Deciphering the mammary gland transcriptome during the dry period in dairy cows under heat stress
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ABSTRACT: The bovine dry period is a dynamic non-lactating phase where the mammary gland undergoes extensive tissue remodeling. Utilizing RNA Sequencing, this study characterized novel genes and pathways involved in this process and determined the impact of dry period heat stress. Mammary tissues were collected before and during the dry period (-3, 3, 7, 14, and 25 days relative to dry-off) from twelve heat-stressed (HT, n=6) or cooled (CL, n=6) pregnant Holstein cows.
Project description:We investigated alterations in the mammary proteome and phosphoproteome during lactation as a result of dry period heat stress using an isobaric tag for relative and absolute quantitation (iTRAQ)-based approach. Cows were cooled (CL; n = 12) with fans and water soakers in a free stall setting or were heat stressed through lack of access to cooling devices (HT; n = 12) during the entire dry period (approximately 46 days). All cows were cooled postpartum. Mammary biopsies were harvested from a subset of cows at 14, 42, and 84 days in milk.
Project description:We investigated alterations in the mammary proteome and phosphoproteome during lactation as a result of dry period heat stress using an isobaric tag for relative and absolute quantitation (iTRAQ)-based approach. Cows were cooled (CL; n = 12) with fans and water soakers in a free stall setting or were heat stressed through lack of access to cooling devices (HT; n = 12) during the entire dry period (approximately 46 days). All cows were cooled postpartum. Mammary biopsies were harvested from a subset of cows at 14, 42, and 84 days in milk.
Project description:While dietary phosphorus (P) deprivation extending from the dry period into early lactation impairs health and productivity of cows, restricting dietary P supply during the dry period not only appears to be innocuous but rather effectively mitigates hypocalcemia during the first wk of lactation. To investigate possible negative metabolic effects of P deprivation during the dry period, the present study tested the hypothesis that restarted dietary P supply during the dry period alters the liver transcriptome of dairy cows during the periparturient period. Thirty late-pregnant multiparous Holstein-Friesian dairy cows entering their 2nd, 3rd or 4th lactation were assigned to either a dry cow ration with low (LP, 0.16% P in DM) or adequate P content (AP, 0.35% in DM) during the last 4 wk of the dry period (n = 15/group). Liver transcriptomics, which was carried out in a subset of five 2nd parity cows of each group (n = 5), and determination of selected hormones and metabolites in blood of all cows, was performed approximately one wk before calving and on d 3 postpartum. Liver tissue specimens and blood samples were obtained by a micro-invasive biopsy technique from the right 10th intercostal space and puncture of a jugular vein, respectively. 175 hepatic transcripts were expressed differentially between LP vs. AP cows in late pregnancy, and 165 transcripts differed between LP vs. AP cows in early lactation (Fold change > 1.3 and < -1.3, P < 0.05). In late pregnancy, the enriched biological processes of the up-regulated and the down-regulated transcripts were mainly related to immune processes and signal transduction (P < 0.05), respectively. In early lactation, the enriched biological processes of the up-regulated and the down-regulated transcripts were involved in mineral transport and biotransformation (P < 0.05), respectively. The plasma concentrations of the hormones and acute phase proteins (progesterone, insulin-like growth factor 1, serum amyloid alpha, haptoglobin, and 17β-estradiol) determined were not affected by P supply. These results suggest that P deprivation during the dry period moderately affects the liver transcriptome of cows in late pregnancy and early lactation, and causes no effects on important plasma hormones and acute phase proteins indicating no obvious impairment of health or metabolism of the cows.
Project description:The dry period in cow are critical to mammary health and the success of the next lactation. The expression of proteins the dry period progresses need to be characterized to provide information on involution and immune functions during the dry period. Total protein and lactoferrin concentrations rose significantly by days 10 and 21 after cessation of lactation. Using the day 21 dry secretions we examined their ability to inhibit bacterial growth. Bacterial growth inhibition was not correlated with lactoferrin for 4 coliforms tested nor for all 7 mastitis pathogens. Label free mass spectroscopy was used to quantify changes in whey proteins from milk/dry secretions collected on days 0, 3,10, and 21 of the dry period. 776 proteins were identified. 109 proteins were upregulated at one or more times in the dry period. The most significate enriched GO functional terms for the up-regulated proteins were immune function and stress related. 68 proteins were down regulated in the dry period. The most significant enriched GO functional terms for the down-regulated proteins were stress and immune function related. 12 proteins were significantly correlated with coliform growth. The dry secretion composition changes we found provide information for understanding the dry period. The sample code for the MS raw files is as follows. The 3 technical replicates are denoted as a letter A, B and C. The number following is the cow identification number for 11 cows used. The final two-digit number after the underscore is the day sampled where _01 = day 1, _03 = day 3, _10 = day 10 and _21 = day 21 of dry period. For example, A1313_01 is technical replicate A for cow 1313 collected on day 1. B1313_03 is technical replicate B for cow 1313 collected on day 3.
Project description:In this study, two small RNA libraries were constructed using dry period and peak lactation dairy goat mammary gland tissues and sequenced by the Illumina Solexa high-throughput sequencing system. A total of 346 conserved and 95 novel miRNAs were identified in the dairy goat. The expression of miRNAs was confirmed by qRT-PCR in nine tissues and the mammary gland during development cycles. In addition, several candidate miRNAs that may be involved in mammary gland development and lactation were found by the comparison of miRNA expression profiles among different tissue and developmental stages of the mammary gland. This study provides the identification and profile of miRNAs related to the biology of the mammary gland in the dairy goat. The identification of these miRNAs could contribute to understanding the molecular mechanisms of lactation physiology and the development of the mammary gland in the dairy goat.
Project description:In dairy cows, the transition from dry and pregnant to non-pregnant and lactating creates metabolic and immunological strain, which means many cows succumb to metabolic and infectious disease. This peripartum period, from three weeks pre-calving to three-weeks post-calving, is also known at the transition period. Metabolic health status during the transition period is determined by plasma concentrations of non-esterified fatty acids (NEFA), plasma β-hydroxybutyrate (BHBA), and liver triacylglycerol (TAG). High concentrations of these indicate cows that are under metabolic stress during the transition period and are, therefore, more likely to experience health conditions, also known as transition failure. Neutrophils, phagocytic cells of the innate immune response, are fundamental for fighting infectious agents.
Project description:Our overall objective is to identify key differences in gene expression signaling pathways in the epithelial and intralobular stromal compartments during prepartum mammary remodeling and development in the dry cow.
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).
Project description:The aim of the study was to identify genes which are differentially expressed in the peripheral blood nuclear cells of two breeds of cattle (Holstein-Friesian and Polish Red) and cervine in different points in their physiological states (dry-off period, peak of lactation) RNA from peripheral blood nuclear cells taken from cattle and cervine in peak lactation and dry period were hybridized to Agilent two color microarrays with a common reference. There were four Holstein-Friesian cattle, four Polish Red cattle and four deer investigated. The whole blood was drawn in two time point from each animal – during dry period and peak lactation. This means that there were six research groups (Holstein-Friesian cattle in dry period and Holstein-Friesian cattle in peak lactation; Polish Red cattle in dry period and Polish Red cattle in peak lactation; Deer in dry period and Deer in peak lactation). Using Gene Spring Software (one-way ANOVA and Tukey's HSD Post-hoc test) three lists of differentially expressed transcripts were obtained: a list of 576 transcripts which differ deer in dry period and in peak lactation, a list of 437 transcripts which differ Holstein-Friesian cattle in dry period and in peak lactation and a list of 158 transcripts which differ Polish Red cattle in dry period and in peak lactation.