Date of Award:

5-1980

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

William A. Brindley

Committee

William A. Brindley

Committee

Ronald W. Goede

Committee

Joseph C. Street

Committee

Ross O. Bulkley

Committee

Paul B. Carter

Committee

Eldon Gardner

Abstract

DDT can cause hematological and immunological alterations in mammals and birds. Interference with normal hematological and immunological defense systems has been strongly linked to increased incidences of disease and tumors. Fish exposed to pesticides have been noted to be more susceptible to disease. This study examined DDT effects on goldfish hematological and immunological parameters.

Adult goldfish were kept in 250 liter aquaria at 25 ± 1° C. Fish were dosed intraperitoneally with p,p'-DDT in corn oil. Doses ranged from 0 to 500 mg/kg for acute (96 hour) hematology studies to 0 to 50 mg/kg for sub-acute hematology and immunology studies.

The 96 hour LD50's increased from 213 to 480 to 579 mg/kg for groups of fish weighing approximately 20, 50 or 110 grams respectively.

In acute hematology tests, effects of DDT dose upon seven hematological parameters were determined. In general, numbers of erythrocytes and leukocytes (and associated parameters) were decreased with increasing DDT dose. Hematological alterations were moderated as fish size increased.

In the sub-acute tests, effects of repeated sub-lethal doses of DDT upon the hematological parameters and immunological responses of medium-sized fish were investigated over a one to two month span. In general, some of the hematological parameters stabilized after increased duration of DDT exposure. Nevertheless, numbers of leukocytes (especially percent lymphocytes) often remained reduced after DDT treatment.

DDT treatment generally resulted in suppression of primary and secondary immune responses. Numbers of Jerne-plaque forming cells in anterior kidney and spleen were often reduced by DDT pretreatments, as were the serum titers of hemolysin, hemagglutinin and anti-bovine serum albumin. DDT also suppressed the normal rejection of scale-graft transplants (allografts). These results indicated that DDT interfered with the normal humoral and cell-mediated immune responses of this species and may help explain how pesticide exposure could result in increased susceptibility of fish to infectious diseases.

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