Project description:In this study, we studied the fibrolytic potential of the rumen microbiota in the rumen of 6 lambs separated from their dams from 12h of age and artificially fed with milk replacer (MR) and starter feed from d8, in absence (3 lambs) or presence (3 lambs) of a combination of the live yeast Saccharomyces cerevisiae CNCM I-1077 and selected yeast metabolites. The fibrolytic potential of the rumen microbiota of the lambs at 56 days of age was analyzed with a DNA microarray (FibroChip) targeting genes coding for 8 glycoside hydrolase (GH) families.
Project description:We assessed the transcriptomic adaptation of the calf rumen epithelium to changes in ruminal pH caused by feeding calf starter with and without forage during weaning transition. The calves were divided into a gorage provision group (HAY group, n = 3) and forage non-provision group (CON group, n = 4) 3 weeks after weaning.
Project description:AIMS: To explore and validate the utility of rumen endoscopy for collection of rumen papillae for gene expression measurement. METHODS: Four adult Coopworth ewes were fasted for either 4 or 24 hours. Animals were sedated, placed in a dorsally recumbent position at 45 degrees with the head upright, and an endoscope inserted via a tube inserted into the mouth. Biopsies of rumen papillae were taken from the ventral surface of the rumen atrium under visual guidance. Two biopsies were collected from one of the animals that had been fasted for 4 hours, and three from one of the animals that had been fasted for 24 hours. Video of the rumen atrium and reticulum was also collected. The animals recovered uneventfully. Biopsies were subsequently used for extraction and sequencing of mRNA. RESULTS: The ventral surface of the rumen atrium was accessible after 4 hours off pasture, but a larger region was accessible after 24 hours of fasting. Sedation allowed access for endoscope use for around 5 to 10 minutes after which increased saliva flow was noted. Rumen papillae biopsies were easily collected, with samples from a variety of sites collected in the ∼10 minute time window. High quality RNA was obtained for stranded mRNA sequencing. Of the resulting reads, 69–70% mapped uniquely to version 3.1 of the ovine genome, and 48–49% to a known gene. The rumen mRNA profiles were consistent with a previously reported study. CONCLUSIONS: This method for obtaining rumenal tissue was found to be rapid and resulted in no apparent short or long term effects on the animal. High quality RNA was successfully extracted and amplified from the rumen papillae biopsies, indicating that this technique could be used for future gene expression studies. The use of rumen endoscopy could be extended to collection of a variety of rumen and reticulum anatomical measurements and deposition and retrieval of small sensors from the rumen. Rumen endoscopy offers an attractive and cost effective approach to repeated rumen biopsies compared with serial slaughter or use of cannulated animals.
Project description:The objectives of the study were to use RNA-Seq to examine the effect of (i) breed and (ii) gradual weaning, on the whole blood mRNA transcriptome of artificially reared Holstein-Friesian and Jersey calves. The calves were gradually weaned over 14 days (day (d) -13 to d 0) and mRNA transcription was examined one day before gradual weaning was initiated (d -14), one day after weaning (d 1) and 8 days after weaning (d 8). RNA-seq analysis was carried out on RNA extracted from whole blood. Gradual weaning had no effect on gene expression (P>0.05).There were 550 differentially expressed genes at a false discovery rate of 10% and with a â¥1.5-fold change, between Holstein-Friesian and Jersey calves on d -14, 490 on d 1, and 411 on d 8. GOseq/KEGG pathway analysis showed that the cytokine-cytokine receptor interaction pathway and the neuroactive ligand-receptor interaction pathway were over-represented between breeds on all days (P<0.01; Qâ¤0.1). These results demonstrate that the gradual weaning practiced here does not compromise the welfare of artificially-reared dairy calves, evidenced by the lack of expression changes in any genes in response to gradual weaning. These data also suggest differences in cell signalling and immune responses between breeds. Eight Holstein-Friesian and eight Jersey bull calves were group housed indoors and individually fed milk replacer and concentrate using an automatic feeder. Calves were gradually weaned by reducing milk-replacer from 6 litres to 0 litres over 14 days (d) (d -13 to d 0). Calves were blood sampled on d -14, 1, and 8, relative to weaning (d 0). RNA-seq analysis was carried out on RNA extracted from whole blood.
