Clinical chemical constituents in relation to liver amyloidosis in serum-producing horses.

This research monitored key biological markers in the blood of 27 horses used for serum production over a five-year period. It sought to establish links between these markers and the prevalence of liver amyloidosis -a disease involving protein deposits in the liver- in horses that were regularly immunized with certain bacteria. A key finding was that increased activity of gamma-glutamyl transferase (GGT) , a liver enzyme, may be an indicator of advanced liver amyloidosis.

Study Methodology

• The research was conducted over five years on 27 horses that were used for producing hyperimmune serum. These horses were regular subjects of immunization with live cultures of bacteria Escherichia coli or Pasteurella multocida.
• The amount of immunization varied from 2 weeks to 10 years per horse.
• The study examined several blood chemistry components, including the activities of gamma-glutamyl transferase (GGT), alkaline phosphatase (AP), aspartate aminotransferase (AST), as well as concentrations of total bilirubin and total bile acids.

Key Findings

• In many horses, the activity of GGT increased within the first 6 to 7 years after immunization began.
• The high values of GGT seemed to correlate with the presence of advanced liver amyloidosis, as evidenced by histopathological examination after the horses were slaughtered.
• Additionally, the alkaline phosphatase activity raised but was moderate compared to GGT. In some extreme cases, the GGT increased over 10-fold while alkaline phosphatase levels reached less than double the upper reference limit.
• While the values for AST and bilirubin concentrations remained largely unaffected, the concentration of total bile acids rose after 6 to 7 years of immunization.

Conclusions

• The study concluded from these findings that measuring the serum activity of GGT could serve as a practical routine test for evaluating the status of liver amyloidosis in horses used for serum production.