The Pelibuey sheep has adaptability to climatic variations, resistance to parasites, and good maternal ability, whereas some ewes present multiple births, which increases the litter size in farm sheep. The litter size in some wool sheep breeds is associated with the presence of mutations, mainly in the family of the transforming growth factor β (TGF-β) genes. To explore genetic mechanisms underlying the variation in litter size, we conducted a genome-wide association study in two groups of Pelibuey sheep (multiparous sheep with two lambs per birth vs. uniparous sheep with a single lamb at birth) using the OvineSNP50 BeadChip. We identified a total of 57 putative SNPs markers (p < 3.0 × 10−3, Bonferroni correction). The candidate genes that may be associated with litter size in Pelibuey sheep are CLSTN2, MTMR2, DLG1, CGA, ABCG5, TRPM6, and HTR1E. Genomic regions were also identified that contain three quantitative trait loci (QTLs) for aseasonal reproduction (ASREP), milk yield (MY), and body weight (BW). These results allowed us to identify SNPs associated with genes that could be involved in the reproductive process related to prolificacy.

The Pelibuey sheep (Ovis aries) is an indigenous breed distributed in the tropical regions of Mexico. The prolificacy of this sheep is on average from 1 to 1.5 lambs, being an important breeding characteristic that owners seek to increase with the purpose of economic improvements. New-generation RNA sequencing technology has been used to identify the genes that are expressed in the ovarian tissue of sheep that have two or more lambs per parturition, as well as to elucidate the metabolic pathways that are affected by the expression of these genes, with the purpose of better understanding the prolificacy in the sheep. In the present study, the transcriptional expression of multiparous and uniparous sheep was compared using RNA sequencing. Multiparous (M group) and uniparous (U group) sheep that had a genealogical record for three generations (M, n = 5 and U, n = 5) were selected. RNA was extracted from ovarian tissue and subsequently used to prepare the libraries that were sequenced using the Illumina NextSeq500 platform. A total of 31,575 genes were detected from the transcriptomic analysis of which 4908 were significantly expressed (p-value ≤ 0.001) in the ovary of sheep. Subsequently, a second filter was carried out to evaluate the false discovery rate (FDR) and select those genes with p-values ≤ 0.05 and values of expression ≥ 1 (log2), obtaining 354 differential expressed genes (DEG): 120 genes up-regulated and 234 genes down-regulated in the group M with respect to the group U. Through Gene Ontology (GO) and metabolic analysis, we obtained information on the function of differentially expressed genes, and its importance in the reproduction of multiparous sheep. This result suggest that genes identified in the present study participate in the development of the final stages of follicles.

The FecB mutation in the BMPR1B gene and the G6, G7 and G8 mutations in the GDF9 gene have been documented in Booroola Merino sheep breeds. These mutations have all been identified in several ovine breeds, such as Belclare, Cambridge. Blackbelly hairy sheep breed, which is well adapted to tropical climates due to its African origin, have 2 to 3 lambs per litter, corresponding to a high prolificacy for a tropical breed. The objective of this investigation was to identify mutations in the cDNA of the BMPR1B and GDF9 genes of 20 Blackbelly ewes selected for their prolificacy (two or more lambs by birth). The results of this study indicate the absence of mutations in these genes from the Blackbelly breed. However, it is important to analyze the 3' end region of the cDNA of these genes to rule out the presence or absence of other mutations related to prolificacy. (Mulsant et al., 2001). The FecB mutation in BM-PR1B consists of an A→G transition at nucleotide 746 in the open reading frame and is associated with the hyper-prolific phenotype of the Booroola sheep (Wilson et al., 2001;Souza et al., 2001). This mutation was subsequently reported in other sheep breeds around the world, including the Garole sheep (Polley et al., 2010), Japanese sheep (Davis et al., 2002), the Small Tailed Han sheep (Chu et al., 2007), Hu sheep (Wang et al., 2003) and others (Davis et al., 2006;Hua and Yang 2009). The GDF9 (Growth Differentiation Factor 9) gene maps to chromosome 5 and contains 2 exons (Bodensteiner et al., 1999). The gene extends through a genomic region of approximately 2.5 kb and contains two exons coding for one pro-peptide of 453 amino acids separated by a single intron of 1126 base pairs. In 2004, eight single base mutations (SNP) in the GDF9 gene (G1 to G8) were reported in Cambridge and Belclare ewes (Hanrahan et al., 2004). One mutation is located in exon 1, one is located in an intron and six mutations are in exon 2. Three SNPs do not alter the amino acid sequence; these SNPs are located at position 471 (G2), position 477 (G3) and position 978 (G5). Five of these SNPs result in a change of amino acid sequences (G1, G4, G6, G7 and G8).The objective of this investigation was to identify mutations in the BMPR1B and GDF9 cDNA sequences obtained from 20 Blackbelly ewes selected for their prolificacy. Materials and methods Isolation of total RNAFull blood Blackbelly ewes were selected from the breeding nucleus of Tecnológico de Conkal based on the number of lambs per birth. Twenty of those with a record of two or more lambs in each farrowing were used. Estrus was induced in these ewes over a period of 12 days by applying vaginal sponges impregnated with Chronogest® CR 7 (Flugestone acetate-acetosi-α-fluoro-11-β-hidroxi-pregn-4-ene-3, 20 diona). Two days later, these females were sedated with Ketamin (1.1 mL 50 kg -1 ) for quirurgical intervention, and ovarian tissue was biopsied. These biopsies were preserved in RNAlater and stored at -20 °C before being placed in 0.5 mL of TRIzol reagent (Invitrogen, Carlsbad CA) to be...

