[Effects of different toxic compounds (Pb, Cu, formol, NH4) on the carp: histologic changes in excretory and hematopoietic organs].

: Here is a comparative study of the impairments observed on the histological structure of the excretory and hematopoietic organs of carps after acute intoxication (by formol and ammonia) and chronic intoxication (by copper sulfate and lead nitrate). Although all these toxic substances induce the same type of impairments, their degree of seriousness vary. The most affected organs are the gills which present with congestive reactions and partial destruction of respiratory lamellae, and the spleen whose red pulp is usually destroyed. On the other hand, the proliferation of a parasitic fungus was observed on all intoxicated carps. This was understood as a weakening of their body's natural defenses.