MicroRNAs in bovine adipogenesis: genomic context, expression and function.

BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value. This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points. Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. RESULTS: A total of 224 miRNAs were detected of which 155 were expressed in all steers (n = 8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p < 0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p < 0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were confirmed to have coordinated expression with their host genes, transcriptional factor SREBF2 and EP300 (a transcriptional co-activator of transcriptional factor C/EBPα), respectively which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of bovine lipid metabolism/adipogenesis. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. CONCLUSIONS: These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic location, organization and conservation.

Elucidation of molecular mechanisms of physiological variations between bovine subcutaneous and visceral fat depots under different nutritional regimes.

Adipose tissue plays a critical role in energy homeostasis and metabolism. There is sparse understanding of the molecular regulation at the protein level of bovine adipose tissues, especially within different fat depots under different nutritional regimes. The objective of this study was to analyze the differences in protein expression between bovine subcutaneous and visceral fat depots in steers fed different diets and to identify the potential regulatory molecular mechanisms of protein expression. Subcutaneous and visceral fat tissues were collected from 16 British-continental steers (15.5 month old) fed a high-fat diet (7.1% fat, n=8) or a control diet (2.7% fat, n=8). Protein expression was profiled using label free quantification LC-MS/MS and expression of selected transcripts was evaluated using qRT-PCR. A total of 682 proteins were characterized and quantified with fat depot having more impact on protein expression, altering the level of 51.0% of the detected proteins, whereas diet affected only 5.3%. Functional analysis revealed that energy production and lipid metabolism were among the main functions associated with differentially expressed proteins between fat depots, with visceral fat being more metabolically active than subcutaneous fat as proteins associated with lipid and energy metabolism were upregulated. The expression of several proteins was significantly correlated to subcutaneous fat thickness and adipocyte size, indicating their potential as adiposity markers. A poor correlation (r=0.245) was observed between mRNA and protein levels for 9 genes, indicating that many proteins may be subjected to post-transcriptional regulation. A total of 8 miRNAs were predicted to regulate more than 20% of lipid metabolism proteins differentially expressed between fat depots, suggesting that miRNAs play a role in adipose tissue regulation. Our results show that proteomic changes support the distinct metabolic and physiological characteristics observed between subcutaneous and visceral adipose tissue depots in cattle.

Adipogenic transcriptome profiling using high throughput technologies.

The recent technological innovations in the area of functional genomics, gene expression/transcriptomic profiling can provide new insights to understand the molecular basis of adipogenesis. The focus of this review is to highlight the recent advances in our understanding of the complex interplay of gene expression events and the regulatory mechanisms of adipogenesis in mouse cell lines, humans and farm animals. All these studies have employed the availability of constantly evolving high throughput 'omics' technologies including microarrays, RNA-Seq, chromatin immunoprecipitation, next generation sequencing, RNAi, miRNA profiling and quantitative PCR arrays.

Altered microRNA expression in bovine subcutaneous and visceral adipose tissues from cattle under different diet.

BACKGROUND: MicroRNAs (miRNAs) are a class of molecular regulators found to participate in numerous biological processes, including adipogenesis in mammals. This study aimed to evaluate the differences of miRNA expression between bovine subcutaneous (backfat) and visceral fat depots (perirenal fat) and the dietary effect on miRNA expression in these fat tissues. METHODOLOGY/PRINCIPAL FINDINGS: Fat tissues were collected from 16 Hereford×Aberdeen Angus cross bred steers (15.5 month old) fed a high-fat diet (5.85% fat, n = 8) or control diet (1.95% fat, n = 8). Total RNA from each animal was subjected to miRNA microarray analysis using a customized Agilent miRNA microarray containing 672 bovine miRNA probes. Expression of miRNAs was not equal between fat depots as well as diets: 207 miRNAs were detected in both fat depots, while 37 of these were found to be tissue specific; and 169 miRNAs were commonly expressed under two diets while 75 were diet specific. The number of miRNAs detected per animal fed the high fat diet was higher than those fed control diet (p = 0.037 in subcutaneous fat and p = 0.002 visceral fat). Further qRT-PCR analysis confirmed that the expression of some miRNAs was highly influenced by diet (miR-19a, -92a, -92b, -101, -103, -106, -142-5p, and 296) or fat depot (miR-196a and -2454). CONCLUSIONS/SIGNIFICANCE: Our results revealed that the miRNA may differ among adipose depots and level of fat in the diet, suggesting that miRNAs may play a role in the regulation of bovine adipogenesis.