The aoudad (Ammotragus lervia) is a wild ruminant considered the living ancestor of domestic sheep and goats. The original distribution of aoudads includes several countries in the North of Africa, but it has been introduced, for trophy-hunting purposes, into other countries (USA, Mexico and Spain).The species was declared vulnerable in the 2012 IUCN's Red List and is also included in the CITES II Appendix. Surprisingly, little is known about its conservation status or the reproductive biology of the natural populations. There are some reports of the application of basic assisted-reproduction techniques in captive aoudads. In this preliminary study, we explored the feasibility of implementing assisted reproduction procedures in captive aoudad females using non-traditional techniques for in vivo embryo production. This approach was used to obtain the best results using the minimum possible number of animals. Three aoudad females were synchronized using a domestic sheep protocol and subcutaneous osmotic pumps for the delivery of follicle-stimulating hormone. A mini-surgical approach combined with laparoscopy was performed to obtain in vivo-produced embryos. All females had an ovulatory response of more than three corporea lutea, but only five good quality morulae were obtained from one female. Those were cryopreserved by vitrification using a Cryotop®. In conclusion, our approach was successful in obtaining in vivo embryos using a limited number of females. Further studies are necessary to optimize the fertilization rate and clarify the effect of our protocol on embryo implantation and the production of offspring.Keywords: Aoudad; Cryotop®; osmotic pumps; superovulation; vitrification, wild ruminant. ResumenAmmotragus lervia, aoudad, es un rumiante silvestre considerando el ancestro de los borregos y cabras domésticas. La distribución original de los aoudad incluye varios países en el Norte de África, pero ha sido introducido, con propósitos de cacería en otros países (EUA, México y España). La especie se declara como vulnerable en la Red List 2012 de la IUCN y también se incluye en el Apéndice II del CITES. Sorprendemente, poco se sabe del estado de conservación o de la biología reproductiva de las poblaciones naturales. Existen algunos reportes de la aplicación de técnicas básicas de reproducción asistida en hembras de aoudad captivas. En este estudio preliminar, exploramos la factibilidad de implementar procedimientos de reproducción asistida en hembras de aoudad captivas usando técnicas no tradicionales para la producción de embriones in vivo. Este enfoque fue utilizado para obtener los mejores resultados utilizando el menor número posible de animales. Tres hembras de aoudad fueron sincronizadas usando un protocolo de borregas domésticas y bombas subcutáneas para la administración de la hormona folículo estimulante. Un abordaje mini-quirúrgico combinado con laparoscopia fue realizado para obtener los embriones producidos in vivo. Todas las hembras tuvieron una respuesta ovulatoria de más de tres cuerp...