Polymorphisms of the Toll-Like Receptor 2 of Goats (Capra hircus) may be Associated with Somatic Cell Count in Milk

DNA polymorphisms and expression profile of immune and antioxidant genes as biomarkers for reproductive disorders tolerance/susceptibility in Baladi goat

The objective of this study was to explore single nucleotide polymorphisms (SNPs) and gene expression of immune and antioxidant markers associated with reproductive disorders in Baladi goats. A total of one hundred adults Baladi does were allocated into two equal-sized groups: normal reproductive performance and does have a history of reproductive disorders. DNA sequencing of PRLR (304-bp), LTF (904-bp), TLR2 (420-bp), TLR4 (335-bp), CLA-DRB3.2 (285-bp), SOD3 (735-bp), CAT (1526-bp), GPX4 (782-bp), and GST (690-bp) revealed SNPs associated with reproductive disorders tolerance/susceptibility in investigated does. Nonetheless, DNA sequencing of beta defensin (483-bp), CCL5 (840-bp), and ATOX1 (374-bp) genes elicited a monomorphic pattern. Levels of PRLR, LTF, TLR2, TLR4, CLA-DRB3.2, beta defensin, and CCL5 genes were significantly up-regulated in does affect with reproductive disorders than tolerant ones; while SOD3, CAT, GPX4, GST and ATOX1 genes pattern elicited an opposite trend. The results herein confirmed the potential significance of SNPs in immune and antioxidant genes as genetic markers for reproductive disorders tolerance/susceptibility in Baladi does. The Gene expression profile of investigated genes could be also used as proxy biomarkers for the prediction of the most susceptible risk time for disease occurrence and for building up an effective management protocol.

DNA Polymorphisms and mRNA Levels of Immune Biomarkers as Candidates for Inflammatory Postpartum Disorders Susceptibility in Italian Buffaloes

The immunological genes that may interact with inflammatory postpartum diseases in Italian buffaloes were examined in this study. A total number of 120 female Italian buffaloes (60 normal and 60 with inflammatory reproductive diseases) were employed. Each buffalo's jugular vein was pierced to get five milliliters of blood. To obtain whole blood and extract DNA and RNA, the blood was placed within tubes containing sodium fluoride or EDTA anticoagulants. The immunological (IKBKG, LGALS, IL1B, CCL2, RANTES, MASP2, HMGB1, and S-LZ) genes' nucleotide sequence differences between healthy buffaloes and buffaloes affected by inflammatory reproductive diseases were found by employing PCR-DNA sequencing. According to Fisher's exact test (p ˂ 0.01), there were noticeably different probabilities of all major nucleotide changes spreading among buffalo groups with and without reproductive problems. Buffaloes were significantly more likely to express the examined genes when they had inflammatory reproductive diseases. The outcomes might support the significance of these markers' nucleotide variations and gene expression patterns as indicators of the prevalence of inflammatory reproductive disorders and provide a workable buffalo management policy.

Candidate genes for mastitis resistance in dairy cattle: a data integration approach

BACKGROUND

Inflammation of the mammary tissue (mastitis) is one of the most detrimental health conditions in dairy ruminants and is considered the most economically important infectious disease of the dairy sector. Improving mastitis resistance is becoming an important goal in dairy ruminant breeding programmes. However, mastitis resistance is a complex trait and identification of mastitis-associated alleles in livestock is difficult. Currently, the only applicable approach to identify candidate loci for complex traits in large farm animals is to combine different information that supports the functionality of the identified genomic regions with respect to a complex trait.

METHODS

To identify the most promising candidate loci for mastitis resistance we integrated heterogeneous data from multiple sources and compiled the information into a comprehensive database of mastitis-associated candidate loci. Mastitis-associated candidate genes reported in association, expression, and mouse model studies were collected by searching the relevant literature and databases. The collected data were integrated into a single database, screened for overlaps, and used for gene set enrichment analysis.

RESULTS

The database contains candidate genes from association and expression studies and relevant transgenic mouse models. The 2448 collected candidate loci are evenly distributed across bovine chromosomes. Data integration and analysis revealed overlaps between different studies and/or with mastitis-associated QTL, revealing promising candidate genes for mastitis resistance.

CONCLUSION

Mastitis resistance is a complex trait influenced by numerous alleles. Based on the number of independent studies, we were able to prioritise candidate genes and propose a list of the 22 most promising. To our knowledge this is the most comprehensive database of mastitis associated candidate genes and could be helpful in selecting genes for functional validation studies.

