Learn how to say Vivisectionists correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word vivisect:
(used only by opponents of the practice) perform vivisection on (an animal):
people are vivisecting animals and experimenting with germ warfare
science has been directed to the task of reducing, dividing, and vivisecting nature to manageable proportions
mid 19th century: back-formation from vivisection