Níveis de anticorpos contra a doença de Newcastle mediante a imunização com vacinas associadas com os vírus da bronquite infecciosa e da infecção da bursa de Fabrícius / Levels of antibodies against Newcastle disease by immunization wuith associated vaccines with infectious bronchitis virus and infectiuos bursal disease

Um artifício atualmente bastante difundido para a imunização de aves em apenas uma única administração, seria a utilização de vacinas associadas; mas segundo alguns pesquisadores, frangos de corte vacinados com vacinas associadas contendo vírus vivos atenuados da doença de Newcastle (DNC) e da bronquite infecciosa das galinhas (BIG), podem sofrer um fenômeno denominado interferência viral, incapacitando o sistema imunológico de estimular a produção de anticorpos (AC) protetores, produzindo uma competição por epítopos, ou dirigindo a resposta imune em outros sentidos. Estes animais foram divididos em nove tratamentos e imunizados com vacinas contendo as cepas HB1 (HB1 e Clone 30) do vírus da DNC e da cepa Massachusetts (H120 e Ma5) para o vírus da BIG, em diversas combinações, administradas pela via ocular. Um tratamento (T11) deixado sem imunização foi utilizado como controle. Os tratamentos T2, T4 e T10 sofreram imunização apenas contra a DNC em separado ou associada no momento da vacinação ou em laboratório à BIG, sendo que nos tratamentos T5, T6, T7, T8 e T9 foi incluída a vacinação contra a infecção da bursa de fabrícius (IBF). Os resultados mostram haver uma redução na produção de AC contra a DNC quando esta foi associada à BIG (tratamento 4), ambas doluídas no mesmo frasco no momento da vacinação. Porém observou-se menor interferência, a partir da utilização de uma vacina já associada em laboratório (tratamento 10). Quanto à presença do vírus da IBF presente nos grupos G5 a G8, este parece favorecer o sistema imune através de um estímulo precoce deste, reduzindo a diferença na qualidade de AC quando estas são posteriormente associadas.

Indução a muda forçada em Galinhas D’Angola (Numida meleagris) através do óxido de zinco / Induced molt in Guinea fowls (Numida meleagris) through the use of zinc oxide

Devido à escassez de estudos sobre muda forçada em aves alternativas de produção, este experimento teve o objetivo de realizar a muda forçada em galinhas D’Angola avaliando as perdas de peso corpóreo (PPC) que promovessem os melhores índices produtivos pós-muda. Com este propósito foram utilizadas 110 galinhas D’angola alojadas individualmente em gaiolas de poedeiras comerciais e, posteriormente, submetidas à muda forçada com 20000 ppm de óxido de zinco na ração. Estas passaram 21 dias recebendo ração e água ad libitum. Para análise da PPC relacionada à produtividade pós-muda foram utilizados 60 aves organizadas nos seguintes grupos: 24% (n=18); 26% (n=18); 28% (n=12) e acima de 30% (n=12). As outras 50 aves foram sacrificadas para o estudo do aparelho reprodutor, onde se verificou o tamanho e peso do oviduto e peso do ovário com PPC de 0% e sua regressão à medida que atingiam os níveis de PPC: 24%; 26%; 28% e acima de 30%. A média de retorno produtivo foi 60%, sendo o grupo com PPC de 24% com o melhor índice (100%), no entanto, este apresentou índice de produção insatisfatório juntamente com o grupo de PPC acima de 30%. A muda forçada em Galinhas D’Angola foi viável com índices de PPC em torno de 26% a 28% e inviáveis com níveis abaixo de 24% e acima de 30%. Em relação à regressão do aparelho reprodutor, os melhores resultados produtivos foram em torno de 65,15%, 90,49% e 94,27% para tamanho e peso do oviduto e peso do ovário, respectivamente.

Due to scarcity of studies on forced molt in alternative production birds, this experiment had the objective of performing an induced molt in Guinea Fowls observing the best body weight losses (BWL) that could promote good post-molt productions. With this purpose, 110 Guinea fowls were housed in individual commercial cages and were submitted to induced molt through the addition of zinc oxide in feed with the concentration of 20000 ppm during 21 days and received drinking water ad libitum. In the analysis of BWL related to post-molt productivity, 60 birds were organized in the groups, according to the percentage of BWL: 24% (n=18), 26% (n=18), 28% (n=12) and more than 30% (n=12). The other 50 birds were sacrificed for analyses of the reproductive organs, in which the oviduct size and weight of oviduct and ovary were measured with 0% of BWL and since then the regression of these organs were calculated to 24%, 26%,28% and more than 30% of BWL. The medium of post-molt return to production was 60% and the group of 24% of BWL presented the best productive return (100%), however this group presented an insufficient production rate as the birds with 30% of BWL. In this way, the induced molt in Guinea fowls was viable with BWL around 26 and 28% and unviable with less than 24% or more than 30%. In relation to regression of the reproductive organs the best productive results were 65,15%,90,49% and 94,27% to oviduct size and weight and ovary weight, respectively.