The influence of the composition of culture medium on the survival and the number of ciliates maintained in vitro is presented in Fig. 1. The presented data showed that the survival of protozoa in the medium composed of the “caudatum” salt solution and lyophilized fungal zoospores (A) was shorter than 4 days. An enrichment of this medium with wheat gluten (B) prolonged the survival of ciliates up to 8 days. The supplementation of medium B with meadow hay (C) created the appropriate conditions for protozoa to survive for a period of 28 days at least. The effect of this enrichment
was not univocal. The concentration of protozoa decreased to 190 cells/ml (P < 0.01) during the first 8 days and followed with the continuous increase during the next 16 d. The positive effect of hay supplementation was observed only during the 8 last days of the cultivation period. The population density of E. maggii in these cultures found between 20 and 28 days of cultivation was 880e 1070 cells/ml, whereas the highest number of protozoa in control cultures did not exceed 810 cells/ml (P < 0.05). The protozoa in control cultures (D) also survived for the same period. i.e. 28 d. The similar relationship was found when E. maggii [23] or Diploplastron affine [4] were cultured in vitro in the medium containing commercial chitin instead of fungal zoospores. One of the possible explanations of this finding seems to be an increase in the energy content resulting from supplementation of control medium in commercial chitin or polysaccharides present in fungal zoospores. This suggestion is confirmed by enzymatic studies [23,24]. They revealed that E. maggii was possessing enzymes responsible for the breakdown of chitin and showed that N-acetylglucosoamine released from colloidal chitin could be an important source of energy for these ciliates.