The Relationship between Heat Stress, Survivability and Blood Composition of the Domestic Chicken

Abstract

In order to better understand the metabolic changes leading to death which take place in the chicken during acute heat stress, the blood composition was determined in surviving and non-surviving chickens. The following blood analytes were determined: glucose, uric acid, serum total proteins, inorganic phosphate, total and ionized calcium, sodium, potassium, triiodothyronine, thyroxine. The haematocrit, erythrocyte creatine kinase (total and the isoenzymes) and haemoglobin fractions were also measured. Blood was taken from the wing vein before and after heat stress.Eight-week-old "Anak 2000" broilers were kept in a climate chamber at 24 °C/40% relative humidity during a 14-hour day, and at 20 °C/40% relative humidity during a 10-hour night. The birds were subjected to heat stress by exposing them to 40 °C/30% relative humidity for 3 hours.Significant differences between heat-stressed surviving and non-surviving chickens were seen in the blood levels of glucose, uric acid, total and ionized calcium, potassium, triiodothyronine, erythrocyte creatine kinase (total and isoenzymes). Differences were also seen in the levels and ratio of the 2 haemoglobin fractions.The significance of these changes, and their potential use as markers for heat resistance is discussed.

Injury and mortality in broilers during handling and transport to slaughter

“…The ability of the bird to lose heat from evaporative cooling is dependent on a gradient in temperature and/or moisture between the bird and the surrounding environment (Kettlewell 1989 If a bird becomes hyperthermic and the body temperature approaches a lethal body temperature of about 46 o C, the depth of respiration increases, but the rate decreases (Kettlewell 1989). Death from hyperthermia is likely to be preceded by a period of respiratory distress and open-mouthed panting together with metabolic changes (circulatory and electrolyte imbalances) (Bogin et al 1996;Borges et al 2004). Hyperventilation results in loss of carbon dioxide from blood and tissues, blood pH, rises causing respiratory alkalosis.…”

“…Hyperventilation results in loss of carbon dioxide from blood and tissues, blood pH, rises causing respiratory alkalosis. In birds that die from hyperthermia, there is an increase in serum concentrations of uric acid, potassium and sodium (Bogin et al 1996;Borges et al 2004). The survival time for broilers before they collapse from heat prostration and die depends on the temperature rise, duration of exposure and the thermal regulatory ability of individual birds, e.g.…”

Effect of Short Term Heat Stress on Antibody Production and Blood Constituents of Baladi and Leghorn Chickens

“…The effect of heat stress on blood chemical constituents of chickens was reported by previous workers (Bogin et al, 1996), but little is known about the changes in blood constituents during the establishment of a n immune response to SRBC in these birds. The present study indicated that immunization did not significantly influence the studied blood constituents with the exception of Zn, whose concentration was markedly decreased in the immunized chickens (Table 1).…”

Sex and genotype dependence on the effects of long‐term high environmental temperatures on cellular enzyme activities from chicken organs

“…These changes affected glucose, uric acid, calcium, inorganic phosphorus, thyroxin and electrolytes (Pech-Waffenschmidt etal, 1995). There were differences in some of the blood constituents between the surviving and non-surviving birds, suggesting possible mechanisms associated with survivability to heat stress (Bogin et al, 1996).…”