TY - JOUR AU - Fernandes da Silva, Talita AU - Paulino da Costa, Eduardo AU - Lourenço da Costa, Sanely AU - Domingos Guimarães, José PY - 2018/04/10 Y2 - 2024/03/29 TI - Effect of somatotropin and thyroxine on the in vitro development of bovine preantral follicles JF - Ciência Animal Brasileira / Brazilian Animal Science JA - Ciênc. anim. bras. VL - 19 IS - SE - MEDICINA VETERINÁRIA DO - 10.1590/cab19145994 UR - https://revistas.ufg.br/vet/article/view/e-45994 SP - 1-9 AB - <p><span style="font-family: 'Times New Roman', serif; font-size: 16px; text-align: justify;">The aim of the study was to evaluate the effect of recombinant bovine somatotropin (rbST) and thyroxine (T4) on survival and growth of bovine preantral ovarian follicles (PAOF) cultured&nbsp;</span><em style="font-family: 'Times New Roman', serif; font-size: 16px; text-align: justify;">in vitro</em><span style="font-family: 'Times New Roman', serif; font-size: 16px; text-align: justify;">. Ovarian fragments were collected in local abattoirs and immediately fixed for classical histology and transmission electron microscopy (non-cultured control). The other fragments were then cultured in situ for seven days in minimum essential medium alone (MEM+ - cultured control) or in the presence of 1,000 ng/mL rbST and 20 ng/mL T4, isolated or associated. After seven days, there was a reduction (P&lt;0.05) in the percentage of normal follicles in MEM+ alone or with T4. In oocyte diameter, there was a reduction in MEM+ alone. There was no influence (P&gt;0.01) of the medium used on the follicular diameter of the PAOF cultured for seven days. Ultrastructural analysis showed cell damage. In conclusion, the presence of rbST maintains the rate of morphologically normal follicles during the culture for seven days (observed by optical microscopy), but it does not exert beneficial effects on its ultrastructural integrity and oocyte and follicular growth.&nbsp;</span><br style="font-family: 'Times New Roman', serif; font-size: 16px; text-align: justify;"><br></p> ER -