Effect of somatotropin on survival and diameter of bovine preantral follicles

T.F Silva,E.P Costa,J.D Guimarães,V.L.D Queiroz-Castro,S.L Costa

doi:10.1590/1678-4162-10602

Abstract

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.

Highlights

The growing development of Brazilian livestock has led to an incessant search for the production and reproduction of species with economic interest
This peptide acts through the synthesis of Insulin-like Growth Factor 1 (IGF-1) and IGF Binding Proteins (IGFBP) (Gong et al, 1997)
There was no difference (P< 0.05) in the percentage of normal follicles among cultured treatments and when compared to the different culture times. These results demonstrate that Recombinant bovine somatotropin (rbST), at the concentrations used, was not able to maintain follicular survival

Summary

Introduction

The growing development of Brazilian livestock has led to an incessant search for the production and reproduction of species with economic interest. For this purpose, the development and application of reproduction biotechniques, such as the Manipulation of Ovocytes Enclosed in Preantral Ovarian Follicles (MOEPF), is fundamental (Araújo et al, 2014). Among the hormones that have been the target of research in the area of animal reproduction is Somatotropin (ST), known as Growth Hormone (GH) It is a peptide composed of 192 amino acids, synthesized by cells located in the adenohypophysis, which participates in several physiological and metabolic processes of cattle. This peptide acts through the synthesis of Insulin-like Growth Factor 1 (IGF-1) and IGF Binding Proteins (IGFBP) (Gong et al, 1997)

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Conclusion