Biomaterial Database

Effects of body temperature on ventilation, blood gases and acid-base balance in exercising fowl. 1984

M Gleeson, and J H Brackenbury

In order to determine the influence of hyperthermia on respiratory, blood gas and acid-base changes in exercising birds, we exercised domestic fowl on a treadmill at ambient temperatures of 5, 20, 30 and 35 degrees C for 10 min at graded running speeds up to 4.3 km.h-1. Ventilation and gas exchange were measured continuously and arterial blood gases, pH and the concentration of lactic acid in arterial blood were measured in samples taken during the last minute of each run. During exercise at 5 degrees C rectal temperature did not change significantly from rest (isothermic condition) and there was no sign of thermal influence on respiratory pattern, such as was observed at higher ambient temperatures. At any given running speed, increased ambient temperature caused increased ventilation by an increase in respiratory frequency (f) together with a decrease in tidal volume (VT). Under isothermic conditions, at low running speeds, birds maintained an isocapnic hyperpnoea: arterial PCO2, PO2 and pH and oxygen extraction were unchanged. However at higher speeds (ca. greater than 2.5 km.h-1) some hyperventilation occurred with subsequent falls in arterial PCO2 and oxygen extraction. Arterial pH also fell significantly (P less than 0.01). During hyperthermic exercise, oxygen extraction, arterial PCO2 and bicarbonate concentration all fell significantly (P less than 0.01) and progressively with increasing work load, and birds hyperventilated at all running speeds. This produced a significant arterial hypocapnia and alkalosis at the lower speeds (P less than 0.05) but this was replaced by a hypocapnic metabolic acidosis at the higher running speeds. Blood lactate concentration rose steeply at speeds above ca. 2.5 km.h-1 but arterial pH fell by only 0.1 units or less partly as a result of buffering by blood bicarbonate. It is concluded that both hyperthermia and lactacidosis are causes of hyperventilation and arterial hypocapnia during heavy running exercise in birds. However, ventilatory adjustments similar to those observed in resting hyperthermic birds, viz. increased f and reduced VT prevent severe arterial hypocapnia from occurring in hyperthermic exercising birds.

UI	MeSH Term	Description	Entries
D007773	Lactates	Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D010313	Partial Pressure	The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Partial Pressures,Pressure, Partial,Pressures, Partial
D011659	Pulmonary Gas Exchange	The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.	Exchange, Pulmonary Gas,Gas Exchange, Pulmonary
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D001831	Body Temperature	The measure of the level of heat of a human or animal.	Organ Temperature,Body Temperatures,Organ Temperatures,Temperature, Body,Temperature, Organ,Temperatures, Body,Temperatures, Organ
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D005082	Physical Exertion	Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.	Physical Effort,Effort, Physical,Efforts, Physical,Exertion, Physical,Exertions, Physical,Physical Efforts,Physical Exertions
D005260	Female		Females