Hypercapnic thresholds for embryonic acid-base metabolic compensation and hematological regulation during CO2 challenges in layer and broiler chicken strains.
Time specific acid-base metabolic compensation and responses of hematological respiratory variables were measured in day 15 layer (Hyline) and broiler (Cornish Rock) chicken embryos during acute hypercapnic challenges (3, 6, 10 and 20% CO2). Control acid-base status and hematology differed between two strains. Broiler embryos were relatively respiratory acidotic and had higher hematocrit (Hct) and hemoglobin concentration. The partial metabolic compensation for respiratory acidosis produced by ≤ 10% CO2 exposures occurred in proportion to CO2 concentrations in both strains, but metabolic compensation for 20% CO2 respiratory acidosis was depressed at 2, 6 and 24h, particularly in broiler embryos. Exposure to ≤ 10% CO2 induced the same hematological responses across CO2 concentrations; i.e., Hct and mean corpuscular volume (MCV) increased while RBC concentration remained unchanged. In response to 20% CO2 exposure, Hct and MCV increased dramatically in both stains. Consequently, altered acid-base and hematology responses to 20% CO2 exposure compared to ≤ 10% CO2 suggest that the hypercapnic threshold to compensation for acidosis and regulation of hematology is >10% CO2.
Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, 1155 Union Circle #302220, Denton, TX 76203, USA. Electronic address: burggren@unt.edu.
Warren W
WW
Burggren
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada.
Casey A
CA
Mueller
Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, 1155 Union Circle #302220, Denton, TX 76203, USA.
Hiroshi
H
Tazawa
D000136:Acid-Base Equilibrium / Q000187:drug effects* / Q000502:physiology; D000142:Acidosis, Respiratory / Q000503:physiopathology*; D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide / Q000494:pharmacology*; D002642:Chick Embryo; D002645:Chickens; D047108:Embryonic Development; D004909:Erythrocyte Indices; D006400:Hematocrit; D006935:Hypercapnia / Q000097:blood* / Q000473:pathology*; D019344:Lactic Acid / Q000378:metabolism; D017711:Nonlinear Dynamics; D009994:Osmolar Concentration; D013045:Species Specificity
D002245:Carbon Dioxide; D019344:Lactic Acid
Acid–base balance; Chicken embryo; Hematological respiratory variables; Hypercapnic threshold; Metabolic compensation; Respiratory acidosis