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.

SUMMARYStudying biochemical changes in the blood and liver of geese during cramming showed significant increases in the liver enzymes: malic dehydrogenase (MDH), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and malic enzyme (ME), and a decrease in alkaline phosphatase (ALP). No significant changes were seen in the activity of isocitric dehydrogenase (ICDH), and glucose 6 phosphate dehydrogenase (G6PDH). There were significant increases in serum ME, ICDH, LDH, MDH, AST, acid phosphatase (ACP), sorbitol dehydrogenase (SDH), and total lipids and decreases in serum ALP, albumin and the haemocrit. No significant changes were seen in the activity of cholinesterase, glucose, total proteins, globulins and inorganic phosphorus. There were good correlations between liver size and the change of some of the biochemical parameters studied, which may serve as markers for the presence and degree of liver fattening. There were differences between families of gray and white geese and concentrations and activities of the blood constituents paralleled the degree of liver fattening. The possibility of using these parameters as genetic markers is discussed. No correlations were found between the liver and serum biochemical parameters. The effect of transporting the geese from the farm to the slaughter house on the levels of the blood constituents is described.

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Summary:A qualitative field test for determining the blood level of the enzyme γ-glutamyltransferase is described for the evaluation of colostral ingestion. The method for enzyme determination is based on dry chemistry technology, and a simple 37 °C incubator and colour chart for estimating the activity. There were good correlations between results obtained with the field tests and those obtained with the Reflotron® and the wet chemistry conventional methods. Following colostral intake by the calf, blood γ-glutamyltransferase increased more than 100 fold. There were good correlations between γ-glutamyltransferase and total globulins in the serum on days 2 and 3 after colostrum intake. Lower but significant correlations were seen between the enzyme and serum total proteins. Good correlation was also seen between the serum enzyme activity and the albumin to globulin ratio. Electrophoretic separation of calf serum showed a significant increase of γ-globulins after colostral ingestion. The implications and importance of field test are discussed.

SUMMARYThe effects of long term hyperthermia on enzyme levels in the chicken heart and breast muscles, brain, kidney, liver and lung, in relation to sex and degree of feathering, were studied. The enzymes studied were alanine and aspartate aminotransferases, alkaline phosphatase, creatine kinase, lactic dehydrogenase and gammaglutamyltransferase. Double heterozygote frizzled naked neck and normally feathered male and female broilers were exposed to 24°C (control group) and 32°C (experimental group), for 5 weeks, starting at the age of 3 weeks. The birds were killed, the tested organ removed, homogenized and cell-free supernatant was obtained by centrifugation. Enzyme activities were measured with an autoanalyser and specific activities were calculated.Prolonged heat stress resulted in changes of enzyme activities in all the tissues studied.No significant differences were seen in the cellular enzyme levels from the various organs between male and female birds unexposed to heat stress. Following heat stress, however, greater changes in enzyme levels were seen in the brain, heart muscle and kidney of males compared to females. No significant differences were seen in the cellular enzymes studied in the tissues between the normal and frizzled naked neck chicken. Following prolonged heat stress, there were some differences in the degree of response between the frizzled naked neck and control groups. These differences did not show a consistent or clear pattern indicative of the degree of stress in each of the groups.