Project description:As the unique organ, rumen plays vital roles in providing products for humans, however, the underlying cell composition and interactions with epithelium-attached microbes remain largely unknown. Herein, we performed an integrated analysis in single-cell transcriptome, epithelial microbiome, and metabolome of rumen tissues to explore the differences of microbiota-host crosstalk between newborn and adult cattle models. We found that fewer epithelial cell subtypes and more abundant immune cells (e.g., Th17 cells) in the rumen tissue of adult cattle. Metabolism-related functions and oxidation-reduction process were significantly upregulated in the adult rumen epithelial cell subtypes. The epithelial Desulfovibrio was significantly enriched in the adult cattle. To further clarify the role of Desulfovibrio in host’s oxidation-reduction process, we performed metabolomics analysis of rumen tissues and found that Desulfovibrio showed a high co-occurrence probability with the pyridoxal in the adult cattle compared with newborn ones. The adult rumen epithelial cell subtypes also showed stronger ability of pyridoxal binding. These indicates that Desulfovibrio and pyridoxal likely play important roles in maintaining redox balance in adult rumen. The integrated analysis provides novel insights into the understanding of rumen function and facilitate the future precision improvement of rumen function and milk/meat production in cattle.
Project description:We analysed effects of different feeding regimes of milk replacer (MR) during rearing on ovarian physiology with specific emphasis on the numbers of granulosa cells (GCs) as well as gene expression characteristics in GCs at the age of puberty onset. Animals of the 20% feeding group had a significantly higher body weight, but the proportion of animals having a corpus luteum at the time of slaughter was not different between groups, suggesting a similar onset of puberty. Calves of the 10% group showed a constant granulosa cell count regardless of the number of follicles (r = 0.23) whereas in the 20% group increasing numbers of GCs were detected with a higher follicle count (r = 0.71). The mRNA microarray analysis revealed a total of 557 differentially expressed genes in GCs (fold change > |1.5| and p<0.05). Among the top downregulated genes were OAS1X, MX2 and OAS1Z, whereas the top upregulated genes were BOLA, XCL1 and MT1E, which are known to be regulated by interferon. Subsequent signaling pathway analysis revealed the involvement of several immune response mechanisms in accordance with a number of interferons as upstream regulators. The results indicate that the plane of MR feeding in early life have an impact on the number and physiology of GCs later in life. This might influence the overall reproductive life initiated by the onset of puberty in cattle. In addition, the observed alterations in GCs of calves fed less MR might be a consequence of interferon regulated immunological pathways.
Project description:In this study, we investigated the molecular regulatory mechanisms of milk protein production in dairy cows by studying the miRNAomes of five key metabolic tissues involved in protein synthesis and metabolism from dairy cows fed high- and low-quality diets. In total, 340, 338, 337, 330, and 328 miRNAs were expressed in the rumen, duodenum, jejunum, liver, and mammary gland tissues, respectively. Some miRNAs were highly correlated with feed and nitrogen efficiency, with target genes involved in transportation and phosphorylation of amino acid (AA). Additionally, low-quality forage diets (corn stover and rice straw) influenced the expression of feed and nitrogen efficiency-associated miRNAs such as miR-99b in rumen, miR-2336 in duodenum, miR-652 in jejunum, miR-1 in liver, and miR-181a in mammary gland. Ruminal miR-21-3p and liver miR-2285f were predicted to regulate AA transportation by targeting ATP1A2 and SLC7A8, respectively. Furthermore, bovine-specific miRNAs regulated the proliferation and morphology of rumen epithelium, as well as the metabolism of liver lipids and branched-chain AAs, revealing bovine-specific mechanisms. Our results suggest that miRNAs expressed in these five tissues play roles in regulating transportation of AA for downstream milk production, which is an important mechanism that may be associated with low milk protein under lowquality forage feed.