Project description:Samples of perirenal fat tissue from 8 Assaf breed suckling lambs. These animals were selected from a larger group of 17 Assaf suckling lambs for which carcass traits were measured. The 8 selected lambs were those showing the highest and the lowest values, from the larger group, for the percentage of perirenal and cavitary fat relative to the half carcass weight. Hence, considering the values for this trait, we defined the High-PF group (n = 4; average: 3.23 ± 0,.47) and the Low-PF group (n = 4; 1.65 ± 0,.16), respectively.
Project description:In sheep, differences were observed regarding fat accumulation and fatty acid composition between males and females, which may impact the quality and organoleptic characteristics of the meat. The analysis of omics technologies is a relevant approach for investigating biological and genetic mechanisms associated with complex traits. Here, the perirenal tissue of six male and six female Assaf suckling lambs was evaluated using RNA sequencing.
Project description:The aim of this study was to perform a comparative analysis of the perirenal fat transcriptomes of suckling lambs from two breeds with different growth and carcass characteristics. The perirenal fat tissue from 14 suckling lambs (Assaf= 8, Churra= 6) was used for the RNA-Seq analysis. The functional enrichment analysis of the 670 highly expressed genes (>150 fragments per kilobase of exon per million fragments mapped) in the perirenal fat transcriptome of both breeds revealed that the majority of these genes were involved in energy processes. The differential expression analysis performed identified 373 differentially expressed genes (DEGs) between the two compared breeds. In Assaf lambs, DEGs were enriched in Gene Ontology (GO) biological processes related to fatty-acid oxidation, while in Churra lambs, the majority of the significantly enriched GO terms were related to cholesterol synthesis, which suggests that upregulated DEGs in Assaf lambs are implicated in fat burning, while the Churra upregulated DEGs are linked to fat accumulation.
Project description:Purpose: The present study was designed to identify both differentially expressed (DE) genes and differences in proteins accumulated in the liver tissues of suckling female lambs, thus trying to identify modified metabolic pathways as a consequence of milk restriction during the suckling period. Methods: Forty Assaf lambs (average BW 4.7 kg) were penned individually, twenty of them were fed milk replacer (200 g dry matter/L) ad libitum (ADL; 192 mL/kg LBW) whereas the other group (restricted, RES) only received 120 mL/kg LBW. When they were 35 days old, four animals per group were slaughtered (8 lambs in total) and a piece of liver was excised for transcriptomic analysis. The liver transcriptome analysis was carried out using RNA sequencing methodology (RNA-seq). Results: 386 DE genes were identified by RNA-seq, 198 of them being annotated genes in the KEGG pathway. Positive values of log2-fold change (log2FC) indicated that 210 genes were up-regulated in the liver of RES relative to the ADL group, whereas negative log2FC values denoted the down-regulation of 176 genes (P < 0.05). Conclusions: According to the data obtained, a restricted milk intake during the suckling period of replacement lambs affects hepatic transcriptome and proteome associated with an altered metabolism of lipids and proteins, thus reducing feed efficiency of replacement period.
Project description:Purpose: The present study was designed to identify both differentially expressed (DE) genes in the liver tissues of fattening Merino lambs and differences in metabolites accumulated in plasma, thus trying to identify modified metabolic pathways as a consequence of milk restriction during the suckling period. Methods: Twenty-four male Merino lambs were assigned to 2 different groups (n=12 per dietary treatment). The first group (ad libitum, ADL) was kept permanently with the dams whereas the other group (restricted, RES) was milk restricted. When they reached 15 kg of live body weight, all the lambs were offered the same complete pelleted diet at the same level to ensure no differences in dry matter intake. All the lambs were slaughtered with 27 kg. For transcriptomic analysis, 4 liver samples representative from each group (8 samples in total) were selected for RNA sequencing methodology (RNA-seq). Results: 38 DE annotated genes were identified by RNA-seq, with 23 DE genes being down-regulated and 15 up-regulated in the liver of RES relative to the ADL group (P < 0.10). In general, those genes and pathways involved in protein synthesis or protease inhibitors were down-regulated in the RES group, whereas those related to proteolytic degradation were up-regultated, thus suggesting a higher catabolism of proteins in these lambs. Contrarily, RES lambs showed over-expression of xenobiotic metabolism pathways, whereas those genes related to β-oxidation of fatty acids were down expressed. Conclusions: According to the data obtained, early feed restriction during the suckling period of Merino lambs promoted long-term effects on hepatic transcriptomic profile and plasma metabolic profile wich might have modified fatty acids metabolism, catabolism of proteins and detoxification of xenobiotics, thus reducing feed efficiency of fattening period.
Project description:Feed restriction during the early life of ewe lambs (F0) triggers the transfer of epigenetic marks to the next generation, thus impairing the reproductive performance of F1. However, the effects of this factor on milk production and composition, including its abundance in regulatory miRNA (many of which are contained in exosomes, small vesicles of endocytic origin that play a role in the modulation of immune response of the offspring), has not been tested so far. Therefore, in this study, the replacement ewe lambs (F0) obtained in a previous project (a group of ewes fed milk replacer ad libitum –ADL– vs. a group of ewes restricted –RES– to 62.5% the intake level of milk replacer during the suckling period) were raised under similar post-weaning conditions and mated to obtain the progeny (F1). The F1 dairy ewes were also mated, and six of these F1 dairy ewes were selected and divided into two groups: the F1-ADL group (n=3) born from F0-ADL and the F1-RES group (n=3), born from F0-RES animals. Milk production was controlled during the peak lactation period, and milk samples were obtained for each gland separately to measure chemical composition, somatic cell counts, and bacteriology. Exosomes were also isolated for each gland separately to define the miRNA content. The miRNAome was determined following a Next Generation Sequencing approach. The first preliminary results indicate significant differences in the abundance of five miRNAs in the milk obtained during the peak of lactation. Thus, oar-miR-150, oar-miR-221, oar-miR-23a, oar-miR-27a, oar-miR-376c were all down modulated in F1-RES when compared to F0-ADL. Most of these miRNAs have been found to play a role in biological functions such as development, apoptosis, muscle differentiation, reproduction, or milk production. Moreover, somatic cell count (SCC) was reduced significantly in milk samples during the peak of lactation of F1-RES dairy sheep. No significant differences were found in milk production, the chemical composition of milk (fat, protein, lactase), or bacteriology (colony forming units, CFU). This study's results provide some evidence of the effects of nutritional programming events on the milk's bioactive components.
Project description:In sheep, differences were observed regarding fat accumulation and fatty acid (FA) composition between males and females, which may impact the quality and organoleptic characteristics of the meat. The integration of different omics technologies is a relevant approach for investigating biological and genetic mechanisms associated with complex traits. Here, the perirenal tissue of six male and six female Assaf suckling lambs was evaluated using RNA sequencing and whole-genome bisulfite sequencing (WGBS). A multiomic discriminant analysis using multiblock (s)PLS-DA allowed the identification of 314 genes and 627 differentially methylated regions (within these genes), which perfectly discriminate between males and females. These candidate genes overlapped with previously reported QTLs for carcass fat volume and percentage of different FAs in milk and meat from sheep. Additionally, differentially coexpressed (DcoExp) modules of genes between males (nine) and females (three) were identified that harbour 22 of these selected genes. Interestingly, these DcoExp were significantly correlated with fat percentage in different deposits (renal, pelvic, subcutaneous and intramuscular) and were associated with relevant biological processes for adipogenesis, adipocyte differentiation, fat volume and FA composition. Consequently, these genes may potentially impact adiposity and meat quality traits in a sex-specific manner, such as juiciness, tenderness and flavour.