Effect of somatotropin on survival and diameter of bovine preantral follicles

Abstract

The aim of this study was to evaluate the effect of Recombinant bovine somatotropin (rbST) on survival and diameter of bovine preantral ovarian follicles (PAOF) cultured in vitro. Ovaries were collected from adult cows and fragments of ovarian cortex were immediately fixed (non-cultured control) or cultured in vitro in α-MEM+ alone or containing 10, 50, 100 or 1,000ng/mL rbST. The fragments were processed for Classical Histology and Transmission Electron Microscopy. After one and seven days of culture, the percentage of normal follicles in the non-cultured control was superior (P< 0.05) to the follicles cultured in α-MEM+ alone or with different rbST concentrations. The oocyte and follicular mean diameter did not increase during the culture for one and seven days, both in media containing rbST and in the medium without this hormone. The only medium in which there was no reduction in follicular diameter with the time of culture was the medium without rbST. Ultrastructural damage in PAOF cultured in vitro was found. It is concluded that the use of rbST at different concentrations in in situ culture of bovine preantral follicles has no beneficial effects on survival and growth of bovine PAOF.

Recombinant bovine somatotropin in the synchronization of ovulation in crossbred dairy cows (Bos taurus indicus × Bos taurus taurus)

“…Tcontrol=Control treatment, TrbST=Treatment with rbST, Means lacking a common superscript letter in a row differ by Tukey's test (p<0.05). 2 Tcycling=Treatment with cycling cows, and Tanestrous=Treatment with anestrous cows, 2,3 Means lacking a common superscript letter in the same line differ by Tukey's test (p<0.05). SEM=Standard error of mean…”

“…It has been shown that rbST stimulates the production of endogenous growth hormone and insulin-like growth factor I (IGF-I), which are crucial for reproduction. In addition, the presence of rbST receptors in the uterus and ovaries has previously been observed [3].…”