Metabolic and Hematological Responses to Endotoxin‐Induced Inflammation in Chicks Experiencing Embryonic 2,3,7,8‐Tetrachlorodibenzodioxin Exposure

Abstract

Dioxin exposure during bird embryonic development disrupts immunity as well as mechanisms involved in energy metabolism, potentially affecting negatively acute-phase responses to pathogens. Thus, we hypothesized that embryonic exposure to 2,3,7,8-tetrachlorodibenzodioxin (TCDD) changes the metabolism and blood physiology of domestic chicks, affecting their physiological competence for responding to immune challenges. To test this hypothesis, we injected doses of 0, 1.5, and 3 ng TCDD/egg (based on survival experiments) on embryonic day 4 and then measured O 2 consumption and CO 2 production for metabolic rate, ventilation, and body temperature (T B) in 5-d-old chicks. Then, chicks were injected with lipopolysaccharide (LPS, endotoxin) or saline prior to repeating the physiological measurements. A second chick group exposed to identical TCDD and LPS treatments had blood partial pressure of oxygen, partial pressure of carbon dioxide, pH, bicarbonate concentration, lactate concentration, osmolality, hemoglobin concentration, red blood cell concentration, and hematocrit, as well as T B , analyzed at 1 and 5 h after LPS injection. Metabolism in chicks embryonically exposed to 1.5 and 3 ng TCDD/egg was up to 37% higher, whereas body mass of chicks exposed to 3 ng TCDD/egg was approximately 6% lower. Chicks embryonically exposed to 3 ng TCDD/egg challenged with LPS showed a relative persistent hypometabolism accompanied by elimination of the normal hematological and osmotic responses to LPS. We conclude that embryonic exposure to TCDD affects posthatching metabolism as well as impairs metabolic, hematological, and osmotic responses to LPS.

Dietary Exposure to Low Levels of Crude Oil Affects Physiological and Morphological Phenotype in Adults and Their Eggs and Hatchlings of the King Quail (Coturnix chinensis)

“…None of the blood chemistry or hematological variables measured in the offspring population varied significantly between experimental groups (Table 1). With exception of PO 2 and PCO 2 values that were associated with Tb of the hatchling, none of the variables were associated with the covariates for any of the hematological variables (the random effect of week of collection was not statistically significant, P > 0.05), with the exception of Osm (P < 0.002), Noteworthy is the fact that the values obtained in this study for the king quail fall within the ranges previously reported for hatchlings of the bobwhite quail (Colinus virginianus), the common quail (Coturnix coturnix), and the chicken (Gallus gallus; Burggren and Elmonoufy, 2017;Flores-Santin et al, 2018;Amaral-Silva et al, 2020). Similarly, none of the organ masses significantly differed between hatchlings from the Control, Low or High oil-exposed parental groups (Table 2) and, for none of the organ masses when the random effect of week of collection was included, with the exception of gut mass (P < 0.002).…”

“…Measurements of oxygen consumption (VO 2 ) and carbon dioxide production (VCO 2 ) of all adult quail were recorded at the end of the acclimation period, before any dietary exposure, and on weeks 1, 2, 3 5, and 7 after the start of the exposure. VO 2 andVCO 2 were measured by flow-through respirometry as previously reported (Amaral-Silva et al, 2020;Sirsat and Dzialowski, 2020). In brief, individual adult quail were placed inside 500 mL opaque respirometers that were maintained in an incubator to control temperature at 24 ± 0.5 • C. All individuals were allowed to acclimate to the respirometer for at least 30 min before measurements, during which time a flow of humidified air was maintained through the respirometer.…”

“…Breathing frequency (f, breaths * min −1 ) was determined with the cycle measurements function of LabChart 7 based on the changes in the pressure waves of the recordings. Tidal volume (V T ) was calculated as previously reported (Drorbaug and Fenn, 1955;Amaral-Silva et al, 2020;Sirsat and Dzialowski, 2020). Volume calibration of the system was performed by comparison with changes in pressure produced by injection of 250 µl volumes of air into the chambers using a Hamilton glass syringe (Hamilton, Reno, United States; Szdzuy and Mortola, 2007).…”

Regulated hypothermia in response to endotoxin in birds

“…analogous features that emerged independently during evolution) (Legendre & Davesne, 2020). Nevertheless, we and others have shown that a drop in body temperature (T b ) after endotoxin exposure can also occur in Galliformes, Columbiformes and Passeriformes (Pittman et al 1976;Nomoto, 2003;Owen-Ashley et al 2006;Burness et al 2010;King & Swanson, 2013;Sköld-Chiriac et al 2015;Dantonio et al 2016;Cornelius et al 2017;Ruhs et al 2019;Amaral-Silva et al 2020;Nord et al 2020), a response that appears to be accompanied by metabolic depression (Dantonio et al 2016;Amaral-Silva et al 2020). There is no evidence, however, that this endotoxin-induced T b decrease is actually part of a regulated hypothermic response of birds, instead of a systemic failure of thermogenesis.…”

“…The dose of LPS used was chosen based on a previously established dose-response curve (2, 10, 50 and 100 μg kg −1 ) of the effect of LPS on T b of 5-day-old chicks (Dantonio et al 2016). The highest dose of LPS induces an initial T b reduction followed by fever in ∼4 h (Dantonio et al 2016;Amaral-Silva et al 2020), whereas the low doses (2 and 10 μg kg −1 ) induce only a fever response ∼4 h after injection (Dantonio et al 2016). All experiments were conducted in the light phase between 07.00 h and 19.00 h. During the experiments, Ta was set to 30°C or 25°C, which is respectively considered neutral and cold for broiler chicks at this age (Shahir et al 2012;Dantonio et al 2016).…”