Incubation

About: Incubation is a research topic. Over the lifetime, 5748 publications have been published within this topic receiving 126541 citations.

Evaluation of DNA methylation and mRNA expression of heat shock proteins in thermal manipulated chicken

Abstract: Thermal manipulation during embryogenesis has been demonstrated to enhance the thermotolerance capacity of broilers through epigenetic modifications. Heat shock proteins (HSPs) are induced in response to stress for guarding cells against damage. The present study investigates the effect of thermal conditioning during embryogenesis and thermal challenge at 42 days of age on HSP gene and protein expression, DNA methylation and in vitro luciferase assay in brain tissue of Naked Neck (NN) and Punjab Broiler-2 (PB-2) chicken. On the 15th day of incubation, fertile eggs from two breeds, NN and PB-2, were randomly divided in to two groups: control (C)-eggs were incubated under standard incubation conditions, and thermal conditioning (TC)-eggs were exposed to higher incubation temperature (40.5°C) for 3 h on the 15th, 16th, and 17th days of incubation. The chicks obtained from each group were further subdivided and reared under different environmental conditions from the 15th to the 42nd day as normal [N; 25 ± 1 °C, 70% relative humidity (RH)] and heat exposed (HE; 35 ± 1 °C, 50% RH) resulting in four treatment groups (CN, CHE, TCN, and TCHE). The results revealed that HSP promoter activity was stronger in CHE, which had lesser methylation and higher gene expression. The activity of promoter region was lesser in TCHE birds that were thermally manipulated at the embryonic stage, thus reflecting their stress-free condition. This was confirmed by the lower level of mRNA expression of all the HSP genes. In conclusion, thermal conditioning during embryogenesis has a positive impact and improves chicken thermotolerance capacity in postnatal life.

Impairment of Isoproterenol, H2 Histamine, and Prostaglandin E1 Response of Human Granulocytes after Incubation in Vitro with Live Influenza Vaccines1, 2

Abstract: The release of the lysosomal enzyme beta-glucuronidase from granulocytes follows incubation in vitro with complement-activated zymosan particles. Release of beta-glucuronidase is inhibited by isopr...

Reversal of cell surface abnormalities of T lymphocytes in hodgkin's disease after in vitro incubation in fetal sera.

Abstract: The capacity of peripheral blood lymphocytes from patients with untreated Hodgkin9s disease to form E rosettes with sheep erythrocytes and to respond in vitro to PHA stimulation were found to be profoundly impaired. In 49% of the patients, the percentage of E rosette-forming cells (E-RFC) was more than two standard deviations below the mean for normal donors. Overnight incubation of the peripheral blood lymphocytes from these patients in culture media containing 20% fetal calf serum was followed by restoration of the percentage of E-RFC up to normal levels. Similar results have been observed after incubation in fetal human serum, but not in adult human AB serum or adult bovine serum. Incubation of peripheral blood lymphocytes from untreated patients in 20% fetal calf serum also resulted in a remarkable restoration of their capacity to respond normally to PHA. Possible mechanisms involved in these reversible cell surface and in vitro lymphocyte function abnormalities in Hodgkin9s disease are discussed.

Clutch size and the costs of incubation in the house wren

Abstract: Trade-offs in the allocation of finite resources among different stages of a breeding attempt as well as between different reproductive events should shape the evolution of life-history traits. To investigate the effects of incubation effort on within-brood and between-brood trade-offs in house wrens (Troglodytes aedon), we manipulated the clutch size that females incubated. We isolated effects of incubation by reversing the manipulation at hatching to allow all parents to provision their natural brood sizes. Females that incubated enlarged clutches had longer incubation periods than control females, both early and late in the season, suggesting that the experimental treatment increased incubation effort. Contrary to predictions, however, increased incubation effort did not adversely affect the allocation of effort to nestling provisioning. Rather, in the early season, but not in the late season, females that incubated enlarged clutches appeared to allocate more effort to nestling provisioning, producing heavier and larger fledglings than control females. Although females with enlarged early-season clutches consequently lost more mass than control females, this was likely an adaptive response to reduce wing loading in anticipation of high provisioning demands. There were no treatment-related differences in fledgling mass or size, or in female mass loss, in the late season. Thus, elevated incubation demands negatively affected a fitness-related trait (duration of incubation) that may constrain clutch size but not the allocation of resources to subsequent stages of the same breeding event or to subsequent breeding events. We suggest that environmental conditions may mediate clutch-size effects on trade-offs in allocation of resources between incubation and nestling provisioning. Key words: clutch size, house wren, incubation, life history, trade-offs, Troglodytes aedon. [Behav Ecol]

Critical windows in embryonic development: Shifting incubation temperatures alter heart rate and oxygen consumption of Lake Whitefish (Coregonus clupeaformis) embryos and hatchlings

Abstract: Critical windows are periods of developmental susceptibility when the phenotype of an embryonic, juvenile or adult animal may be vulnerable to environmental fluctuations. Temperature has pervasive effects on poikilotherm physiology, and embryos are especially vulnerable to temperature shifts. To identify critical windows, we incubated whitefish embryos at control temperatures of 2 °C, 5 °C, or 8 °C, and shifted treatments among temperatures at the end of gastrulation or organogenesis. Heart rate (f H ) and oxygen consumption ( V ˙ O 2 ) were measured across embryonic development, and V ˙ O 2 was measured in 1-day old hatchlings. Thermal shifts, up or down, from initial incubation temperatures caused persistent changes in f H and V ˙ O 2 compared to control embryos measured at the same temperature (2 °C, 5 °C, or 8 °C). Most prominently, when embryos were measured at organogenesis, shifting incubation temperature after gastrulation significantly lowered V ˙ O 2 or f H . Incubation at 2 °C or 5 °C through gastrulation significantly lowered V ˙ O 2 (42% decrease) and f H (20% decrease) at 8 °C, incubation at 2 °C significantly lowered V ˙ O 2 (40% decrease) and f H (30% decrease) at 5 °C, and incubation at 5 °C and 8 °C significantly lowered V ˙ O 2 at 2 °C (27% decrease). Through the latter half of development, V ˙ O 2 and f H in embryos were not different from control values for thermally shifted treatments. However, in hatchlings measured at 2 °C, V ˙ O 2 was higher in groups incubated at 5 °C or 8 °C through organogenesis, compared to 2 °C controls (43 or 65% increase, respectively). Collectively, these data suggest that embryonic development through organogenesis represents a critical window of embryonic and hatchling phenotypic plasticity. This study presents an experimental design that identified thermally sensitive periods for fish embryos.