Follicular flushing: a new alternative to improve oocyte Recovery by ovarian aspiration in cattle

Abstract

Follicular lavage (flushing) associated with follicular aspiration, or also called follicular flushing (FF) is a technique widely used for the oocyte recovery in women. In animals, it has already been used by transvaginal follicular aspiration in horses and aspiration of bovine ovaries from slaughterhouses. The recovery of the largest possible number of oocytes is the purpose of this method, as it corresponds to one or more washes of the punctured follicle immediately after follicular aspiration. This study aimed to compare the use of FF associated with follicular aspiration (FA) in bovine ovaries from slaughterhouses, in terms of oocyte recovery rates (ORT) and oocyte morphology. In FA, an 18G needle attached to a syringe was used. In the FF a manual system was elaborated in the INVITRO / CEBRAN laboratory, using parenteral infusion equipment, 3-way stopcock, needle, syringe, tube and vacuum pump. In this study, there was only an intra-follicular lavage. Oocytes were classified from A (COC) to F (Denudes), according to the number of cumulus cell layers, degree of compaction, staining and uniformity of the cytoplasm. There was no statistical difference in the oocytes rate obtained by ovary (FF 11±3.12 vs. FA 11.63±3.74; p> 0.05); however, there were differences in ORT per aspirated follicle (FF 88.13%±16.44 vs. FA 71.50%±14.47; p<0.05) and in the recovery rate of grade A oocytes (FF 27%±10.98 vs. AF 12.75%±8.56; p<0.05). In addition, the FF increased the time to harvest the oocytes due to extra washing (p<0.01). With the data obtained, it can be seen that follicular flushing improved ORT in bovine ovaries, favoring greater recovery of COCs.