Polymorphisms in the GHRL gene and their associations with traits of economic interest in beef cattle

Association of ghrelin gene polymorphisms with slaughter traits in pig

It has been hypothesized that mutations in the ghrelin gene in pigs may play a similar role as in humans and may be associated with obesity. The aim of study was to analyse the polymorphisms of ghrelin gene and to evaluate its effect on pigs’ carcass traits. The effect of c.-93A>G, 4428T>C and g.4486C>T polymorphisms at the ghrelin gene on slaughter performance were analysed in 346 gilts represented by three breeds (Polish Landrace, Duroc, Pietrain). Animals were fattened from 30 to 100 (±2.5) kg body weight. After slaughter, the carcasses were chilled for 24 hours (4ºC), weighted and the right half-carcasses were dissected and evaluated. A number of data were obtained including: meat weight in primary cuts, weight of ham, backfat thickness and carcass yield. From breeding and production point of view, the favourable results were obtained for pigs with the GG genotype at the c.-93A>G locus, characterized by better carcass results than those with the AA genotype, e.g. higher ham weight and lower average backfat thickness. In pigs with the TT genotype at the g.4428T>C locus, we found lower mean backfat thickness than pigs with the CC genotype.

A Gene-Set Enrichment and Protein-Protein Interaction Network-Based GWAS with Regulatory SNPs Identifies Candidate Genes and Pathways Associated with Carcass Traits in Hanwoo Cattle

Non-synonymous SNPs and protein coding SNPs within the promoter region of genes (regulatory SNPs) might have a significant effect on carcass traits. Imputed sequence level data of 10,215 Hanwoo bulls, annotated and filtered to include only regulatory SNPs (450,062 SNPs), were used in a genome-wide association study (GWAS) to identify loci associated with backfat thickness (BFT), carcass weight (CWT), eye muscle area (EMA), and marbling score (MS). A total of 15, 176, and 1 SNPs were found to be significantly associated (p < 1.11 × 10-7) with BFT, CWT, and EMA, respectively. The significant loci were BTA4 (CWT), BTA6 (CWT), BTA14 (CWT and EMA), and BTA19 (BFT). BayesR estimated that 1.1%~1.9% of the SNPs contributed to more than 0.01% of the phenotypic variance. So, the GWAS was complemented by a gene-set enrichment (GSEA) and protein-protein interaction network (PPIN) analysis in identifying the pathways affecting carcass traits. At p < 0.005 (~2,261 SNPs), 25 GO and 18 KEGG categories, including calcium signaling, cell proliferation, and folate biosynthesis, were found to be enriched through GSEA. The PPIN analysis showed enrichment for 81 candidate genes involved in various pathways, including the PI3K-AKT, calcium, and FoxO signaling pathways. Our finding provides insight into the effects of regulatory SNPs on carcass traits.

Association of Ghrelin Gene Polymorphisms with Fattening Traits and Feed Intake in Pig: A Preliminary Study

Simple Summary

From a production point of view, feed intake, growth and carcass quality are among the most important traits in pig breeding. Understanding the mechanisms and processes going on inside the animal’s body can help in the selection of herds and improvement in economic effectiveness. Previous research conducted on different species has showed that ghrelin (GHRL) is responsible for feed intake, efficiency of growth, etc. Thus, evaluation of the regulatory regions and coding sequence of the porcine GHRL gene may be useful as a molecular marker for selected fattening and feed efficiency traits. In this paper, a promising mutation at the locus g.4486C>T was found, which was associated with total feed intake.

Abstract

Numerous studies have been conducted to explain the biological functions and mechanism of ghrelin (GHRL) action in animals. However, the exact role of ghrelin in the regulation of growth and development in pigs is still unclear. The ghrelin gene is considered to be a good candidate marker for the identification of economically important traits in pig production such as feed intake, growth or carcass quality. The objectives of the present study were to investigate the regulatory regions and coding sequence of the porcine GHRL gene and determine the effect of polymorphisms at the ghrelin gene locus on selected fattening traits. Data were obtained from 346 gilts (pure breeds: Landrace, 188; Duroc, 74; Pietrain, 84). The PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) method was used to detect polymorphisms within GHRL. Three polymorphisms were found, one in the promoter region (c.-93A>G) and two in the 3’UTR sequence (g.4428T>C; g.4486C>T). A significant (p ≤ 0.01) additive effect on daily gain (negative) and age at slaughter (positive) was obtained at the locus c.-93A>G. However, the most promising mutation was at the locus g.4486C > T, which is associated with total feed intake. Overall, the described GHRL polymorphisms may be useful as molecular markers in pig selection but future studies are required.

Integrated data mining of transcriptomic and proteomic datasets to predict the secretome of adipose tissue and muscle in ruminants

Adipose tissue and muscle are endocrine organs releasing signalling and mediator proteins termed adipokines and myokines. The identification of the complete set of proteins secreted by adipose tissue and muscle is a challenge to understand the molecular cross-talk between these tissues and to reveal potential targets to control body or muscle composition and metabolism.