D.G. Harvey

A Review of Factors Affecting Blood Biochemistry in the Pig

SUMMARY Lack of information on the clinical biochemistry of the conventional pig compared with many other species is due, among other factors, to the present economic policy of culling or isolating unthrifty animals without preliminary biochemical investigation, and the animals intractability which makes blood and urine sampling difficult. This paper discusses the effects of some normal environmental factors such as age, sex, breed and particularly diet, as well as some disease conditions, on the levels of some organic serum components such as protein, urea, cholesterol, certain enzymes including alkaline phosphatase, glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, glutamate and sorbitol dehydrogenases, arginase, carbamoyl transferase and lactate dehydrogenase, several of which are in current use in the diagnosis of liver disease and muscle dystrophy in other species. Bromsulphthalein clearance and urine analysis for common abnormalities are also discussed. It is concluded, on somewhat slender evidence, and taking into account the effects of age, diet, etc., that liver function can best be assessed routinely by S-GOT, OCT, possibly LDH and to a lesser degree by S-GPT, and kidney function by analysis of urine for abnormalities, and blood or serum for urea. Limited work indicates the possible value of BSP clearance for liver function, but intractability of the species renders this less useful as a routine test. Estimations of serum proteins and cholesterol do not appear to offer much useful information in assessing liver and kidney function. It is concluded that further basic studies must be carried out, more specifically on alkaline phosphatase, glutamate and sorbitol dehydrogenases in order to make it possible to recommend a larger battery of routine tests for liver function, and that estimations of serum urea, urinary protein and phenolsuiphonphthalein clearances should be investigated in connection with kidney function.

The routine estimation of serum cholesterol with special reference to low concentrations.

SUMMARY Four methods of serum cholesterol estimation were compared in six species of animal, with particular reference to low concentrations such as are normally found in sheep. There were considerable variations between ‘direct’ and ‘extractive’ methods, the former yielding apparently higher cholesterol values than the latter. Some improvement can be made in the accuracy of the methods. Although an extraction method is essential for precise work, direct methods appear to be satisfactory for routine purposes, provided no claim is made that the levels obtained represent absolute levels of cholesterol.