Exposing broiler eggs to green, red and white light during incubation.

Previous work has shown that exposing broiler eggs to white light during incubation can improve hatchability and post-hatch animal welfare. It was hypothesized that due to how different wavelengths of light can affect avian physiology differently, and how pigmented eggshells filter light that different monochromatic wavelengths would have differential effects on hatchability and post-hatch animal welfare indicators. To determine, we incubated chicken eggs (n=6912) under either no light (dark), green light, red light or white light; the light level was 250 lux. White and red light were observed to increase hatch of fertile (P0.05). Fear response of during isolation and tonic immobility was reduced (P0.05) from dark incubated broilers. All light incubated broilers had lower (P<0.05) plasma corticosterone and higher (P<0.05) plasma serotonin concentrations than dark incubated broilers. These results indicate that white light and red light that is a component of it are possibly the key spectrum to improving hatchability and lower fear and stress susceptibility, whereas green light is not as effective. Incubating broiler eggs under these spectrums could be used to improve hatchery efficiency and post-hatch animal welfare at the same time.

Effect of high-dose total body irradiation on ACTH, corticosterone, and catecholamines in the rat.

Total body irradiation (TBI) or partial body irradiation is a distinct risk of accidental, wartime, or terrorist events. Total body irradiation is also used as conditioning therapy before hematopoietic stem cell transplantation. This therapy can result in injury to multiple tissues and might result in death as a result of multiorgan failure. The hypothalamic-pituitary-adrenal (HPA) axis could play a causative role in those injuries, in addition to being activated under conditions of stress. In a rat model of TBI, we have established that radiation nephropathy is a significant lethal complication, which is caused by hypertension and uremia. The current study assessed HPA axis function in rats undergoing TBI. Using a head-shielded model of TBI, we found an enhanced response to corticotropin-releasing hormone (CRH) in vitro in pituitaries from irradiated compared with nonirradiated rats at both 8 and 70 days after 10-Gy single fraction TBI. At 70, but not 8 days, plasma adrenocorticotrophic hormone (ACTH) and corticosterone levels were increased significantly in irradiated compared with nonirradiated rats. Plasma aldosterone was not affected by TBI at either time point, whereas plasma renin activity was decreased in irradiated rats at 8 days. Basal and stimulated adrenal steroid synthesis in vitro was not affected by TBI. In addition, plasma epinephrine was decreased at 70 days after TBI. The hypothalamic expression of CRH messenger RNA (mRNA) and hippocampal expression of glucocorticoid receptor mRNA were unchanged by irradiation. We conclude that the hypertension of radiation nephropathy is not aldosterone or catecholamine-dependent but that there is an abscopal activation of the HPA axis after 10 Gy TBI. This activation was attributable at least partially to enhanced pituitary ACTH production.

Effect of constant light on prolactin and corticosterone rhythms evaluated using a noninvasive urine sampling protocol in the rat.

Circadian prolactin and corticosterone rhythms are usually investigated in the rat by analysis of plasma hormone profiles. In order to develop a nonstressful methodology for long-term studies, we validated prolactin and corticosterone radioimmunoassays in rat urine samples. Among the criteria of validation, prolactin was identified in urine by Western blot whereas both prolactin and corticosterone levels were undetectable in the urine of hypophysectomized rats. The determination of prolactin and corticosterone levels on serial urine samples showed daily variations in male rats entrained by the light-dark cycle. The acrophases of the 24-hour prolactin and corticosterone profiles were located at 03:26 h and 23:32 h respectively, a delay of 3-4 hours compared with the values of the 24-hour plasma profiles reported in the literature. Corticosterone and prolactin rhythms were abolished or dramatically delayed after 3 weeks of constant illumination. As expected, constant light suppressed the rhythm of 6-sulfatoxymelatonin, the major hepatic metabolite of melatonin. The noninvasive and nonstressful methodology we developed could be of interest for studying the regulation of hormone rhythms and their mutual endocrine interactions in physiological conditions, especially their evolution in the aging process.

Winter day lengths enhance T lymphocyte phenotypes, inhibit cytokine responses, and attenuate behavioral symptoms of infection in laboratory rats.

