Effects of short-term in vitro heat stress on bovine preantral follicles

CARDONE, D.A.; BRUNA, F.A.; SANHUEZA, M.A.; CÁCERES, A.R.R.; LACONI, M.R.

LIVESTOCK SCIENCE

ELSEVIER SCIENCE BV

Año: 2022

1871-1413

Heat stress occurs when heat dissipation mechanisms are overwhelmed by externaland internal heat production. Ovarian reserve is an important contributor toreproductive success in cattle. The effects of heat stress on antral follicle developmenthave been well studied, but the consequences on preantral follicles are still largelyunknown. This study aimed to investigate and characterize the effects of a short invitro heat stress exposure on bovine preantral follicles, with a special focus onprimordial follicles. Bovine ovarian cortex fragments (3 x 3 x 1 mm) were isolated andincubated at different temperatures for 2 hours. The incubation methodology wasvalidated using a non-incubated group. Incubation groups were exposed tophysiological temperature (38.5°C) or heat stress (41°C). Data on follicle count,diameter of the primordial follicles, number of granulosa cells, and markers for follicleproliferation and degeneration were recorded. Heat stress caused a significantdecrease in the number of primordial follicles (p