The potential for using enzymatic assays to assess the health of turkeys

Enzymatic activity assays, used mainly to show biochemical transformations in humans and mammals, have recently found increasing application in birds. Enzyme activity in birds is affected by numerous factors, including age, sex, species, breed, nutrition, physiological state, and farming techniques. In large-scale poultry breeding, in a flock that may number over ten thousand birds, individual birds may be in different stages of development of a disease process, and may respond differently to stress factors present during rearing. There is also high individual variation among birds, so that results of enzyme activity analyses fall within fairly broad ranges. The aim of this paper is to review experiments on the activity of selected antioxidant, liver and cardiac enzyme profiles in turkey tissues. The results of many years of measurements of the activity of selected enzymes, presented in this study, may be considered physiologically normal for this group of birds. Analyses of the activity of these enzymes are important in determining whether oxidative stress reactions are induced in cells and which cells or organs have been damaged. During oxidative stress, which leads to cell damage or organ dysfunction (of the liver or heart), there is generally an increase in the activity of AST, ALT, ALP, LDH, GGT, SORD, MDH, AC, G6PC, G6PD, Cp, CK and HBDH, and a decrease in that of SOD, GPx, CAT, ACHE, BCHE, SDH, Ca2+ ATPase. On the basis of the literature reviewed it can be concluded that the use of feed components and supplements with antioxidant or immunostimulatory properties can mitigate oxidative stress, which is manifested as beneficial changes in the activity of these enzymes.