Ovum pick up in swine: the influence of aspiration vacuum pressure on oocyte recovery from preovulatory follicles
Brüssow, K.P.; Torner, H.; Rátky, J.; Hunter, M.G.; Nürnberg, G.
Acta Veterinaria Hungarica 45(2): 189-196
1997
ISSN/ISBN: 0236-6290 PMID: 9270141 Document Number: 471457
Oestrus was synchronized in 33 crossbred Landrace gilts by feeding altrenogest, and follicle growth was stimulated with 1000 IU PMSG 24 h after the last altrenogest application. On day 4 after PMSG, preovulatory healthy follicles of >5 mm diameter were aspirated laparoscopically using a two-way cannula and an electronic aspiration pump. Five different vacuum pressures were used (10, 17, 32, 47 and 66 ml water/min., corresponding to 30, 60, 125, 250 and 375 mm Hg respectively). Fluids from different follicles were pooled per ovary and the morphology of cumulus oocyte complexes (COCs) was determined microscopically immediately after aspiration. COCs were classified into those with oocytes with an intact cumulus (i.e. compact or slightly expanded COC) and those with corona radiata and denuded oocytes. A total of 695 follicles were aspirated and 501 COCs recovered. Increasing the aspiration pressure stepwise from 10 to 66 ml water/min resulted in a decrease in oocyte recovery rate. A higher (P<0.05) rate of oocyte recovery (77.4 vs. 59.8%) was achieved using a vacuum pressure of 17 ml water/min. compared to 66 ml water/min. respectively. There was a tendency to reduce the percentage of COCs with an intact cumulus from 82-88 to 77% if the vacuum pressure increased to >47 ml water/min. A higher aspiration pressure increased (P<0.05) the percentage of denuded oocytes from 0-3 at 10-32 ml water/min to 10 at 47 ml water/min and 17 at 66 ml water/min. The results showed that an aspiration vacuum pressure of 17-32 ml water/min was optimal for oocyte recovery and COC quality in pigs.