title: Incubation Temperature during Fetal Development Influences Morphophysiological Characteristics and Preferred Ambient Temperature of Chicken Hatchlings.
abstract: Skin and feather characteristics, which play a critical role in body temperature maintenance, can be affected by incubation circumstances, such as incubation temperature. However, no study to date has assessed the influence of incubation temperature during the fetal stage on morphometric characteristics and vascular development of the skin, feather characteristics, and their relationship to hormone levels and preferred temperature in later life in chickens. Broiler breeder eggs were exposed to low (36°C), control (37.5°C), or high (39°C) temperatures (treatments LT, CK, and HT, respectively) from day 13 of incubation onward, because it is known that the endocrine axes are already established at this time. During this period, eggshell temperature of HT eggs (38.8±0.33°C) was higher than of LT (37.4±0.08°C) and CK eggs (37.8 ±0.15°C). The difference between eggshell and incubator air temperature diminished with the increasing incubation temperature, and was approximately zero for HT. HT hatchlings had higher surface temperature on the head, neck, and back, and thinner and more vascularized skin than did CK and LT hatchlings. No differences were found among treatments for body weight, total feather weight, number and length of barbs, barbule length, and plasma T4 concentration. LT hatchlings showed lower plasma T3 and GH, as well as lower T3/T4 ratio and decreased vascularity in the neck, back, and thigh skin compared to CK hatchlings. On the other hand, HT hatchlings had decreased skin thickness and increased vascularity, and preferred a higher ambient temperature compared to CK and HT hatchlings. In addition, for all treatments, surface temperature on the head was higher than of the other body regions. We conclude that changes in skin thickness and vascularity, as well as changes in thyroid and growth hormone levels, are the result of embryonic strategies to cope with higher or lower than normal incubation temperatures. Additionally exposure to increased temperature during incubation is an environmental factor that can exert early-life influence on ambient temperature preference of broiler hatchlings in later life.
authors.affiliation: Department of Animal Morphology and Physiology, Sao Paulo State University, Access road Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, Sao Paulo, Brazil.
authors.forename: Viviane de Souza
authors.initials: Vde S
authors.lastname: Morita
authors.affiliation: Department of Animal Morphology and Physiology, Sao Paulo State University, Access road Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, Sao Paulo, Brazil.
authors.forename: Vitor Rosa
authors.initials: VR
authors.lastname: de Almeida
authors.affiliation: Department of Animal Morphology and Physiology, Sao Paulo State University, Access road Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, Sao Paulo, Brazil.
authors.forename: João Batista
authors.initials: JB
authors.lastname: Matos
authors.affiliation: Department of Animal Morphology and Physiology, Sao Paulo State University, Access road Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, Sao Paulo, Brazil.
authors.forename: Tamiris Iara
authors.initials: TI
authors.lastname: Vicentini
authors.affiliation: Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH, Wageningen, The Netherlands.
authors.forename: Henry
authors.initials: H
authors.lastname: van den Brand
authors.affiliation: Department of Animal Morphology and Physiology, Sao Paulo State University, Access road Professor Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, Sao Paulo, Brazil.
authors.forename: Isabel Cristina
authors.initials: IC
authors.lastname: Boleli
mesh_terms: D000818:Animals; D015415:Biomarkers; D002642:Chick Embryo; D002645:Chickens; D004531:Eggs; D005241:Feathers; D047109:Fetal Development; D006728:Hormones; D009024:Morphogenesis; D013696:Temperature; D013997:Time Factors
chemical_list: D015415:Biomarkers; D006728:Hormones