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Ontogeny of breathing pattern and ventilatory chemosensitivity in altricial red‐winged blackbird ( Agelaius phoenixes ) nestlings
Author(s) -
Dzialowski Edward M,
Sirsat Tushar S.,
Sirsat Sarah K.G.,
Price Edwin
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1230.4
Subject(s) - altricial , ontogeny , hypercapnia , fledge , hatching , biology , hypoxia (environmental) , tidal volume , hypoxic ventilatory response , precocial , ventilation (architecture) , anatomy , respiratory system , endocrinology , medicine , oxygen , zoology , chemistry , mechanical engineering , organic chemistry , engineering
Altricial bird species, like the red‐winged blackbird, hatch at an immature level of functional maturity with very limited aerobic capacity. Over the next 9 days, red‐winged blackbirds develop increased metabolic capacity and fledge. Metabolic capacity is limited in the early neonate and the ontogeny of the ventilator chemosensitivity is unknown. Here we examined developmental changes in chemosensitivity of tidal volume (V T ), breathing frequency ( f ), minute ventilation (V E ), and whole‐animal oxygen consumption (Vo 2 ) from hatching to fledging in the red‐winged blackbird on days 3, 5, 7, and 9 days post hatching (dph) in response to hypercapnia (2 and 4% CO 2 ) and hypoxia (15 and 10% O 2 ). The barometric technique was used to estimate V T . Under control conditions, there was a developmental increase in V E with age that was due in part to increased V T with age. All ages exhibited a hypercapnic and hypoxic chemosensitivity. In response to hypercapnia, the 3 dph neonates increased V E by increasing both f and V T . From 5 dph on, the hypercapnic increase in V E was accounted for by increases in V T and not f . In response to hypoxia, all ages exhibited an increase in f at 10% O 2 , while V T decreased in older animals. This resulted in an increased V E at 3 dph with no change in V E at the later ages. Chemosensitivity in response to O 2 and CO 2 appear to mature early in the neonatal red‐winged blackbird, well before they are able to increase Vo 2 in response to cooling. Support or Funding Information National Science Foundation IOS‐1146758