4 concentrations (substrate availability) leading to T 3 production appear to play a role in different hatching times in weight-selected lines of chickens .…”

Section: Hatchingmentioning

confidence: 99%

The Hypothalamic-Pituitary-Thyroid (HPT) Axis in Birds and Its Role in Bird Development and Reproduction

McNabb

2007

Critical Reviews in Toxicology

189

163

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This article reviews thyroid function and its hypothalamic-pituitary-thyroid (HPT) axis control in birds with emphasis on the similarities and differences in thyroid function compared to mammals and other vertebrate classes. Thyroid hormones are important in metabolism and the thermogenesis required for homeothermy in birds, as in mammals, the other homeothermic class of vertebrates. Thyroid hormones play important roles in development and growth in birds, as is the case for all vertebrate classes. The developmental effects of thyroid hormones in birds are presented in the context of differences in precocial and altricial patterns of development and growth with emphasis on oviparous development. The sections on thyroid hormone actions include discussion of effects on the development of a number of tissue types as well as on seasonal organismal processes and interactions of the thyroid axis with reproduction. The current picture of how environmental chemicals may disrupt avian thyroid function is relatively limited and is presented in the context of the assessment endpoints that have been used to date. These endpoints are categorized as thyroid and HPT axis endpoints versus target organ endpoints. The final section discusses two recommended assay protocols, the avian two-generation toxicity assay and the avian one-generation assay, and whether these protocols can evaluate thyroid disruption in birds.

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Supplemental Thyroid Hormones and Hatchability of Turkey Eggs

Cited by 21 publications

References 22 publications

Improved Hatchability of Turkey Eggs at High Altitudes Due to Added Oxygen and Increased Incubation Temperature

Improved Hatchability of Turkey Eggs at High Altitudes Due to Added Oxygen and Increased Incubation Temperature

Quantification of Prolactin Messenger Ribonucleic Acid, Pituitary Content and Plasma Levels of Prolactin, and Detection of Immunoreactive Isoforms of Prolactin in Pituitaries from Turkey Embryos During Ontogeny1

The Hypothalamic-Pituitary-Thyroid (HPT) Axis in Birds and Its Role in Bird Development and Reproduction

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