Annual variations in day length (photoperiod) trigger changes in the immune and reproductive system of seasonally-breeding animals. The purpose of this study was to determine whether photoperiodic changes in immunity depend on concurrent photoperiodic responses in the reproductive system, or whether immunological responses to photoperiod occur independent of reproductive responses. Here we report photoperiodic changes in enumerative, functional, and behavioral aspects of the immune system, and in immunomodulatory glucocorticoid secretion, in reproductively non-photoperiodic Wistar rats. T-cell numbers (CD3+, CD8+, CD8+CD25+, CD4+CD25+) were higher in the blood of rats housed in short as opposed to long-day lengths for 10 weeks. Following a simulated bacterial infection (Escherichia coli LPS; 125 microg/kg) the severity of several acute-phase sickness behaviors (anorexia, cachexia, neophobia, and social withdrawal) were attenuated in short days. LPS-stimulated IL-1beta and IL-6 production were comparable between photoperiods, but plasma TNFalpha was higher in long-day relative to short-day rats. In addition, corticosterone concentrations were higher in short-day relative to long-day rats. The data are consistent with the hypothesis that photoperiodic regulation of the immune system can occur entirely independently of photoperiodic regulation of the reproductive system. In the absence of concurrent reproductive responses, short days increase the numbers of leukocytes capable of immunosurveillance and inhibition of inflammatory responses, increase proinflammatory cytokine production, increase immunomodulatory glucocorticoid secretion, and ultimately attenuate behavioral responses to infection. Seasonal changes in the host immune system, endocrine system, and behavior may contribute to the seasonal variability in disease outcomes, even in reproductively non-photoperiodic mammals.

Immune and stress responses in C57BL/6 and C3H/HeN mouse strains following photoperiod manipulation.

OBJECTIVES: The purpose of this study was to determine whether two different strains of mice, that are reproductively unresponsive to photoperiod, adjust immune function in response to photoperiod. SETTING AND DESIGN: Adult male C3H/HeN (C3H) and C57BL/6 (C57) mice were each placed into either a long (LD 16:8) or short (LD 8:16) photoperiod for 10 weeks (n = 15/ group). METHODS: Blood was collected for flow cytometry and radioimmunoassay analysis of leukocyte numbers and corticosterone concentrations, respectively. In addition, all mice were sensitized to, and challenged with the antigen, 2,4-dinitro-1-fluorobenzene. Pinnae measurements were obtained for 7 days following challenge to determine the magnitude of the inflammatory response. RESULTS: Photoperiod did not affect leukocyte cell numbers in either C3H or C57 mice. C3H mice displayed higher neutrophil numbers than C57 mice (p< 0.0001), whereas C57 mice displayed higher lymphocyte numbers than C3H mice (p< 0.01). C3H mice housed in LD 16:8 had higher corticosterone concentrations than those housed in LD 8:16 (p< 0.005) and C57 mice housed in either photoperiod (p< 0.05). Photoperiod did not affect the inflammatory response, though C57 mice displayed an overall higher magnitude of response than C3H mice (p<0.05). MAIN FINDINGS: Our results suggest that photoperiod does not alter immune function in C3H and C57 mice. Strain differences in immune function, however, were observed. CONCLUSIONS: Immune function is unresponsive to photoperiod in these laboratory mice, possibly indicating; a link between immune and reproductive responsiveness to photoperiod, the decreased predictive value of this annual cue to domesticated animals, or both.

Effect of heavy ions on neuro-endocrine regulations.

During American and Russian short and long-term space flights neuroimmune dysregulations have been observed in man and rats for up to three months after the return. During Extra-Vehicular Activity, radiation exposure risk is greater to elicit short and/or long-term deleterious effects on the functional capacity of the neuroimmune system. In order to assess the effects of high LET events on neuroimmune networks, our preliminary ground-based study was to investigate brain inflammatory responses in mouse after low dose radiation exposure with high LET particles (12C, 95MeV/u, 42 mGy). Plasma corticosterone levels were rapidly (6 hours) increased by two-fold, then decreased 24 hours post-irradiation. At 3 days plasma corticosterone and ACTH concentrations were also two- to three-fold increased. Plasma ACTH levels were still elevated up to seven days to two months. Furthermore immune functions are under current assessment. The results of this study should allow a greater understanding of the effects of high LET particles on neuroimmune system.

