Project description:We functionally analyzed the rumen epithelial transcriptomes from low- and high- feed efficient beef steers to identify differences that might contribute to variation in feed efficiency.
Project description:The potential for dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) to improve reproductive efficiency in cattle has received much interest. The mechanisms by which n-3 PUFA may affect physiological and biochemical processes in key reproductive tissues are likely to be mediated by significant alterations in gene expression. We used microarrays to assess endometrial gene expression on day 17 of the estrous cycle in n-3 PUFA compared with control fed heifers. Beef heifers were supplemented with a rumen protected source of either a saturated fatty acid (CON; palmitic acid) or high n-3 PUFA (n-3 PUFA; 275 g) diet per animal per day for 45 days and global gene expression was determined in uterine endometrial tissue using an Affymetrix® oligonucleotide bovine array.
Project description:The selection of cattle with high feed efficiency is of paramount importance with regard to reducing feed costs in the beef industry. Developing predictive biological markers specifically for improved feed efficiency is an attractive alternative to direct measurement on large numbers of animals.Evidence is provided that, effects of RFI on gene expression in muscle of beef cattle are not consistent across breed type or dietary phase. These novel observations challenge the practicality of selecting and breeding for low RFI animals across different diets and stages of development. Perhaps, future research should be directed at utilising different diets to harness the full genetic potential of animal based on breed or stage of maturity. Further to this, evidence is provided from our own work and that of others that less efficient HF steers consuming zero grazed grass are under increased stress as demonstrated by an upregulation of immune function in these animals.
Project description:Beef marbling is caused by intramuscular deposition, and it is an economically important trait in the beef industry. Vitamin A (VA) is an important feed supplement for cattle, but it can hinder marbling if provided in excess. In cattle, VA forms various derivatives such as all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9cRA). Therefore, we investigated the genes involved in bovine intramuscular adipogenesis after VA treatment with ATRA and 9cRA. Differential gene expression levels were validated by microarray analysis in a clonal bovine intramuscular preadipocyte (BIP) cell line derived from the intramuscular adipose tissue of Japanese Black cattle. BIP cells were harvested six days after adipogenic stimulation with either 1 μM ATRA, 1 μM 9cRA, or nonretinoic acids control. The ATRA- and 9cRA-treated cells exhibited reduced transcription of genes involved in the circulatory system and muscle development compared with the no retinoic acid (RA) treatment. In addition, the ATRA- and 9cRA-treated cells exhibited increased transcription of genes involved in the immune system, protein kinase B signaling, and responses to various stimuli. These results demonstrate the lower expression of muscle development in ATRA- and 9cRA-treated BIP cells during adipogenesis.
Project description:Copy number variations (CNVs), which represent a significant source of genetic diversity in mammals, are currently being associated with phenotypes of clinical relevance, mostly in humans and mice. Notwithstanding, little is known about the extent of CNV that contributes to genetic variation in cattle. This study reports the highest resolution map of copy number variation in the cattle genome, with 304 CNV regions (CNVRs) being identified among the genomes of 20 bovine samples from 4 dairy and beef breeds. We used a set of NimbleGen CGH arrays that tile across the assayable portion of the cattle genome with approximately 6.3 million probes, at a 301 bp median probe spacing. These CNVRs covered 0.68% (23 Mb) of the genome, and ranged in size from 1.7 to 2,031 kb (median size 16.7 kb). About 20% of the CNVs colocalized with segmental duplications while 30% encompassed genes, mostly related with environmental response. About 10% of the orthologous CNV cow-human genes are related with human disease susceptibility and, hence, may have important phenotypic consequences. Together, this analysis provides a useful resource to assist with the assessment of CNVs in the contexts of bovine variation, health and productive efficiency.
Project description:We explored the effect of long-term high-concentrate diet feeding on ruminal pH and fermentation, and its effect on the rumen epithelial transcriptomes in Japanese Black beef cattle during a 20-month fattening period.
Project description:Copy number variations (CNVs), which represent a significant source of genetic diversity in mammals, are currently being associated with phenotypes of clinical relevance, mostly in humans and mice. Notwithstanding, little is known about the extent of CNV that contributes to genetic variation in cattle. This study reports the highest resolution map of copy number variation in the cattle genome, with 304 CNV regions (CNVRs) being identified among the genomes of 20 bovine samples from 4 dairy and beef breeds. We used a set of NimbleGen CGH arrays that tile across the assayable portion of the cattle genome with approximately 6.3 million probes, at a 301 bp median probe spacing. These CNVRs covered 0.68% (23 Mb) of the genome, and ranged in size from 1.7 to 2,031 kb (median size 16.7 kb). About 20% of the CNVs colocalized with segmental duplications while 30% encompassed genes, mostly related with environmental response. About 10% of the orthologous CNV cow-human genes are related with human disease susceptibility and, hence, may have important phenotypic consequences. Together, this analysis provides a useful resource to assist with the assessment of CNVs in the contexts of bovine variation, health and productive efficiency. 20 samples were analyzed in a dye-swap loop design. In order to cover the latest bovine genome assembly (bt4) with high density, custom Nimblegen HD2 CGH arrays were planned in 3 designs. Each design covered a specific set of chromosomes with 2.1M probes, which yielded 420 bp of average probe spacing (301 bp median probe spacing).
Project description:Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine. It has been shown to relieve the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis, but the mechanism of CrPyr influencing rumen fermentation remains unclear. This study aimed to use metaproteomics technologies to investigate the bacterial protein function in rumen fluid samples taken from heat-stressed beef cattle treated with or without 60 g/d CrPyr.