Characterization of serum enzyme activities and electrolyte levels in broiler chickens after death from sudden death syndrome.

Serum activities of lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), and creatine phosphokinase (CPK), and serum levels of Na+ and K+ were measured in blood samples from healthy broilers and from broilers suffering from Sudden Death Syndrome (SDS) within 30 min after death. The LDH activity was higher in 4- to 9-wk-old SDS birds than in healthy birds (P < 0.05). The GOT activity was higher in SDS birds irrespective of age (P < 0.05). The CPK activity of SDS birds was not significantly different from that of healthy birds. The K+ level was about twofold higher in SDS birds of 4 to 6 and 7 to 9 wk of age than in healthy birds of the same age, whereas the Na+ level did not differ from that of healthy birds. The LDH, GOT, and CPK activities and Na+ level were unchanged for the post-mortem period of 30 min, but the K+ level increased. These results suggest that an elevations in serum LDH and GOT activities occur in association with SDS, and may be used as a characteristic sign of birds that are dying of SDS.