SHORT-TERM FASTING DOES NOT AGGRAVATE IMMUNOSUPPRESSION IN HARBOR SEALS (PHOCA-VITULINA) WITH HIGH BODY BURDENS OF ORGANOCHLORINES

Two groups of 11 harbour seals (Phoca vitulina) with different body bu rdens of organochlorines were subjected to an experimental 15-day fast ing period, during which they lost an average 16.5% of their body weig hts. Blood levels of the most persistent organochlorines showed an app roximate twofold increase, while levels of aryl hydrocarbon receptor-b inding organochlorines remained largely unaffected. Few differences in immunological parameters were observed between the two dietary groups . Numbers of circulating lymphocytes dropped to about 65% of the initi al values and NK cell activity showed a slight increase in both groups . Mitogen- and antigen-induced lymphoproliferative responses of the Ba ltic group of seals remained within normal ranges. These results sugge st that relatively short-term fasting periods do not present an additi onal immunotoxicological risk to seals with high body burdens of organ ochlorines.