RESUMO
The research has shown the interesting contributions of shearing in mid-gestation on the performance of lambs from birth to weaning. Other studies have reported that shearing at early pregnancy influences the development of the placenta and lamb live weight at birth. However, there was a lack of information on the effect of early-prepartum shearing on the behavior of the offspring from weaning onward. This study evaluated the effect of shearing ewes at 50 days of gestation on the growth, reproductive behavior and response to a gastrointestinal parasite challenge in the female offspring from weaning to 18 months old. Fifty-seven Polwarth female lambs were used, 22 being singles and 35 twins born to ewes either shorn at 50 days of pregnancy (PS, n = 23) or shorn at 62 days postpartum (U, control, n = 34) resulting in four subgroups: single lambs born to PS ewes (n = 8), born to U ewes (n = 14), twin lambs born to PS ewes (n = 15) or born to U ewes (n = 20). All progeny were managed together under improved pasture with a minimum forage allowance of 6% live weight on dry basis. Body weight, body condition score and fecal eggs count were recorded every 14 days from weaning to 18 months of age. Concentrations of progesterone were measured weekly (from 4 to 10 months of age and from 14 to 18 months of age) to establish the onset of puberty. Ovulation rate at an induced and a natural heat (545 ± 1.0 and 562 ± 1.0 day old) was recorded. Prepartum shearing did not affect the age at puberty or the ovulation rate of female offspring, but those born as singles were more precocious ( P = 0.03) and heavier ( P = 0.02) at puberty than twin born lambs. Both the average value of parasite egg count ( P = 0.0 7) and the Famacha index ( P = 0.02) for the entire study period were lower in lambs born to prepartum shorn ewes than those born to postpartum shorn ewes. In conclusion, shearing at 50 days of gestation did not affect the growth or the reproductive behavior of female offspring. However, female lambs born from ewe shorn during gestation showed a better response to the parasitic challenge, and further research is required to confirm this.
Assuntos
Comportamento Sexual Animal , Ovinos/fisiologia , Animais , Feminino , Parto , Período Pós-Parto , Gravidez , Ovinos/crescimento & desenvolvimento , Desmame , Lã/fisiologiaRESUMO
Wool is produced via synthetic processes of wool follicles, which are embedded in the skin of sheep. The development of new-generation sequencing and RNA sequencing provides new approaches that may elucidate the molecular regulation mechanism of wool follicle development and facilitate enhanced selection for wool traits through gene-assisted selection or targeted gene manipulation. We performed de novo transcriptome sequencing of skin using the Illumina Hiseq 2000 sequencing system in sheep (Ovis aries). Transcriptome de novo assembly was carried out via short-read assembly programs, including SOAPdenovo and ESTScan. The protein function, clusters of orthologous group function, gene ontology function, metabolic pathway analysis, and protein coding region prediction of unigenes were annotated by BLASTx, BLAST2GO, and ESTScan. More than 26,266,670 clean reads were collected and assembled into 79,741 unigene sequences, with a final assembly length of 35,447,962 nucleotides. A total of 22,164 unigenes were annotated, accounting for 36.27% of the total number of unigenes, which were divided into 25 classes belonging to 218 signaling pathways. Among them, there were 17 signal paths related to hair follicle development. Based on mass sequencing data of sheepskin obtained by RNA-Seq, many unigenes were identified and annotated, which provides an excellent platform for future sheep genetic and functional genomic research. The data could be used for improving wool quality and as a model for human hair follicle development or disease prevention.
Assuntos
Carneiro Doméstico/genética , Pele/metabolismo , Transcriptoma , Lã/fisiologia , Animais , Mapeamento de Sequências Contíguas , Etiquetas de Sequências Expressas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Biblioteca Gênica , Genômica , Modelos Genéticos , Anotação de Sequência Molecular , Análise de Sequência de RNARESUMO
This study characterized the population of wool ewes in the highlands of the State of Puebla, Mexico, considering traits such as fleece color, weight, and body measurements. In this region, dominated by a temperate climate, sheep are a traditional animal species for farming systems. To carry out the work, 2,082 ewes were randomly selected from 14 communities and 124 flocks belonging to the six municipalities that have the largest inventory of sheep in the state. For each ewe, live weight, breed, fleece color pattern, and 18 other body measurements were recorded. Descriptive statistics were estimated for weight and body traits and the morphotype was classified by multivariate analysis. Factor analysis identified the bulk, size, and breed standard as the attributes that best describe the population of ewes. These elements varied in importance among the groups (p < 0.05). Cluster analysis helped to classify the population into small black-faced ewes (28.5 %), small white ewes (11.9 %), black-faced medium-sized ewes (24.1 %), large ewes (12.3 %), and white medium-sized ewes (23.2 %). The groups identified were similar to creole sheep present in rural communities in other environments, but have lower morphostructural values than specialized breeds.
Assuntos
Tamanho Corporal , Carneiro Doméstico/fisiologia , Lã/fisiologia , Criação de Animais Domésticos , Animais , Peso Corporal , Análise por Conglomerados , Feminino , México , Fenótipo , Pigmentação , Carneiro Doméstico/anatomia & histologia , Carneiro Doméstico/genética , Especificidade da EspécieRESUMO
The white coat colour of sheep is an important economic trait. For unknown reasons, some animals are born with, and others develop with time, black skin spots that can also produce pigmented fibres. The presence of pigmented fibres in the white wool significantly decreases the fibre quality. The aim of this work was to study gene expression in black spots (with and without pigmented fibres) and white skin by microarray techniques, in order to identify the possible genes involved in the development of this trait. Five unrelated Corriedale sheep were used and, for each animal, the three possible comparisons (three different hybridisations) between the three samples of interest were performed. Differential gene expression patterns were analysed using different t-test approaches. Most of the major genes with well-known roles in skin pigmentation, e.g. ASIP, MC1R and C-KIT, showed no significant difference in the gene expression between white skin and black spots. On the other hand, many of the differentially expressed genes (raw P-value < 0.005) detected in this study, e.g. C-FOS, KLF4 and UFC1, fulfil biological functions that are plausible to be involved in the formation of black spots. The gene expression of C-FOS and KLF4, transcription factors involved in the cellular response to external factors such as ultraviolet light, was validated by quantitative polymerase chain reaction (PCR). This exploratory study provides a list of candidate genes that could be associated with the development of black skin spots that should be studied in more detail. Characterisation of these genes will enable us to discern the molecular mechanisms involved in the development of this feature and, hence, increase our understanding of melanocyte biology and skin pigmentation. In sheep, understanding this phenomenon is a first step towards developing molecular tools to assist in the selection against the presence of pigmented fibres in white wool.