Título:	Developmental competence and expression of the Hsp 70.1 gene in oocytes obtained from Bos indicus and Bos taurus dairy cows in a tropical environment.
Autoria:	CAMARGO, L. S. de A. VIANA, J. H. M. RAMOS, A. A. SERAPIÃO, R. V. SÁ, W. F. FERREIRA, A. M. GUIMARÃES, M. F. M. VALE FILHO, V. R. do
Afiliação:	Luiz Sérgio Almeida Camargo, Embrapa Gado de Leite; João Henrique Moreira Viana, Embrapa Gado de Leite; Alessandra A. Ramos, Fiocruz; Raquel Varela Serapião, UENF; Wanderlei Ferreira de Sá, Embrapa Gado de Leite; Ademir de Moraes Ferreira, Embrapa Gado de Leite; Marta Fonseca Martins Guimaraes, Embrapa Gado de Leite; V. R. do Vale Filho, UFMG.
Ano de publicação:	2007
Referência:	Theriogenology, New York, v. 68, n. 4, p. 626-632, 2007.
Conteúdo:	Bos indicus cows usually have better reproductive performance in tropical and subtropical regions than Bos taurus cows, presumably due to their better adaptation to tropical environments. The aim of this study was to evaluate the developmental competence and expression of the Hsp 70.1 gene in immature oocytes from B. taurus (Holstein) and B. indicus (Gyr) dairy cows raised in a tropical region. Cumulus–oocyte complexes were obtained by transvaginal ultrasound-guided follicle aspiration between spring and early autumn, and subjected to in vitro maturation and fertilization. Presumptive zygotes were co-cultured with their own cumulus cells in CR2aa media with 10% fetal calf serum; Grade 1 blastocysts were transferred to synchronized crossbred recipients. The total RNA was extracted from immature Holstein and Gyr oocytes (three pools for each breed) and relative quantification of the Hsp 70.1 transcripts was performed by real time PCR after reverse transcription. Cleavage and blastocyst rates were greater (P < 0.05) for Gyr (n = 390 oocytes) than Holstein (n = 505) breed (66.7% versus 53.1% of cleavage and 19.6% versus 10.8% of blastocysts, respectively), but pregnancy rates were not significantly different following transfer to recipients (44.5% for 36 Gyr embryos; 60% for 10 Holstein embryos). Holstein immature oocytes had a higher level (P < 0.05) of Hsp 70.1 relative expression (1.82 ± 0.22; mean ± S.E.M.) than Gyr oocytes (1.12 ± 0.11). In conclusion, Gyr oocytes obtained in a tropical region were less subject to stress and more likely to develop (after IVF) than Holstein oocytes.
Thesagro:	Bos Indicus
NAL Thesaurus:	heat stress in vitro fertilization
Palavras-chave:	oocyte heat shock protein
Digital Object Identifier:	https://doi.org/10.1016/j.theriogenology.2007.03.029
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CNPGL)