Effect of QSOX1 on cattle carcass traits as well as apoptosis and triglyceride production in bovine fetal fibroblasts and mammary epithelial cells

Hepatic transcriptome analysis identifies genes, polymorphisms and pathways involved in the fatty acids metabolism in sheep

Fatty acids (FA) in ruminants, especially unsaturated FA (USFA) have important impact in meat quality, nutritional value, and flavour quality of meat, and on consumer’s health. Identification of the genetic factors controlling the FA composition and metabolism is pivotal to select sheep that produce higher USFA and lower saturated (SFA) for the benefit of sheep industry and consumers. Therefore, this study was aimed to investigate the transcriptome profiling in the liver tissues collected from sheep with divergent USFA content in longissimus muscle using RNA deep-sequencing. From sheep (n = 100) population, liver tissues with higher (n = 3) and lower (n = 3) USFA content were analysed using Illumina HiSeq 2500. The total number of reads produced for each liver sample were ranged from 21.28 to 28.51 million with a median of 23.90 million. Approximately, 198 genes were differentially regulated with significance level of p-adjusted value <0.05. Among them, 100 genes were up-regulated, and 98 were down-regulated (p<0.01, FC>1.5) in the higher USFA group. A large proportion of key genes involved in FA biosynthesis, adipogenesis, fat deposition, and lipid metabolism were identified, such as APOA5, SLC25A30, GFPT1, LEPR, TGFBR2, FABP7, GSTCD, and CYP17A. Pathway analysis revealed that glycosaminoglycan biosynthesis- keratan sulfate, adipokine signaling, galactose metabolism, endocrine and other factors-regulating calcium metabolism, mineral metabolism, and PPAR signaling pathway were playing important regulatory roles in FA metabolism. Importantly, polymorphism and association analyses showed that mutation in APOA5, CFHR5, TGFBR2 and LEPR genes could be potential markers for the FA composition in sheep. These polymorphisms and transcriptome networks controlling the FA variation could be used as genetic markers for FA composition-related traits improvement. However, functional validation is required to confirm the effect of these SNPs in other sheep population in order to incorporate them in the sheep breeding program.

Identification of three new microsatellites and their effects on body measurement traits in pigs using time of flight-mass spectrometry (TOF-MS)

The body status of livestock affects their physiological function and productive performances. Microsatellites, one of the most used DNA markers, have been found to be associated with pig productive traits. However, their identifications and effects on body measurement traits of the Chinese Qinghai Bamei pig still uncovered. According to our previous sequencing data, in this study, three novel microsatellites were found in this breed. Using time of flight-mass spectrometry (TOF-MS) method, these microsatellites were further identified in a large Bamei pig population. TOF-MS spectra showed that there are three microsatellites loci, named P1, P2 and P3. These microsatellites were linkage equilibrium based on the values of D' and r² tests. Association results demonstrated that P1 locus was associated with the body length, body height and chest width and the beneficial genotype was 150-/150-bp (p < 0.05); and P2 locus was associated with the body height (p < 0.05), and the 145-/145-bp, 145-/147-bp and 145-/149-bp were claimed as favorable genotypes and 145-bp allele was considered as the favorable allele. These findings suggested that P1 and P2 microsatellites might be considered as the candidate genetic markers to select pigs with superior body sizes, especially in local breed.

Lipopolysaccharide inhibits triglyceride synthesis in dairy cow mammary epithelial cells by upregulating miR-27a-3p, which targets the PPARG gene

The fat content of milk determines the quality of milk, and triglycerides are the major components of milk fat. Milk fat synthesis is regulated by many factors. Lipopolysaccharide (LPS) has been shown to inhibit milk fat synthesis in bovine mammary epithelial cells, but research on the underlying mechanisms has been limited. MicroRNA (miRNA) are involved in many physiological processes, but there have been few studies on their regulation in milk fat synthesis. In this study, we aimed to investigate whether LPS upregulates miR-27a-3p, which targets PPARG, thereby inhibiting the synthesis of triglycerides in a dairy cow mammary epithelial cell line (MAC-T). After LPS stimulation of MAC-T cells, PPARG gene expression and milk fat synthesis were inhibited. TargetScan software was used to predict miRNA targeting PPARG, and miR-27a-3p was selected as a candidate. A dual luciferase reporter assay further confirmed the targeting connection between miR-27a-3p and the PPARG gene. To investigate the functions of miR-27a-3p, miR-27a-3p mimic and inhibitors were transfected into MAC-T cells. The mRNA and protein levels of PPAR-γ were negatively correlated with the expression of miR-27a-3p. Lipid droplet accumulation and triglyceride synthesis were also negatively correlated with miR-27a-3p expression. Inhibition of miR-27a-3p partially reversed the LPS-induced decreases in PPARG expression and milk fat synthesis. In summary, our results reveal that LPS can inhibit MAC-T cell milk fat synthesis by upregulating miR-27a-3p, which targets the PPARG gene.