BackgroundMeat quality depends on physiological processes taking place in muscle tissue, which could involve a large pattern of genes associated with both muscle structural and metabolic features. Understanding the biological phenomena underlying muscle phenotype at slaughter is necessary to uncover meat quality development. Therefore, a muscle transcriptome analysis was undertaken to compare gene expression profiles between two highly contrasted pig breeds, Large White (LW) and Basque (B), reared in two different housing systems themselves influencing meat quality. LW is the most predominant breed used in pig industry, which exhibits standard meat quality attributes. B is an indigenous breed with low lean meat and high fat contents, high meat quality characteristics, and is genetically distant from other European pig breeds.Methodology/Principal FindingsTranscriptome analysis undertaken using a custom 15 K microarray, highlighted 1233 genes differentially expressed between breeds (multiple-test adjusted P-value<0.05), out of which 635 were highly expressed in the B and 598 highly expressed in the LW pigs. No difference in gene expression was found between housing systems. Besides, expression level of 12 differentially expressed genes quantified by real-time RT-PCR validated microarray data. Functional annotation clustering emphasized four main clusters associated to transcriptome breed differences: metabolic processes, skeletal muscle structure and organization, extracellular matrix, lysosome, and proteolysis, thereby highlighting many genes involved in muscle physiology and meat quality development.Conclusions/SignificanceAltogether, these results will contribute to a better understanding of muscle physiology and of the biological and molecular processes underlying meat quality. Besides, this study is a first step towards the identification of molecular markers of pork quality and the subsequent development of control tools.

MYOG and MYF6 belong to the MyoD gene family. They code for the bHLH transcription factors playing a key role in later stages of myogenesis: differentiation and maturation of myotubes. Three SNPs in porcine MYF6 and two in porcine MYOG were analysed in order to establish associations with chosen carcass quality and growth rate traits in Polish Landrace, Polish Large White and line 990 sows. No statistically significant effect of SNP in the promoter region of the MYF6 gene on its expression measured on mRNA level was found. Associations between the genotype at the MYF6 locus and carcass quality traits appeared to be breed-dependent. The C allele in the case of SNP in the promoter region and GC haplotype in exon 1 were advantageous for right carcass side weight in Polish Landrace sows and disadvantageous for this trait in Polish Large White sows. These gene variants were also the most advantageous for loin and ham weight in sows of line 990. The mutation in exon 1 of the MYOG gene had no statistically significant association with carcass quality traits and the mutation in the 3'-flanking region had the breed-dependent effect as well. These results suggest that SNPs analysed in this study are not causative mutations, but can be considered as markers of some other, still unrevealed genetic polymorphism that influences the physiological processes and phenotypic traits considered in this study.

Subfertility has negative effects for dairy farm profitability, animal welfare and sustainability of animal production. Increasing herd sizes and economic pressures restrict the amount of time that farmers can spend on counteractive management. Genetic improvement will become increasingly important to restore reproductive performance. Complementary to traditional breeding value estimation procedures, genomic selection based on genome-wide information will become more widely applied. Functional genomics, including transcriptomics (gene expression profiling), produces the information to understand the consequences of selection as it helps to unravel physiological mechanisms underlying female fertility traits. Insight into the latter is needed to develop new effective management strategies to combat subfertility. Here, the importance of functional genomics for dairy cow reproduction so far and in the near future is evaluated. Recent gene profiling studies in the field of dairy cow fertility are reviewed and new data are presented on genes that are expressed in the brains of dairy cows and that are involved in dairy cow oestrus (behaviour). Fast-developing new research areas in the field of functional genomics, such as epigenetics, RNA interference, variable copy numbers and nutrigenomics, are discussed including their promising future value for dairy cow fertility.

The aim of the study was to evaluate the relations between genotype effects at porcine loci MYF3, MYF4, MYF5 and MYF6 on meat quality traits in pigs of the CC genotype at the RYR1 locus. Meat traits were analysed in longissimus lumborum muscle in 98 pigs (75 of PLW´PL and 25 [PLW´PL]´Pietrain crosses). The determined meat characteristics covered the pH 1 and pH u records, visual assessment of colour and exudation on fresh meat samples, water holding capacity, drip loss, spectrophotometric measurements of dominant wavelength, colour saturation and lightness, L, a*, b* values according to the CIE system, basic chemical constituents (water, protein, intramuscular fat and ash) and soluble protein fraction in meat. The distribution of animals within particular MyoD genotypes only in the MYF4 and MYF5 genotypes were spread uniformly. The gene effects at particular MyoD loci on studied meat traits were significant. The most pronounced effect on meat quality was exerted by the myogenin gene (MYF4). Individuals of the BB genotype in respect to the MYF4 locus showed a better water holding capacity (P<0.01), lower drip loss (P<0.05), darker colour score (P<0.01) and better wateriness score (P<0.01), darker and more desirable colour characteristic (P<0.01) than pigs with the AA genotype, whereas AB genotype animals had intermediate values. In respect to meat protein solubility the AA genotype pigs had a significantly lower level of soluble protein in meat than AB and BB (P<0.01). On basis of the present study it may be inferred that mutations in coding and the non-coding regions of MyoD genes exert significant effects on muscle traits related to oxidative metabolism, as well as related to glycolysis and contractile muscle properties, and thereby on meat quality.