Current strategies for in vitro embryo production (IVP) include OPU on random day of estrous cycle. Oocytes recovered are heterogeneous in chromatin configuration, oocyte-cumulus coupling, transcriptional activity and developmental competence. Since oocyte in vitro maturation (IVM) should promote synchrony between nuclear and cytoplasmic maturation, this heterogeneity may underlie the low efficiency of current IVP strategies. This study aimed to characterize oocyte population obtained by OPU and to develop a protocol to synchronize oocytes destined to IVP in Nellore. In experiment 1, 14 Nellore cows were subjected to two treatments in crossover design: 1) OPU at random day (Control); 2) aspiration of follicles >2mm at random day (D0), two IM injections of FSH (Folltropin; 24+16mg) 10h apart on D2, OPU from follicles >2mm on D5 (ASP/FSH-40). In experiment 2, 12 Nellore cows were subjected to the same treatments as in experiment 1, except for reduction of FSH dose (Folltropin; 12+8mg) (ASP-FSH/20). At OPU, antral follicles were counted and classified as small (3-5mm), medium (6-8mm) and large (>8mm). Oocytes were counted, fixed and stained with Hoechst 33342 then examined by fluorescence microscopy to be classified according with chromatin condensation and germinal vesicle configuration in GV0, GV1, GV2, GV3 and GVBD (Lodde et al., 2007). Data were arcsine transformed and groups compared by paired T test (P<0.05). Total number of follicles aspirated at OPU was not affected by treatment in any experiments. In experiment 1, 285 follicles were aspirated in Control group and 306 in Asp/FSH-40 group, while in experiment 2, total numbers 468 and 463 follicles were aspirated in Control and ASP-FSH/20 groups, respectively. However, in experiment 1, ASP-FSH/40 treatment reduced percentage of small follicles (P=0.02). Percentages of small, medium and large follicles were 67.6*, 24.1 and 8.3 in Control, and 50*, 35.4 and 14.6 in ASP-FSH/40, respectively. Distribution of oocytes in different categories of chromatin compaction was only affected by treatment in experiment 2, with ASP-FSH/20 reducing the percentage of GV3 oocytes (P=0.01). In experiment 1, percentages of GV0, GV1, GV2, GV3, GVBD and degenerated oocytes in Control group were 1.34, 0.25, 39.06, 46.37, 0.12 and 12.86 respectively (n=177), while they were 0, 4.14, 40.49, 38.94, 0 and 16.42 in ASP-FSH/40 respectively (n=195). In experiment 2, percentages of GV0, GV1, GV2, GV3, GVBD and degenerated oocytes were 0, 1.95, 47.55, 40.47*, 0 and 10.03 in Control group respectively (n=267), while they were 0, 4.22, 49.53, 30.50*, 0 and 15.75 in ASP-FSH/40 respectively (n=265). In conclusion, oocytes recovered by OPU at a random day in Nellore were mostly at intermediate (GV2) or advanced (GV3) stage of chromatin compaction. Since these stages have been associated with higher developmental competence, this finding may help to explain the suitability of the Nellore breed to IVP. Protocols combining antral follicle aspiration and low doses of FSH to stimulate follicle recruitment may further homogenize the oocyte population for OPU in Nellore. However, further improvement of ASP-FSH protocols and fine-tuning with IVM culture system are needed before their real impact on IVP outcomes can be determined. FAPESP, CAPES.

Characterization and control of the oocyte population for ovum pick up in Nellore donors / J.N. Sakoda, A.C.S. Soares, I.L.G.C.L. Martins, V. Lodde, A.M. Luciano, J. Buratini. - In: ANIMAL REPRODUCTION. - ISSN 1806-9614. - 15:1(2018 Sep), pp. 1144-1144. ((Intervento presentato al 10. convegno IRRS International Ruminant Reproduction Symposium : September 16th to 20th tenutosi a Foz do Iguaçu (PR, Brazil) nel 2018.

