EFFECT OF TIME AND TEMPERATURE ON THE STORAGE STABILITY OF HEPATOBILIARY ENZYME ACTIVITIES IN CATTLE SERUM

The present research was conducted to choose an ideal storage condition for cattle sera samples meant for the assay of hepatobiliary enzymes viz., Alanine aminotransferases(ALT), Aspartate aminotransferases (AST), Alkaline phosphatase (ALP) and Gamma glutamyltransferases (GGT). The study was performed in adult healthy female crossbred cattle, during the period of April to October 2008.  Stabilities of enzymes in serum stored at room temperature (22 to 27 ºC), 4 ºC and -20 ºC were compared with the enzyme activities of fresh sera samples (day 0) on day 1, 2, 5, 8, 11 and 14.   Alanine aminotransferase was found to be sufficiently stable up to the study period of 14 days at 4 ºC, whereas it was unstable at room temperature and -20 ºC.  Aspartate aminotransferase was stable both at 4 ºC and -20 ºC up to14 days whereas at room temperature stable only up to 2 days. Alkaline phosphatase showed great variation upon storage as compared to other hepatobiliary enzymes and it is suggested that its estimation should be performed in fresh serum samples to get an accurate result. Cattle serum showed a lesser stability for GGT activity at -20 ºC as compared to 4 ºC where the observed stability period was 8 days and 11 days, respectively and at room temperature the enzyme was stable only for one day.  From these results it is therefore advisable to consider stability of each serum hepatobiliary enzymes for different animals separately before preserving sera samples to get more valid and reliable result.