Observations on the Embryonic Development of Trichuris sylvilagi (Nematoda, Trichuridae) under Laboratory Conditions

In the present study, we observed in vitro the rate and stages of exogenous development of the nematode Trichuris sylvilagi Tiner, 1950 isolated from the European hare, Lepus europaeus. The viability of eggs and embryos at different temperatures was investigated. It was found that the most favorable temperature for embryonic development of the species was 30 °C, with the formation of 88.67 % of viable eggs with a motile larva in 20 days at laboratory conditions. With a decrease in temperature to 20 °C, the embryogenesis occurred in 32 days. The viability of eggs cultured at 20 °C decreased: 68.0 % of eggs reached larval stage, and 32.0 % of eggs died. At 10 °C eggs did not develop to infective stage. On the 32nd day of cultivation at 10 °C, 27.33 % of eggs remained at the zygote stage, 52.0 % at the stage of blastomere cleavage and formation, and 20.67 % died. Embryogenesis was characterized by metric changes in egg parameters. At optimal temperature, the growth and development of eggs was accompanied by an increase in the egg and plugs' width with a simultaneous decrease in their length, as well as with thinning of the shell