Effects of the pesticides atrazine and lindane and of manganese ions on cellular immunity of carp, <i>Cyprinus carpio</i>

Abstract

Pesticides and metals in the aquatic environment can peturb the fish immune system and, consequently, increase their susceptibility to pathogenic agents. Lindane, an insecticide, was tested for its effects on skin graft rejection after daily administration in the food for 1 month (1000 mg lindane kg −1 food). No difference was observed from the control for the first set of graft rejection times (8 days) or for the second set of graft rejection times (5 days), even if the lymphoid organs were highly contaminated with lindane. Atrazine, lindane and manganese were tested for their effect on in vitro phagocytosis of Yersinia ruckeri and zymosan (yeast extract) by pronephric and splenic macrophages. Neither pesticide had any effect on macrophage phagocytosis at concentrations up to their limit of solubility in water. Manganese ions, in the range 6.25–50 ppm, had a strong enhancing effect on phagocytosis of Y. ruckeri , as did zymosan, but only at a concentration of less than 6.25 ppm.