RECOVERY OF HEPATIC-FUNCTION AND LATENT MORTALITIES IN SHEEP EXPOSED TO THE BLUE-GREEN-ALGA MICROCYSTIS-AERUGINOSA

Seventeen sheep died, and many others showed signs of hepatogenous pho tosensitivity after being exposed to Microcystis aeruginosa at Lake Mo koan, Victoria, Australia, Two groups of sheep were observed, and thei r hepatic recovery was monitored by means of serum biochemical tests d uring the subsequent six months. During the first three weeks, their s erum gamma-glutamyl transferase activity and bilirubin concentration d eclined rapidly to normal levels, and the signs of hepatogenous photos ensitivity disappeared, Serum bile acid concentrations were above norm al for almost three months. Thirty-four per cent of the sheep died dur ing the observation period, and the serum biochemical tests provided n o clear indication of the cause of these delayed mortalities, This stu dy suggests that sublethal exposure to microcystins may cause prolonge d morbidity and delayed mortality.