- Email: [email protected]
Developmental capacity of cumulus oocyte complexes collected from prepubertal cattle with and without gonadotropin stimulation employing ultrasound-guided follicular aspiration
Theriogenology
323
DEVELOPMENTAL CAPACITY OF CUMULUS OOCYTE COMPLEXES COLLECTED FROM PREPUBERTAL CATrLE WITH AND WITHOUT GONADOTROPIN STIMULATION EMPLOYING ULTRASOUND-GUIDED FOLLICULAR ASPIRATION A. KUWER, E. LEMME and H. NIEMANN Dept. of Biotechnology, Institut f'tirTierzucht und Tierverhalten (FAL) Mariensee, 31535 Neustadt, Germany Ultrasound-guided follicular aspiration (OPU) allows repeated collection of viable cumulus oocyte complexes (COC) from prepul~n'talcattle (Theriogenology 45, 356, 1996). However, the developmental capacity of these oocytes is reduced compared to their counterparts recovered from adult animals. The purpose of this study was to test several superovulatory treatment schedules in their ability to increase the yields of developmentallycompetent oocytes and to improve the efficiency in generating U:ansferableblastccysts. Ultrasound-guided follicular aspir~on was conducted twiceper week in 3 groups (each with 4-6 animals) of 5 to 8 six months old Holstein Friesian cattleover a period of six weeks. Harvested COC were classified into five different categories according to morphological quality. IVM-IVF-IVC were performed in TCM 199 supplemented with hormones and BSA (Therbgenology 43, 667-675, 1995). Representative samples were assessed for maturationand fe'rtdizationand the remaining COC were cultured unfilday 7. The diameter of a representative sample of oocytes was measmed. Some transferable blastocysts were transferred'to synchronizedrecipients. Following Irealmentwith 1000 I.U. PMSG once per week (Exp. 1) an average of 3.8 oocytes was colleaed whereas non-treated calves yielded only 2.7 oocytes. The percentage of oocytes which reached the morula- and blastocyst stage at day 7 was 3.9% in non-treated animals and 16.2% (p<0.05) in superovulatxt calve~ After treatmentusing a combination of 500 I.U. PMSG and 50 mg FSH administered in an alternating manner, oocyte yields were similar in treated and non-treated animals (7.1 vs. 6.8 oocytes per donor) (Exp. 2). From the COC collected from non-lreated controls 12.8% developed to morulae/blastocysts vs. 17.7% of the oocytes from superovulated animals. Following treatn-ent with 50 mg FSH (Exp. 3) administered 48 hrs prior to each OPU-session no differences were seen in oocyte yields between stimulated and non-stimulated animals (6.8 vs. 6.7 oocytes per donor). Significantly more COC developed to morula and blastocyst stages in superovulated calves versus non-treated controls (12.2% vs. 4.3%). Maturaion rate (oocytes reachkLg the metaphase II stage) was similar between oocytes from controls and superstimulated animals (86.8% vs. 85.5%). Similarly, nomaalfertilization was not different between COC from controls and gonadotropin treated animals (59.3% vs. 53.3%), but in both groups a high percentage of polyspermy (32.4% vs. 43.2%) was observed. The average diameter of oocytes was similar between oocytes from non-stimulated animals (118.3 1am) and sfimuhted animals (119.7 ~m) while the average diame~ of COC from aduk animals was significantly greater (123.3 1am). Following transfer of 36 embryos to 24 recipients six pregnancies were obtained. One pregnancy resulted from the transfer of embryos from non-slimulated conlrols. Unfortunately, the female calf (71 kg) died during parturition. Two recipients aborted and three pregnancies resuled in the delivery of three living bull calves. Theseresul~s show that treamlentwith gonadotropin improves quality of COC from prepubertal cattle whereas the number of follicles is not enhanw.d. Further studies are currently underway to elucidate the high perceraage of polyspermy and to increase the developmentalcapacity of blastocysts from prepubertal cattle upon transfer to recipients.
323
DEVELOPMENTAL CAPACITY OF CUMULUS OOCYTE COMPLEXES COLLECTED FROM PREPUBERTAL CATrLE WITH AND WITHOUT GONADOTROPIN STIMULATION EMPLOYING ULTRASOUND-GUIDED FOLLICULAR ASPIRATION A. KUWER, E. LEMME and H. NIEMANN Dept. of Biotechnology, Institut f'tirTierzucht und Tierverhalten (FAL) Mariensee, 31535 Neustadt, Germany Ultrasound-guided follicular aspiration (OPU) allows repeated collection of viable cumulus oocyte complexes (COC) from prepul~n'talcattle (Theriogenology 45, 356, 1996). However, the developmental capacity of these oocytes is reduced compared to their counterparts recovered from adult animals. The purpose of this study was to test several superovulatory treatment schedules in their ability to increase the yields of developmentallycompetent oocytes and to improve the efficiency in generating U:ansferableblastccysts. Ultrasound-guided follicular aspir~on was conducted twiceper week in 3 groups (each with 4-6 animals) of 5 to 8 six months old Holstein Friesian cattleover a period of six weeks. Harvested COC were classified into five different categories according to morphological quality. IVM-IVF-IVC were performed in TCM 199 supplemented with hormones and BSA (Therbgenology 43, 667-675, 1995). Representative samples were assessed for maturationand fe'rtdizationand the remaining COC were cultured unfilday 7. The diameter of a representative sample of oocytes was measmed. Some transferable blastocysts were transferred'to synchronizedrecipients. Following Irealmentwith 1000 I.U. PMSG once per week (Exp. 1) an average of 3.8 oocytes was colleaed whereas non-treated calves yielded only 2.7 oocytes. The percentage of oocytes which reached the morula- and blastocyst stage at day 7 was 3.9% in non-treated animals and 16.2% (p<0.05) in superovulatxt calve~ After treatmentusing a combination of 500 I.U. PMSG and 50 mg FSH administered in an alternating manner, oocyte yields were similar in treated and non-treated animals (7.1 vs. 6.8 oocytes per donor) (Exp. 2). From the COC collected from non-lreated controls 12.8% developed to morulae/blastocysts vs. 17.7% of the oocytes from superovulated animals. Following treatn-ent with 50 mg FSH (Exp. 3) administered 48 hrs prior to each OPU-session no differences were seen in oocyte yields between stimulated and non-stimulated animals (6.8 vs. 6.7 oocytes per donor). Significantly more COC developed to morula and blastocyst stages in superovulated calves versus non-treated controls (12.2% vs. 4.3%). Maturaion rate (oocytes reachkLg the metaphase II stage) was similar between oocytes from controls and superstimulated animals (86.8% vs. 85.5%). Similarly, nomaalfertilization was not different between COC from controls and gonadotropin treated animals (59.3% vs. 53.3%), but in both groups a high percentage of polyspermy (32.4% vs. 43.2%) was observed. The average diameter of oocytes was similar between oocytes from non-stimulated animals (118.3 1am) and sfimuhted animals (119.7 ~m) while the average diame~ of COC from aduk animals was significantly greater (123.3 1am). Following transfer of 36 embryos to 24 recipients six pregnancies were obtained. One pregnancy resulted from the transfer of embryos from non-slimulated conlrols. Unfortunately, the female calf (71 kg) died during parturition. Two recipients aborted and three pregnancies resuled in the delivery of three living bull calves. Theseresul~s show that treamlentwith gonadotropin improves quality of COC from prepubertal cattle whereas the number of follicles is not enhanw.d. Further studies are currently underway to elucidate the high perceraage of polyspermy and to increase the developmentalcapacity of blastocysts from prepubertal cattle upon transfer to recipients.