Effect of Five Polymorphisms on Percentage of Oleic Acid in Beef and Investigation of Linkage Disequilibrium to Confirm the Locations of Quantitative Trait Loci on BTA19 in Japanese Black Cattle

Five polymorphisms associated with the percentage of oleic acid (C18:1) in beef fat were previously reported on bovine chromosome 19 in different Japanese Black cattle populations. This study aimed to verify the effects of these five polymorphisms on C18:1 using the same Japanese Black cattle population and conduct linkage disequilibrium (LD) analysis in order to determine the locations of the quantitative trait loci (QTLs). We genotyped the five polymorphisms (SREBP1 c.1065 + 83 (84bp indel), STARD3 c.1187 C > T, GH c.379 C > G, FASN g.841 G > C, and FASN g.16024 A > G) in two populations, which were bred in Hyogo and Gifu Prefectures, Japan (n = 441 and 443, respectively) in order to analyze their effects on C18:1 using analysis of variance (ANOVA). In the Hyogo population, SREBP1 c.1065 + 83 and STARD3 c.1187 C > T were significantly associated with C18:1 (p < 0.001). Meanwhile, FASN g.841 G > C, FASN g.16024 A > G, and GH c.379 C > G were significantly associated with C18:1 (p < 0.01) in the Gifu population. LD analysis was subsequently conducted to detect the range of the QTLs, which ranged from 32.2 to 46.4 Mbp and from 47.8 to 52.1 Mbp in the Hyogo and Gifu populations, respectively. In conclusion, this study confirmed the existence of QTLs on BTA19 and divided the candidate region for each QTL based on LD coefficients. These results could contribute to efficient searches for responsible genes and polymorphisms for fatty acid composition.

Single nucleotide polymorphism rs110861313 in the intergenic region of chromosome 23 is associated with the development of leukosis in the Russian Black Pied cattle

In recent years, using a genome-wide association study (GWAS), a number of single nucleotide polymorphisms (SNPs) have been suggested to be associated with susceptibility to leukemia in cattle. However, all studies have been done with purebred Holstein cows and their hybrids. In this regard, it is important to confirm the functional role of polymorphisms previously identified in a GWAS study in Russian cattle breeds. The aim of this study was to verify the association between rs110861313 in the intergenic region of bovine chromosome 23 and leukemia in the Russian Black Pied cattle. Based on the levels of bovine leukemia virus (BLV)-specific antibodies detected in serum using serodiagnostic techniques, animals were divided into three groups: healthy animals (n = 115), asymptomatic virus carriers (n = 145) and animals with leukemia (n = 107). Genotyping of rs110861313 was carried out using polymerase chain reaction followed by analysis of restriction fragment length polymorphisms. A significant decrease in the frequency of the A/A genotype (11.2 %) was revealed in animals with persistent lymphocytosis compared to virus carriers (27.6 %) (p < 0.002). At the same time, the frequency of animals with the C/C genotype in animals with persistent lymphocytosis (41.1 %) was significantly higher than that of virus carriers (21.4 %) (p < 0.001). In this case, asymptomatic virus carriers can be considered a more suitable control than healthy animals that have not been in contact with the virus. According to bioinformatics analysis, resistance to BLV can be due to the presence of the transcription factor FOXM1 binding site in the region of rs110861313. FOXM1 is expressed in immune cells and can potentially affect the expression of the neighboring genes (LY6G5B, GPANK1, ABHD16A, LY6G6F, LY6G6E, CSNK2B, ApoM). Thus, we found that SNP rs110861313 in the intergenic region of bovine chromosome 23 is associated with the development of leukemia following BLV infection in the Russian Black Pied cattle.

Identification of an immune modulation locus utilising a bovine mammary gland infection challenge model

Inflammation of the mammary gland following bacterial infection, commonly known as mastitis, affects all mammalian species. Although the aetiology and epidemiology of mastitis in the dairy cow are well described, the genetic factors mediating resistance to mammary gland infection are not well known, due in part to the difficulty in obtaining robust phenotypic information from sufficiently large numbers of individuals. To address this problem, an experimental mammary gland infection experiment was undertaken, using a Friesian-Jersey cross breed F2herd. A total of 604 animals received an intramammary infusion ofStreptococcus uberisin one gland, and the clinical response over 13 milkings was used for linkage mapping and genome-wide association analysis. A quantitative trait locus (QTL) was detected on bovine chromosome 11 for clinical mastitis status using micro-satellite and Affymetrix 10 K SNP markers, and then exome and genome sequence data used from the six F1sires of the experimental animals to examine this region in more detail. A total of 485 sequence variants were typed in the QTL interval, and association mapping using these and an additional 37 986 genome-wide markers from the Illumina SNP50 bovine SNP panel revealed association with markers encompassing the interleukin-1 gene cluster locus. This study highlights a region on bovine chromosome 11, consistent with earlier studies, as conferring resistance to experimentally induced mammary gland infection, and newly prioritises theIL1gene cluster for further analysis in genetic resistance to mastitis.

KIRREL is differentially expressed in adipose tissue from ‘fertil+’ and ‘fertil−’ cows: in vitro role in ovary?

We have previously shown that dairy cows carrying the ‘fertil−’ haplotype for one quantitative trait locus affecting female fertility located on the bovine chromosome three (QTL-F-Fert-BTA3) have a significantly lower conception rate and body weight after calving than cows carrying the ‘fertil+’ haplotype. Here, we compared by Tiling Array the expression of genes included in the QTL-F-Fert-BTA3 in ‘fertil+’ and ‘fertil−’ adipose tissue one week after calving when plasma non-esterified fatty acid concentrations were greater in ‘fertil−’ animals. We observed that thirty-one genes were overexpressed whereas twelve were under-expressed in ‘fertil+’ as compared to ‘fertil−’ cows (P < 0.05). By quantitative PCR and immunoblot we confirmed that adipose tissue KIRREL mRNA and protein were significantly greater expressed in ‘fertil+’ than in ‘fertil−’. KIRREL mRNA is abundant in bovine kidney, adipose tissue, pituitary, and ovary and detectable in hypothalamus and mammary gland. Its expression (mRNA and protein) is greater in kidney of ‘fertil+’ than ‘fertil−’ cows (P < 0.05). KIRREL (mRNA and protein) is also present in the different ovarian cells with a greater expression in granulosa cells of ‘fertil+’ than ‘fertil−’ cows. In cultured granulosa cells, recombinant KIRREL halved steroid secretion in basal state (P < 0.05). It also decreased cell proliferation (P < 0.05) and in vitro oocyte maturation (P < 0.05). These results were associated to a rapid increase in MAPK1/3 and MAPK14 phosphorylation in granulosa cells and to a decrease in MAPK1/3 phosphorylation in oocyte. Thus, KIRREL could be a potential metabolic messenger linking body composition and fertility.