Proper oocyte maturation is crucial for subsequent embryo development; however, oocyte mitochondrial and lipid-droplet behaviour are still poorly understood. Although excessive lipid accumulation during in vitro production (IVP) of bovine embryos has been linked with impaired cryotolerance, lipid oxidation is essential for adequate energy supply. Fetal bovine serum (FBS) and bovine serum albumin (BSA) are supplements used during IVP, containing high and low lipid content, respectively. This study aimed to understand how these supplements influence oocyte mitochondrial and lipid behaviour during in vitro maturation (IVM) in comparison to in vivo maturation, as well as their influence on development rates and embryo lipid accumulation during IVP. We demonstrate that only in vivo-matured oocytes maintained correlation between lipid content and active mitochondria. IVM media containing FBS increased total lipid content 18-fold and resulted in higher lipid accumulation in oocytes when compared with media with BSA. IVM using a lower FBS concentration combined with BSA resulted in satisfactory maturation and embryo development and also reduced lipid accumulation in blastocysts. In conclusion, IVM causes changes in mitochondrial and lipid dynamics, which may have negative effects on oocyte development rates and embryo lipid accumulation. Moreover, decreasing FBS concentrations during IVM may reduce embryo lipid accumulation without affecting production rates.

The American continent was colonized in the 16th century by Europeans who first introduced cattle of Bos taurus origin. Accounts register introduction of Bos indicus cattle into South America in the 19th and continuing through the 20th century, and most reported imports were males derived from the Indian subcontinent. In the present study we show, by using mitochondrial DNA (mtDNA) polymorphism, major participation of matrilineages of taurus origin in the American Zebu purebred origin, i.e., 79, 73 and 100% for the Nellore, Gyr and Brahman breeds, respectively. Moreover, we have created a restriction map identifying polymorphism among B. taurus and B. indicus mtDNA using three restriction enzymes. Results are discussed concerning American Zebu origins and potential use of this information for investigating the contribution of cytoplasmic genes in cattle production traits.
O continente americano foi colonizado no século XVI por europeus que fizeram as primeiras introduções de bovinos, de origem taurina. Os registros das primeiras importações de Zebus para a América do Sul datam do século XIX e continuam até o século XX, constituídos na maioria por machos do sub-continente indiano. Neste artigo, demonstramos, através dos estudos de polimorfismos no DNA mitocondrial (mtDNA), uma participação majoritária de matriarcas de origem taurina na formação do Zebu PO americano (79% dos animais analisados da raça Nelore, 73% na Gir e 100% na Brahman). Ainda, criamos um mapa de restrição com os polimorfismos descritos de três enzimas de restrição. Os resultados estão discutidos em termos da origem do Zebu americano e da aplicação deste conhecimento no estudo dos efeitos do genoma citoplasmático, nas características produtivas dos bovinos

No abstract

In recent decades, direct solid sample analysis has been reported in the literature as an alternative to traditional methods of sample preparation, becoming well established in the atomic spectrometry field.

No abstract