[Corticosterone and testosterone in the blood of adult rats: the effects of low doses and the times of the action of ionizing radiation during intrauterine development]. / Kortikosteron i testosteron v krovi vzroslykh krys: éffekty nizkikh doz i sroka deistviia ioniziruiushchei radiatsii v period vnutriutrobnogo razvitiia.

Corticosterone levels in the blood and adrenal weights in adult rat males were increased after low-dose gamma irradiation during the last third of their intrauterine development; an increase of the dose decreased them. Decrease in testosterone levels and testis weights were dose-dependent. External and internal irradiation of females on the 11-14 days of pregnancy inhibited adrenals and increased testosterone levels and seminal vesicles weights in offspring. The changes of hormonal balance in adult animals depend on dose and period of ionizing irradiation during intrauterine development.

[The functional dynamics of the system of immunity in rats during adaptation to single and fractionated exposures to low doses of external gamma irradiation]. / Dinamika sostoianiia sistemy immuniteta krys v protsesse adaptatsii k odnokratnomu i fraktsionirovannomu vozdeistviiu malykh doz vneshnego gamma-oblucheniia.

The content of serum corticosterone so as immunological and nonspecific reactivity in rats exposed to single or fractionated gamma-radiation (0.35 Gy) were studied during 1 month. It has been revealed that corticosterone level, dynamics of absolute amount of leucocytes, lymphocytes, Rc-receptor-bearing cells in blood, relative content of FcR(+)-cells in bone marrow, spleen and peripheral lymph nodes of irradiated animals depend on the scheme of irradiation. Single irradiation didn't significantly influence natural and antibody-dependent killer cells activity and basal chemiluminescence level of polymorphonuclear cells, while the fractionated irradiation in equal dose induced considerable fluctuations of these parameters. The direction and intensity of the disturbances depend on the time after irradiation.

[The individual characteristics of the nociceptive sensitivity of Wistar rats correlated with the content of steroid hormones in the blood plasma]. / Individual'nye osobennosti notsitseptivnoi chuvstvitel'nosti krys linii Vistar v korreliatsii s soderzhaniem steroidnykh gormonov v plazme krovi.

In male rats of Wistar strain individual nociceptive sensitivity properties were studied in correlation with steroid hormones level in the plasma. Seven groups of experimental animals were observed remarkable for dynamics of nociceptive sensitivity. Repeatedly applied test painful stimuli caused reliable changes of corticosterone and testosterone level in the plasma. Individual differences were found of the level of steroid hormones in the plasma in rats from different groups.

[Reaction of the endocrine system and peripheral blood of rats to a single and chronic exposure to pulsed low-frequency electromagnetic field]. / Reaktsiia éndokrinnoi sistemy i perifericheskoi krovi krys na odnokratnoe i khronicheskoe vozdeistviia impul'snogo élektro- magnitnogo polia nizkoi chastoty.

Wistar male rats underwent a single exposure for 20 min, 1 and 2.5 hour to a pulsed electromagnetic field of 20 mT or a single exposure for 2.5 hour and a chronic exposure for 6 hours a day during 30 days to a pulsed electromagnetic field of 0.1 mT, the pulse time and an interval between pulses being 10(-2) sec. As a result, the experimental animals showed changes in the activity of the adrenals, thyroid and sex glands as well as eosinopenia and lymphopenia. The concentration of thyroid hormones and lymphocytes remained lowered during 2 months after a single exposure to 20 mT. In some cases the exposure modified the physiological responses of rats to an acute stress-5-hour immobilization.

[Corticosterone receptor binding by various brain structures in extreme body states]. / Retseptornoe sviazyvanie kortikosterona razlichnymi strukturami golovnogo mozga pri ékstremal'nykh sostoianiiakh organizma.

