Effect of temperature on embryogenesis of Trichuris ovis during in vitro cultivation

Abstract

One of the priority tasks of animal husbandry development is environmental protection from contamination of environmental objects with eggs, larvae of helminths, cysts, and oocysts of intestinal parasites, which are dangerous for animals and humans. For this purpose, it is relevant to determine the leading factors and ways of transmission of pathogens of parasitoses, the terms of their development, and survival under various abiotic influences in the conditions of certain climatic regions. The work aimed to determine the influence of the temperature factor on the embryonic development of nematodes of the species Trichuris ovis, parasitizing sheep. It was established that the embryogenesis of T. ovis varies from 27 to 36 days, depending on the temperature regime, where the development of eggs occurs in 6 stages. The duration of each stage of embryonic development of trichurises of this species also depends on temperature. The temperature at 25 °C was the most susceptible for developing T. ovis eggs in laboratory conditions, where 80.67 % of invasive larvae were formed on the 36th day. At this temperature, the zygote stage lasted up to 9 days, crushing and formation of blastomeres – up to 12 days, bean-like embryo – up to 18 days, tadpole-like embryo – up to 24 days, and larva formation – up to 30 days. The temperature of 20 °С was less susceptible to developing T. ovis eggs, where 77.0 % of invasive eggs were formed on the 33rd day of cultivation. At this temperature, the zygote stage lasted up to 9 days, crushing and formation of blastomeres – up to 15 days, bean-like embryo – up to 18 days, tadpole-like embryo – up to 24 days, and larva formation – up to 33 days. At a temperature of 30 °С, the term of embryogenesis of T. ovis turned out to be the shortest – 27 days, but at the same time, the smallest number of invasive eggs was formed – 71.0 %. At this temperature, the zygote stage lasted up to 6 days, crushing and formation of blastomeres – up to 12 days, bean-like embryo – up to 15 days, tadpole-like embryo – up to 21 days, and larva formation – up to 24 days. The obtained research results expand the existing scientific data and will also allow us to effectively plan the timing of measures for destroying pathogens of sheep trichurosis in the embryonic stages of development in the external environment.