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.

El objetivo de este estudio fue determinar la influencia de un alimento fermentado, elaborado con semillas de Canavalia ensiformis, sobre el comportamiento productivo y características de la canal de ovinos Pelibuey (n= 18). El diseño utilizado fue completamente al azar con dos factores con medidas repetidas en un factor. Los factores fueron tipo de dieta [alimento sin fermentar con canavalia (SFC), alimento fermentado con canavalia (FC), alimento sin fermentar y sin canavalia (SFSC)] y número de periodo de evaluación. Se evaluó peso vivo (PV), ganancia diaria de peso (GDP), consumo diario de materia seca, proteína cruda y energía metabolizable, así como peso y rendimiento de la canal. El tipo de dieta, número de período y la interacción tipo de dieta x número de período afectaron (P<0.01) el consumo de todos los nutrimentos estudiados, PV y GDP. El tipo de dieta afectó (P<0.01) el peso de la canal. La dieta FC permitió una mayor GDP (P<0.01) con respecto a la dieta SFC. Los ovinos alimentados con la dieta SFSC fueron los que mostraron la mayor GDP (P<0.05). En conclusión, la alimentación de ovinos con dietas con harina de semillas de canavalia permitió cambios positivos en el crecimiento y peso de la canal.Sin embargo, estos cambios fueron de menor magnitud con respecto a los obtenidos con una dieta sin semillas de canavalia.

Leaf share, plant age and growth season are often overlooked as modifiers of the biomass quality in energy crops. The current work studied the effect of the given factors on the biomass yield and the biomass quality in Elephant grass CT115, intended for bioethanol production, in Veracruz, Mexico. Two seasons per year, 5 months each, were tracked on a 2-weeks basis. The climate is warm wet with summer rains, 1,142 mm of annual rainfall, and 26 °C monthly temperature. From day 56 of the wet season or from day 84 of the dry season, stems accumulated 12 or 6 Mg ha−1, respectively, while green leaves increased only 1 Mg. Higher biomass quality was recorded for the leaf fraction, or for the wet season regrowth. For instance, lignin contained in stems meant twice that of leaves, whereas stems recorded 20% less lignin in the wet season as compared to the dry season. Despite holocellulose being similar between fractions or seasons, hemicellulose and cellulose showed inverse correlation, while lignin and cellulose contents were directly correlated in stems. Increasing the annual harvest of green leaves will improve biomass quality, which is known to increase biodegradability and might improve the annual ethanol yield.

The runs of homozygosity (ROHs), the inbreeding coefficient, and the effective population size (Ne) in Pelibuey sheep were analyzed in 24 Pelibuey ewes from two lambs at parturition and 24 ewes that gave birth to a single lamb using the Ilumina OvineSNP50 BeadChip. The Ne decreased from 535 to 192 in the first ten generations. A total of 2194 ROHs were identified on the basis of single nucleotide polymorphisms (SNPs), were identified in the prolific group and 2185 SNPs in ROH in the non-prolific group. The distribution of the lengths of the ROH, considering both groups, were found to be: 4065 less than 6 Mb, 213 between 6 and 12 Mb, 72 between 12 and 24 Mb, twenty between 24 and 48 Mb and 8 greater than 48 Mb. In prolific sheep, the ROH associated with prolificacy were identified near the LINGO2, FLRT2, ADGRB3 genes, related to “positive regulation of synapse assembly”; and the DGKG, DGKE, DGKB and DGKI genes, related to “protein kinase C-activating G-protein coupled receptor signaling pathway”. The present work present genes that can function as signal mediators or have activity in embryonic development, which is relevant to the economic activity of this species.