Studies on receptor binding of 3H-corticosterone in different brain structures of mature Wistar rats after a single x-irradiation at a dose of 12.9 mCoul/kg, short-term vertical vibration, glucocorticoid application, and surgical adrenalectomy showed a high sensitivity of all studied structures to the body level of glucocorticoids. Any of these influences caused redistribution of receptor binding of 3H-corticosterone in all brain structures, with a marked effect in the parietal cortex and mediobasal hypothalamus, which characterized the central mechanisms of regulation of the pituitary-adrenal system under extreme influences.

Plasma corticosterone in hemorrhaged Japanese quail after microwave irradiation in ovo.

1. Sexually immature male and female Japanese quail were divided within each sex into three treatment groups: hemorrhaged by jugular puncture; immobilized for 2 min, but not hemorrhaged (shams); and neither immobilized nor hemorrhaged (controls). 2. Hemorrhage resulted in increased plasma corticosterone levels in both sexes. Corticosterone levels in shams were higher than in controls. 3. In another experiment, Japanese quail eggs were irradiated during incubation with 2.45 GHz CW microwave radiation. Nonirradiated eggs were incubated under identical conditions without irradiation. After hatching, juvenile males and females were hemorrhaged. 4. After hemorrhage, irradiated males had higher plasma corticosterone levels than nonirradiated males. No effect of irradiation on females was found. 5. The results of these two experiments indicate that male quail respond to blood loss with increased adrenocortical activity and that this response is modified in male quail after irradiation with microwaves during embryogeny.

Metabolic changes after non-lethal x-irradiation of rats. I. Carbohydrates, hormones.

Male rats of the Wistar strain were fasted overnight prior to exposure to single total-body X-ray dose of 2.39 Gy (250 R). Irradiated and sham-irradiated rats were pair-fed for 5 days, in the next period they were fed ad libitum. The levels of corticosterone and immunoreactive insulin in serum, glucose in blood, glycogen in liver, heart and skeletal muscle were determined 1 and 6 h, 1, 2, 3, 7, 14, 28, and 38 days after irradiation and sham-irradiation. Irradiation of rats resulted, at one hour, in a decrease and, at two days, in an icrease in level of blood glucose. A marked increase in liver glycogen persisted from 6 h to 21 days after irradiation. The level of glycogen in the skeletal muscle was reduced at 6 h and increased on days 3 and 14. Heart muscle glycogen declined within the first 24 h and rose at 14 days after exposure. The kinetics of changes in the heart and skeletal muscle glycogen following non-lethal irradiation was similar and indicated an overlap of changes produced by fasting with those brought about by irradiation, particularly during the first week. Corticosterone in serum was markedly increased in rats at 24 and 72 h after irradiation compared to pair-fed controls. The serum insulin concentration did not change after irradiation, except for a single increase on day 21. Irradiation with non-lethal doses produced changes in the parameters of the carbohydrate metabolism studied, except for serum insulin, which reflected the changes in the nutrition regimen upon pair-feeding rather than the effect of ionizing irradiation.

Effects of hypophysectomy and dexamethasone on rat adrenal response to microwaves.

Circulating corticosterone levels were measured to compare the adrenocortical response to acute microwave exposure of normal, hypophysectomized, or sham-hypophysectomized rats. Plasma corticosterone levels in acutely hypophysectomized rats exposed to 60 mW/cm2 for 60 min were below control levels, indicating that the microwave-induced corticosterone response observed in normal, intact rats is dependent on ACTH secretion by the pituitary. In other groups of rats pretreated with dexamethasone before being exposed to microwaves for 60 min, the corticosterone response to a 50-mW/cm2 exposure was completely suppressed by doses equal to or greater than 3.2 micrograms dexamethasone/100 g body weight. However, the corticosterone response to a 70-mW/cm2 exposure was only partially suppressed by prior administration of 3.2 or 5.6 micrograms dexamethasone/100 g BW. The evidence obtained in these experiments, in conjunction with the results of other experiments previously reported, is consistent with the hypothesis that the stimulation of the adrenal axis in the microwave-exposed rat is a systemic, integrative process due to a general hyperthermia.