Acid-base and hematological regulation in chicken embryos during internal progressive hypercapnic hypoxia

• Published in: Respiratory physiology & neurobiology 2023-02, Vol.308, p.103996-103996, Article 103996
• Main Authors: Burggren, Warren W., Andrewartha, Sarah J., Mueller, Casey A., Dubansky, Benjamin, Tazawa, Hiroshi
• Format: Article
• Language: English
• Subjects: Acid-Base Equilibrium - physiology; Acid-base regulation; Acidosis; Acidosis, Respiratory; Alkalosis; Animals; Chick Embryo; Chicken embryos; Chickens; Glycolysis; Hematocrit; Hematological variables; Hematology; Hypercapnia - metabolism; Hypoxia; Internal hypercapnic hypoxia; Water submersion
• ISSN: 1569-9048; 1878-1519
• DOI: 10.1016/j.resp.2022.103996

Development of the capacity to mitigate potential disturbances to blood physiology in bird embryos is incompletely understood. We investigated regulation of acid-base and hematology in day 15 chicken embryos exposed to graded intrinsic hypercapnic hypoxia created by varying degrees of water submersion. Metabolic acidosis with additional respiratory or metabolic acidosis occurred at 2 h according to magnitude of submersion. Acid-base disturbance was partially compensated by metabolic alkalosis at 6 h, but compensatory metabolic alkalosis was absent at 24 h. Following submersion with only air cell exposed to air, both hypercapnic respiratory acidosis and metabolic acidosis occurred within 10 min. Subsequently, both forms of acidosis created lethal levels of [HCO3-] at ∼120 min. Blood hematology showed small but significant effects associated with induced acid-base disturbance. Increased Hct occurring during partial egg submersion lasting 24 h was attributed to an increase in MCV. By day 15 of development chicken embryos are able to partially compensate for and withstand all but severe induced internal hypoxic hypercapnia. [Display omitted] •Graded levels of internal hypoxia and hypercapnia were induced in Day 15 chicken embryos using water submergence.•Embryos withstand all but severe induced internal hypoxic hypercapnia, indicating presence of acid-base regulation abilities.•Hypoxic hypercapnia had little effect on blood hematology (e.g. hematocrit, red blood cell and hemoglobin concentrations).