Project description:We investigated miRNA expression in Holstein dairy cow of mammary gland with different producing quality milk using high-throughput sequence and qRT-PCR techniques. miRNA libraries were constructed from mammary gland tissues taken from a high producing quality milk and a low producing quality milk Holstein dairy cow, the small RNA digitalization analysis based on HiSeq high-throughput sequencing takes the SBS-sequencing by synthesis.The libraries included 4732 miRNAs. A total of 124 miRNAs in the high producing quality milk mammary gland showed significant differences in expression compared to low producing quality milk mammary gland (P<0.05). Conclusion: Our study provides a broad view of the bovine mammary gland small RNA expression profile characteristics. Differences in types and expression levels of miRNAs were observed between high producing quality milk and a low producing quality milk Holstein dairy cow
Project description:Mastitis, the inflammation of the mammary gland, is one of the most prevalent diseases in dairy farming worldwide. Unfortunately, the disease is most often present in a subclinical type with no clear symptoms. The sooner the infection is detected, the less opportunities for the disease to progress and the more treatment options remain available. Milk microRNA (miRNA) encapsulated in extracellular vesicles (EV) have been proposed as potential biomarkers of different mammary gland conditions, including subclinical mastitis. However, little is known about the robustness of EV analysis regarding sampling time-point or natural infections. In order to estimate the reliability of EV measurements in raw bovine milk, we first evaluated the changes in EV size, concentration and miRNA cargo during three consecutive days. Then, we compared milk EV differences from natural infected quarters with high somatic cell count (SCC) with their healthy adjacent quarters with low SCC and quarters from uninfected udders. We found that milk EV miRNA cargo is very stable along three days and that infected quarters do not induce relevant changes in milk EV of adjacent healthy quarters, making them suitable controls. We observed cow-individual changes in immunoregulatory miRNA in quarters with chronic subclinical mastitis, pointing towards infection-specific alterations. Finally, we proposed bta-miR-223 as a potential indicator of subclinical mastitis prognosis in raw milk.
Project description:Given that different diets could alter cow milk yield and composition, the effects of different feed formula on milk extracellular vesicle (EV) miRNAs were detected. Cow milk EVs contained various small RNAs, including miRNAs, snRNAs, tiRNAs, Cis-regulatory elements, and piRNAs. Two hundred and seventy-six known bos taurus miRNAs were identified by sequencing in bovine milk EVs. There were 13 immune-related miRNAs in the top 20 miRNAs in milk EVs. Nine differently expressed known miRNAs were detected in responding to different feed formulations. Cow milk EVs are abundant of small RNAs, especially miRNAs, which might be closely related to the development of maternal mammary gland and neonatal immune maturity.
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:The severity of negative energy balance (NEB) in high-producing dairy cows has a high incidence among health diseases. The periparturient period is crucial for the health status and reproductive performance of dairy cows. During this period, dairy cows experience a transition from a pregnant, non-lactating state to a non-pregnant, lactating state. At the beginning of lactation, the energy needs for milk production are higher than the available energy consumed from feed intake, resulting in a negative energy balance (NEB)]. While in a NEB, cows mobilise their reserves from adipose tissue, resulting in elevated plasma concentrations of non-esterified fatty acids (NEFAs), which are used as a fuel source by peripheral tissues and the mammary gland for milk fat synthesis. Thus, white adipose tissue is one of the main tissue involved in the energy production during this transition period. So the objectives of our study were to dentify mRNA differentially expressed in white adipose before and after calving in dairy cow fed with low (LE) and high (HE) energy diet.
Project description:Heat stress (HS) has become a major challenge in the dairy industry around the world. Although numerous measures have been taken to alleviate the HS impact on milk production, the cellular level response to HS remains unclear in dairy cows. The objective of this study was to dissect functional alterations based on transcriptomic dynamics in the liver of cows under HS. Dairy cows exposed to HS exhibited both decreased feed intake and milk yield. Through liver transcriptomic analysis, differentially expressed genes were identified among three experimental conditions, including heat stress (HS), pair-fed (PF), and thermoneutral (TN) groups. We observed the upregulation of protein folding and inflammation-related genes in the HS group, while the mitochondrial genes were downregulated. Gene functional enrichment also revealed that mitochondria function and oxidative phosphorylation were dysregulated under HS. The liver transcriptome analysis generated a comprehensive gene expression regulation network upon HS in lactating dairy cows. Overall, this study provides novel insights into molecular and metabolic changes of cows conditioned under HS. Our results could facilitate the development of efficient biomarkers to mitigate the negative effect of HS on dairy cow health and productivity.
Project description:The objective was to study the transcriptomic changes in adipose tissue in the early stages of lactation, specifically in Bos Taurus, Holstein dairy cattle as a function of milk production and genetic merit. Chip quality backgrounds averaged below 50 units, and 3'/5' bias on control genes < 2.0. Correlations among replicates were > 0.85. The design was a simple paired sampling, with time (30 d prepartum and 14 d postpartum as the sampling times. There was no dietary manipulation. Animals were all first calving Holstein heifers, all raised on the same farm on the same diet
Project description:The aim of this study was to determine the effects of linseed dietary supplementation on gene expression in the mammary gland of grazing dairy cows. Milk composition and gene expression in the mammary gland tissue were evaluated in dairy cows supplemented with linseed. The linseed 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. The experiment was carried out in a complete randomized blocked designed structure comprising 14 Holstein-Friesian cows (6 second parity, 2 third parity and 6 older cows), selected from a 550-cow herd. Cows were paired in 7 blocks on the basis of similarity in parity (second parity, third parity and older cows), expected date of calving, and milk performance in the previous lactation (in order of priority). Cows within each block were randomly allocated to one of two treatment groups, “Omega” or “Control”. The dietary Omega treatment consisted of a basal diet supplemented with a concentrate-mixture including linseed on a dry matter (DM) basis, whereas cows in treatment group Control were supplemented with a concentrate mixture without linseed. Linseed was chosen because it is rich in c9,c12,c15-18:3 (ALA). Concentrate mixtures were fed with a concentrate dispenser. Experimental treatments started 3 weeks before the expected calving date (wk -3) and lasted until 6 weeks after calving (wk 6).