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Some humoral factors of nonspecific resistance have been determined in carp yearlings in 28 days after intraperitoneal administration of fungi culture filtrate (I), conidia (II), micellar extract (III) of the fungus Aspergillus fumigatus Fres., physiological solution (control). The toxicogenic and immunogenic effect of the fungus has been shown in I and II variants of the experiment respectively. The injection of fungus micella did not have any influence on the studied factors. The account of specific and quantitative composition of zooparasites in experiments and under control has been carried out; no truly differences have been revealed.

Three species of micromycetes (Aspergillus clavatus Desm., Cladosporium herbarum (Pers) Lk., Penicillium canescens Sopp.) isolated from the cultivated salmon spawn have been studied for their toxigenic properties and pathogenicity for warm-blooded animals. LD50 are determined for mice perorally administered mycelium suspension of the first two species; the third of the studied species proved to be nontoxicogenic. The possible pathogenic action of mycotoxins on fish spawn in aquarium is discussed.

The fungi Aspergillus fumigatus Fres., and Fusarium sporotrichiella Bilai were studied for their effect on certain biochemical indices of two-year carp and spawn of grass carp under laboratory conditions. The intraperitoneal introduction of A. fumigatus in a dose of 5 and 20 min conidia per individual to two-year carp decreased significantly the protein level in blood serum, the decrease being more considerable with the introduction of the smaller dose of fungal conidia. Joint incubation of the grass carp spawn and F. sporotrichiella induced changes in the protein level, amylolytic and phosphate (acid phosphatase) activity in spawn. In that case the time of the fungus action on grass carp spawn was a decisive factor. Activity of certain hydrolytic enzymes in mycelium and conidia of A. fumigatus and F. sporotrichiella was determined. The amylolytic activity was not revealed in the checked samples. The proteolytic activity was established in all samples of fungi and culture liquid, the highest level being observed in mycelia and conidia of A. fumigatus. The alkaline and acid phosphatase activity was found in F. sporotrichiella: the acid phosphatase activity was higher in mycelium, the acid phosphatase one in the fungus conidia. The problem on the A. fumigatus ability to produce extracellular enzymes is under discussion.