Cell-Specific Expression Pattern of Toll-Like Receptors and Their Roles in Animal Reproduction

Toll-like receptors (TLRs), a part of the innate immune system, have critical roles in protection against infections and involve in basic pathology and physiology. Secreted molecules from the body or pathogens could be a ligand for induction of the TLR system. There are many immune and non-immune types of cells that express at a least single TLR on their surface or cytoplasm. Those cells may be a player in a defense system or in the physiological regulation mechanisms. Reproductive tract and organs contain different types of cells that have essential functions such as hormone production, providing an environment for embryo/fetus, germ cell production, etc. Although lower parts of reproductive organs are in a relationship with outsider contaminants (bacteria, viruses, etc.), upper parts should be sterile to provide a healthy pregnancy and germ cell production. In those areas, TLRs bear controller or regulator roles. In this chapter, we will provide current information about physiological functions of TLR in the cells of the reproductive organs and tract, and especially about their roles in follicle selection, maturation, follicular atresia, ovulation, corpus luteum (CL) formation and regression, establishment and maintenance of pregnancy, sperm production, maturation, capacitation as well as the relationship between TLR polymorphism and reproduction in domestic animals. We will also discuss pathogen-associated molecular patterns (PAMPs)-induced TLRs that involve in reproductive inflammation/pathology.

Genome-wide association studies of lactation yields of milk, fat, protein and somatic cell score in New Zealand dairy goats

Background

Identifying associations between genetic markers and traits of economic importance will provide practical benefits for the dairy goat industry, enabling genomic prediction of the breeding value of individuals, and facilitating discovery of the underlying genes and mutations. Genome-wide association studies were implemented to detect genetic regions that are significantly associated with effects on lactation yields of milk (MY), fat (FY), protein (PY) and somatic cell score (SCS) in New Zealand dairy goats.

Methods

A total of 4,840 goats were genotyped with the Caprine 50 K SNP chip (Illumina Inc., San Diego, CA). After quality filtering, 3,732 animals and 41,989 SNPs were analysed assuming an additive linear model. Four GWAS models were performed, a single-SNP additive linear model and three multi-SNP BayesC models. For the single-SNP GWAS, SNPs were fitted individually as fixed covariates, while the BayesC models fit all SNPs simultaneously as random effects. A cluster of significant SNPs were used to define a haplotype block whose alleles were fitted as covariates in a Bayesian model. The corresponding diplotypes of the haplotype block were then fit as class variables in another Bayesian model.

Results

Across all four traits, a total of 43 genome-wide significant SNPs were detected from the SNP GWAS. At a genome-wide significance level, the single-SNP analysis identified a cluster of variants on chromosome 19 associated with MY, FY, PY, and another cluster on chromosome 29 associated with SCS. Significant SNPs mapped in introns of candidate genes (45%), in intergenic regions (36%), were 0-5 kb upstream or downstream of the closest gene (14%) or were synonymous substitutions (5%). The most significant genomic window was located on chromosome 19 explaining up to 9.6% of the phenotypic variation for MY, 8.1% for FY, 9.1% for PY and 1% for SCS.

Conclusions

The quantitative trait loci for yield traits on chromosome 19 confirms reported findings in other dairy goat populations. There is benefit to be gained from using these results for genomic selection to improve milk production in New Zealand dairy goats.

TLR2 polymorphism (rs650082970) is associated with somatic cell count in goat milk

Pathogens invading the mammary gland are recognized through a range of pattern recognition receptors (PRRs), residing on the plasma membrane of mammary epithelial cells. Toll-like receptor 2 (TLR2) signalling is responsible for recognition of Gram-positive bacteria, which are the most common mastitis-causing pathogens in goats. Somatic cell counts (SCC) in milk are routinely determined in goat dairy flocks and serve as an indicator of milk quality, which is highly correlated to intramammary infections. Recently, a single nucleotide polymorphism of the TLR2 was suggested to be associated with SCC in goat milk. To further test the suggested association, we genotyped 61 Slovenian Alpine goats included in the dataset. The effect of the genotype was analysed using the general linear model (GLM) procedure of SAS/STAT software. We found the TLR2 genotypes significantly (p = 0.0007) associated with milk SCC. Animals with the A/G genotype had significantly (p ≤ 0.05) lower SCC value in milk compared to the G/G genotype. Our data suggest that the A allele is the minor one and is associated with lower milk SCC. In the current study, we provide a validated PCR-RFLP based genotyping assay for the TLR2 SNP (rs650082970) and confirm its association with milk SCC. Further studies to confirm the association on a larger number of animals of different breeds and to explain functional consequences of the polymorphism in relation to SCC are encouraged.