Project description:Analysis of key genes and gene networks determining milk productivity of the dairy HF cows Transcriptomes were compared of in the mammary glands of the healthy lactating Holstein Friesian cows of the high- (average 11097 kg milk/lactation) and low- (average 6956 kg milk/lactation) milk yield.
Project description:<p><strong>BACKGROUND:</strong> Lactation is extremely important for dairy cows; however, the understanding of the underlying metabolic mechanisms is very limited. This study was conducted to investigate the inherent metabolic patterns during lactation using the overall biofluid metabolomics and the metabolic differences from non-lactation periods, as determined using partial tissue-metabolomics. We analyzed the metabolomic profiles of four biofluids (rumen fluid, serum, milk and urine) and their relationships in six mid-lactation Holstein cows and compared their mammary gland (MG) metabolomic profiles with those of six non-lactating cows by using gas chromatography-time of flight/mass spectrometry. </p><p><strong>RESULTS:</strong> In total, 33 metabolites were shared among the four biofluids, and 274 metabolites were identified in the MG tissues. The sub-clusters of the hierarchical clustering analysis revealed that the rumen fluid and serum metabolomics profiles were grouped together and highly correlated but were separate from those for milk. Urine had the most different profile compared to the other three biofluids. Creatine was identified as the most different metabolite among the four biofluids (VIP=1.537). Five metabolic pathways, including gluconeogenesis, pyruvate metabolism, the tricarboxylic acid cycle (TCA cycle), glycerolipid metabolism, and aspartate metabolism, showed the most functional enrichment among the four biofluids (false discovery rate<0.05, fold enrichment >2). Clear discriminations were observed in the MG metabolomics profiles between the lactating and non-lactating cows, with 54 metabolites having a significantly higher abundance (P<0.05, VIP>1) in the lactation group. Lactobionic acid, citric acid, orotic acid and oxamide were extracted by the S-plot as potential biomarkers of the metabolic difference between lactation and non-lactation. The TCA cycle, glyoxylate and dicarboxylate metabolism, glutamate metabolism and glycine metabolism were determined to be pathways that were significantly impacted (P<0.01, impact value >0.1) in the lactation group. Among them, the TCA cycle was the most up-regulated pathway (P<0.0001), with 7 of the 10 related metabolites increased in the MG tissues of the lactating cows. </p><p><strong>CONCLUSIONS:</strong> The overall biofluid and MG tissue metabolic mechanisms in the lactating cows were interpreted in this study. Our findings are the first to provide an integrated insight and a better understanding of the metabolic mechanism of lactation, which is beneficial for developing regulated strategies to improve the metabolic status of lactating dairy cows.</p>
Project description:Effect of breed in mid lactation Holstein (H) and Montbéliarde (M) cows on mammary glande miRNA profile. Genetic polymorphisms are known to influence milk production and composition. However, genomic mechanisms involved in the genetic regulation of milk component synthesis are not completely understood. MicroRNAs (miRNA) regulate gene expression. The objective of the present study was to compare mammary gland miRNomes of two dairy cow breeds, Holstein and Montbéliarde, with different dairy performances. Milk, fat, protein, and lactose yields were lower in Montbéliarde than in Holstein cows. MiRNomes obtained using RNA-Seq technology from the mammary glands of Holstein (n = 5) and Montbéliarde (n = 6) lactating cows revealed 623 distinct expressed miRNAs, among which 596 were known and 27 were predicted miRNAs. The comparison of their abundance in the mammary gland of Holstein versus Montbéliarde cows showed 22 differentially expressed miRNAs (Padj ≤ 0.05). Among them, 11 presented a fold change ≥2, with 2 highly expressed miRNAs (miR-100 and miR-146b). Without taking into account the fold change, the differential miRNA with the highest abundance was miR-186, which is known to inhibit cell proliferation and epithelial-to-mesenchymal transition. Data mining showed that the 17 differentially expressed miRNAs with more than 20 reads on average, regulate mammary gland plasticity and may be related to the observed differences in milk production between Holstein and Montbéliarde, which are two breeds with different mammogenic potential. Some of the 17 miRNAs could potentially target mRNAs involved in signaling pathways (such as mTOR) and in lipid metabolism, thereby suggesting that they could influence milk composition. In conclusion, we showed differences in mammary gland miRNomes of two dairy bovine breeds. These differences suggest a potential role of miRNAs in mammary gland plasticity and in milk component synthesis related to milk production and composition.
Project description:Milk protein is one of the most important economic traits in the dairy industry. Yet, the miRNA gene regulatory network for the synthesis of milk protein in mammary is poorly understood. In this study, the hypothesis was that miRNAs have potential roles in bovine milk protein production. Using miRNA-seq and RNA-seq, we investigated the miRNAs profiles of mammary glands from 12 Chinese Holstein cows with six cows at peak of lactation and six in non-lactating period, from which three cows were in high and three in low milk protein percentage.
Project description:Bovine mammary gland provide the largest amount of milk for dairy industry to date. Insight in functional adaptation of this organ is critical in order to improve efficiency of milk synthesis and milk quality. In the present experiment microarray analysis in combination with bioinformatics tools was performed in mammary tissue from 8 Holstein cows during the entire lactation cycle.
Project description:Milk production during the early postpartum in dairy cows can impact the circulating metabolites and negatively affects embryo survival. However, the molecular consequences for the embryo during its development in the oviduct are still unknown. The objective was to determine the impact of metabolic status on embryonic genome activation (EGA) using high-throughput sequencing to generate comprehensive transcriptome profiles of bovine 16-cell stage embryos which had undergone EGA in vitro or in the oviducts of primiparous postpartum dry or postpartum lactating Holstein Friesian cows.
Project description:The aim of this study was to determine the effects of unprotected dietary unsaturated fatty acids (UFA) from different plant oils on gene expression in the mammary gland of grazing dairy cows. Milk composition and gene expression in the mammary gland tissue were evaluated in grazing dairy cows supplemented with different unsaturated fatty acids (UFA). The UFA supplementation improves the health and nutrition quality aspects of dairy milk, but also affects the gene networks expression signature associated with cellular growth and proliferation, cell-death, signalling, nutrient metabolism, and immune response, and in turn, the mammary gland integrity and health. A total of 28 Holstein-Friesian dairy cows in mid-lactation were blocked according to parity (2.4 ± 0.63 years), days in milk (DIM; 153 ± 32.8 days), milk yield (25.7 ± 3.08 kg/d) and fat content (4.3 ± 0.12%). Cows were then randomly assigned to four UFA-sources based on rapeseed, soybean, linseed or a mixture of the three oils for 23 days (Period I) after which, all 28 cows were switched to a control diet for an additional 28 days (Period II). On the last day of both periods, mammary gland biopsies were taken to study genome-wide differences in lipid metabolism gene expression.
Project description:The objective of this study was to characterize the mRNA expression profile in rumen epithelium from Holstein dairy cows fed high or low concentrate dits.
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.
Project description:We investigated changes in rumen fermentation, peripheral blood metabolites and hormones, and hepatic transcriptomic dynamics in Holstein cows with and those without subacute ruminal acidosis (SARA) during the periparturient period.