Characterization and control of the oocyte population for ovum pick up in Nellore donors

V. Lodde
Membro del Collaboration Group
;
A.M. Luciano
Penultimo
Membro del Collaboration Group
;
2018

Abstract

Current strategies for in vitro embryo production (IVP) include OPU on random day of estrous cycle. Oocytes recovered are heterogeneous in chromatin configuration, oocyte-cumulus coupling, transcriptional activity and developmental competence. Since oocyte in vitro maturation (IVM) should promote synchrony between nuclear and cytoplasmic maturation, this heterogeneity may underlie the low efficiency of current IVP strategies. This study aimed to characterize oocyte population obtained by OPU and to develop a protocol to synchronize oocytes destined to IVP in Nellore. In experiment 1, 14 Nellore cows were subjected to two treatments in crossover design: 1) OPU at random day (Control); 2) aspiration of follicles >2mm at random day (D0), two IM injections of FSH (Folltropin; 24+16mg) 10h apart on D2, OPU from follicles >2mm on D5 (ASP/FSH-40). In experiment 2, 12 Nellore cows were subjected to the same treatments as in experiment 1, except for reduction of FSH dose (Folltropin; 12+8mg) (ASP-FSH/20). At OPU, antral follicles were counted and classified as small (3-5mm), medium (6-8mm) and large (>8mm). Oocytes were counted, fixed and stained with Hoechst 33342 then examined by fluorescence microscopy to be classified according with chromatin condensation and germinal vesicle configuration in GV0, GV1, GV2, GV3 and GVBD (Lodde et al., 2007). Data were arcsine transformed and groups compared by paired T test (P<0.05). Total number of follicles aspirated at OPU was not affected by treatment in any experiments. In experiment 1, 285 follicles were aspirated in Control group and 306 in Asp/FSH-40 group, while in experiment 2, total numbers 468 and 463 follicles were aspirated in Control and ASP-FSH/20 groups, respectively. However, in experiment 1, ASP-FSH/40 treatment reduced percentage of small follicles (P=0.02). Percentages of small, medium and large follicles were 67.6*, 24.1 and 8.3 in Control, and 50*, 35.4 and 14.6 in ASP-FSH/40, respectively. Distribution of oocytes in different categories of chromatin compaction was only affected by treatment in experiment 2, with ASP-FSH/20 reducing the percentage of GV3 oocytes (P=0.01). In experiment 1, percentages of GV0, GV1, GV2, GV3, GVBD and degenerated oocytes in Control group were 1.34, 0.25, 39.06, 46.37, 0.12 and 12.86 respectively (n=177), while they were 0, 4.14, 40.49, 38.94, 0 and 16.42 in ASP-FSH/40 respectively (n=195). In experiment 2, percentages of GV0, GV1, GV2, GV3, GVBD and degenerated oocytes were 0, 1.95, 47.55, 40.47*, 0 and 10.03 in Control group respectively (n=267), while they were 0, 4.22, 49.53, 30.50*, 0 and 15.75 in ASP-FSH/40 respectively (n=265). In conclusion, oocytes recovered by OPU at a random day in Nellore were mostly at intermediate (GV2) or advanced (GV3) stage of chromatin compaction. Since these stages have been associated with higher developmental competence, this finding may help to explain the suitability of the Nellore breed to IVP. Protocols combining antral follicle aspiration and low doses of FSH to stimulate follicle recruitment may further homogenize the oocyte population for OPU in Nellore. However, further improvement of ASP-FSH protocols and fine-tuning with IVM culture system are needed before their real impact on IVP outcomes can be determined. FAPESP, CAPES.
English
Settore VET/01 - Anatomia degli Animali Domestici
Settore VET/02 - Fisiologia Veterinaria
Settore VET/10 - Clinica Ostetrica e Ginecologia Veterinaria
Settore BIO/06 - Anatomia Comparata e Citologia
Riassunto di intervento a convegno
Esperti anonimi
Ricerca di base
Pubblicazione scientifica
set-2018
Colégio Brasileiro de Reprodução Animal
15
1
1144
1144
1
Pubblicato
Periodico con rilevanza internazionale
IRRS International Ruminant Reproduction Symposium : September 16th to 20th
Foz do Iguaçu (PR, Brazil)
2018
10
SBTE
Convegno internazionale
Intervento inviato
Aderisco
info:eu-repo/semantics/article
Characterization and control of the oocyte population for ovum pick up in Nellore donors / J.N. Sakoda, A.C.S. Soares, I.L.G.C.L. Martins, V. Lodde, A.M. Luciano, J. Buratini. - In: ANIMAL REPRODUCTION. - ISSN 1806-9614. - 15:1(2018 Sep), pp. 1144-1144. ((Intervento presentato al 10. convegno IRRS International Ruminant Reproduction Symposium : September 16th to 20th tenutosi a Foz do Iguaçu (PR, Brazil) nel 2018.
reserved
Prodotti della ricerca::01 - Articolo su periodico
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266
Article (author)
si
J.N. Sakoda, A.C.S. Soares, I.L.G.C.L. Martins, V. Lodde, A.M. Luciano, J. Buratini
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/616162
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