Quantification of multi-oocyte follicles in ovaries of bitches

A.P Zoppei,L Gruchouskei,A.C Martinez,A Pinto Neto,R Steffens,J Cattelam,C.K.G Trenkel

doi:10.1590/1678-4162-12385

Abstract

ABSTRACT The objective of this study was to quantify the number and frequency of monocyte (MnOF) and multi-oocyte (MtOF) follicles in ovaries of bitches subjected to ovary salpingohysterectomy (OSH). Right and left ovaries of 38 bitches were collected after OSH, prepared, and a histological analysis was carried out. The ovaries were subjected to surface and deep histological cuts; the follicles were classified, and the number of follicles and cumulus oophorus complexes (COC) per follicle were quantified for each histological cut. MnOF and MtOF were found in all ovaries, at different developmental stages; primary follicles were grouped in the ovarian cortex, and follicles at other follicular stages presented a random distribution. MtOF containing two, three, four, or more COC were found in the ovaries of bitches, with a decreasing frequency trend, according to the number of COC in the MtOF. The effect of the age, number of estrus, estrus interval, and number of progenies per delivery was not significant for the number and frequency of MtOF in the ovaries of the bitches, whereas the size, number of pregnancies, use and number of contraceptive applications had some effect on the number and frequency of MtOF in the ovaries of the bitches.

Highlights

Bitches are monoestrous, poliovulatory, nonseasonal animals, with a different reproductive cycle from other domestic animal species; they present high bloody progesterone concentrations in days preceding the ovulation, and oocytes ovulated at the immature diploid stage that finish their mitotic maturation in the uterine tubes, where they survive for several days (Rôlo, 2012).In addition, unlike other mammals, the oocyte production period by oogonia or primordial germ cells in bitches occur up to two months after birth since proliferation cells are found in the ovary cortical region
Folliculogenesis in bitches has high occurrence of polyovular follicles, with higher occurrences in young bitches, which decreasing during their senescence (Rôlo, 2012)
Bysted et al (2001) and Reynaud et al (2005) reported that multi-oocyte follicles can ovulate, releasing oocytes morphologically different from each other, because of unknown causes, which can be related to high pre-ovulatory follicle density in the ovarian cortex of young animals (Derussi and Lopes, 2009)

Summary

Introduction

Poliovulatory, nonseasonal animals, with a different reproductive cycle from other domestic animal species; they present high bloody progesterone concentrations in days preceding the ovulation, and oocytes ovulated at the immature diploid stage that finish their mitotic maturation in the uterine tubes, where they survive for several days (Rôlo, 2012).In addition, unlike other mammals, the oocyte production period by oogonia or primordial germ cells (oogenesis) in bitches occur up to two months after birth since proliferation cells are found in the ovary cortical region. The objective of this study was to quantify the number and frequency of monocytes (MnOF) and multi-oocyte (MtOF) follicles from ovaries of bitches subjected to ovary salpingohysterectomy (OSH). Ovaries of 38 bitches were subjected to OSH to collect data regarding age, weight, size, number of estrus, estrus interval, number of pregnancies, number of progenies per delivery, and use and number of applications of contraceptive.

Objectives

Results

Conclusion