Maternal undernutrition during periconceptional period affects whole-genome ovine muscle methylation in adult offspring.

Experimental and epidemiological studies suggest that maternal nutritional status during early pregnancy, including the period around the time of conception, may induce long-lasting epigenetic changes in the offspring. However, this remains largely unexplored in livestock. Therefore, the objective of this study was to evaluate if modification of the maternal diet of sheep (CTR: control; UND: 50% undernutrition) during the periconceptional period (42 d in total: -14/+28 from mating), would impact CpG methylation in muscle tissue (Longissimus dorsi) of adult offspring (11.5 mo old). Reduced representation bisulfite sequencing identified 262 (Edge-R, FDR < 0.05) and 686 (logistic regression, FDR < 0.001) differentially methylated regions (DMRs) between the UND and CTR groups. Gene ontology analysis identified genes related to development, functions of the muscular system, and steroid hormone receptor activity within the DMRs. The data reported here show that nutritional stress during early pregnancy leads to epigenetic modifications in the muscle of the resulting offspring, with possible implications for cardiac dysfunction, muscle physiology, and meat production.

The formation of the epigenetic pattern of an organism is highly sensitive to environmental factors, especially during early mammalian development, when epigenetic reprogramming of the whole genome takes place. In utero adverse conditions experienced during early pregnancy, such as maternal undernutrition, may induce long-lasting epigenetic changes in the resulting offspring. This study investigated the CpG methylation variations in muscle tissue of adult offspring induced by differences in the diet of their mothers during pregnancy. Our data show that undernutrition during pregnancy leads to epigenetic alterations in the muscle of the offspring, with a potential impact on animal health and productivity.

The Quest for Genes Involved in Adaptation to Climate Change in Ruminant Livestock.

Livestock radiated out from domestication centres to most regions of the world, gradually adapting to diverse environments, from very hot to sub-zero temperatures and from wet and humid conditions to deserts. The climate is changing; generally global temperature is increasing, although there are also more extreme cold periods, storms, and higher solar radiation. These changes impact livestock welfare and productivity. This review describes advances in the methodology for studying livestock genomes and the impact of the environment on animal production, giving examples of discoveries made. Sequencing livestock genomes has facilitated genome-wide association studies to localize genes controlling many traits, and population genetics has identified genomic regions under selection or introgressed from one breed into another to improve production or facilitate adaptation. Landscape genomics, which combines global positioning and genomics, has identified genomic features that enable animals to adapt to local environments. Combining the advances in genomics and methods for predicting changes in climate is generating an explosion of data which calls for innovations in the way big data sets are treated. Artificial intelligence and machine learning are now being used to study the interactions between the genome and the environment to identify historic effects on the genome and to model future scenarios.

Genetic Regulation of Biomarkers as Stress Proxies in Dairy Cows.

Stress in livestock reduces productivity and is a welfare concern. At a physiological level, stress is associated with the activation of inflammatory responses and increased levels of harmful reactive oxygen species. Biomarkers that are indicative of stress could facilitate the identification of more stress-resilient animals. We examined twenty-one metabolic, immune response, and liver function biomarkers that have been associated with stress in 416 Italian Simmental and 436 Italian Holstein cows which were genotyped for 150K SNPs. Single-SNP and haplotype-based genome-wide association studies were carried out to assess whether the variation in the levels in these biomarkers is under genetic control and to identify the genomic loci involved. Significant associations were found for the plasma levels of ceruloplasmin (Bos taurus chromosome 1-BTA1), paraoxonase (BTA4) and γ-glutamyl transferase (BTA17) in the individual breed analysis that coincided with the position of the genes coding for these proteins, suggesting that their expression is under cis-regulation. A meta-analysis of both breeds identified additional significant associations with paraoxonase on BTA 16 and 26. Finding genetic associations with variations in the levels of these biomarkers suggests that the selection for high or low levels of expression could be achieved rapidly. Whether the level of expression of the biomarkers correlates with the response to stressful situations has yet to be determined.

Muscle-related traits in cattle: The role of the myostatin gene in the South Devon breed.

In this paper, we examined the effects of an 11-bp mutation within the GDF-8 gene, originally identified in Belgian Blue cattle, in the South Devon breed. The mutation was found at moderate frequency (0.37) in the South Devon population. We quantified the effects of this mutation on growth, body composition and calving traits in South Devon cattle. We found that the mutation significantly increased muscle score and calving difficulty and decreased fat depth. The mutation did not significantly affect weight at 200 and 400 days or muscle depth. Its effect on muscle score and fat depth was additive while its effect on calving difficulty was recessive. The mutation accounted for a significant proportion of the phenotypic variance in muscle score and calving difficulty. There was an economic benefit of the mutation for this data set, however, calculations were sensitive to changes in the parameter values. Additional data would be required to refine these calculations.