A gestational high protein diet affects the abundance of muscle transcripts related to cell cycle regulation throughout development in porcine progeny

The Effect of Dietary Protein Imbalance during Pregnancy on the Growth, Metabolism and Circulatory Metabolome of Neonatal and Weaned Juvenile Porcine Offspring

Protein imbalance during pregnancy affects women in underdeveloped and developing countries and is associated with compromised offspring growth and an increased risk of metabolic diseases in later life. We studied in a porcine model the glucose and urea metabolism, and circulatory hormone and metabolite profile of offspring exposed during gestation, to maternal isoenergetic low-high (LP-HC), high-low (HP-LC) or adequate (AP) protein-carbohydrate ratio diets. At birth, LP-HC were lighter and the plasma acetylcarnitine to free carnitine ratios at 1 day of life was lower compared to AP offspring. Plasma urea concentrations were lower in 1 day old LP-HC offspring than HP-LC. In the juvenile period, increased insulin concentrations were observed in LP-HC and HP-LC offspring compared to AP, as was body weight from HP-LC compared to LP-HC. Plasma triglyceride concentrations were lower in 80 than 1 day old HP-LC offspring, and glucagon concentrations lower in 80 than 1 day old AP and HP-LC offspring. Plasma urea and the ratio of glucagon to insulin were lower in all 80 than 1 day old offspring. Aminoacyl-tRNA, arginine and phenylalanine, tyrosine and tryptophan metabolism, histidine and beta-alanine metabolism differed between 1 and 80 day old AP and HP-LC offspring. Maternal protein imbalance throughout pregnancy did not result in significant consequences in offspring metabolism compared to AP, indicating enormous plasticity by the placenta and developing offspring.

TRIENNIAL LACTATION SYMPOSIUM: Nutrigenomics in livestock: Systems biology meets nutrition

The advent of high-throughput technologies to study an animal's genome, proteome, and metabolome (i.e., "omics" tools) constituted a setback to the use of reductionism in livestock research. More recent development of "next-generation sequencing" tools was instrumental in allowing in-depth studies of the microbiome in the rumen and other sections of the gastrointestinal tract. Omics, along with bioinformatics, constitutes the foundation of modern systems biology, a field of study widely used in model organisms (e.g., rodents, yeast, humans) to enhance understanding of the complex biological interactions occurring within cells and tissues at the gene, protein, and metabolite level. Application of systems biology concepts is ideal for the study of interactions between nutrition and physiological state with tissue and cell metabolism and function during key life stages of livestock species, including the transition from pregnancy to lactation, in utero development, or postnatal growth. Modern bioinformatic tools capable of discerning functional outcomes and biologically meaningful networks complement the ever-increasing ability to generate large molecular, microbial, and metabolite data sets. Simultaneous visualization of the complex intertissue adaptations to physiological state and nutrition can now be discerned. Studies to understand the linkages between the microbiome and the absorptive epithelium using the integrative approach are emerging. We present examples of new knowledge generated through the application of functional analyses of transcriptomic, proteomic, and metabolomic data sets encompassing nutritional management of dairy cows, pigs, and poultry. Published work to date underscores that the integrative approach across and within tissues may prove useful for fine-tuning nutritional management of livestock. An important goal during this process is to uncover key molecular players involved in the organismal adaptations to nutrition.

Mechanisms of protein balance in skeletal muscle

Increased global demand for adequate protein nutrition against a backdrop of climate change and concern for animal agriculture sustainability necessitates new and more efficient approaches to livestock growth and production. Anabolic growth is achieved when rates of new synthesis exceed turnover, producing a positive net protein balance. Conversely, deterioration or atrophy of lean mass is a consequence of a net negative protein balance. During early life and periods of growth, muscle mass is driven by increases in protein synthesis at the level of mRNA translation. Throughout life, muscle mass is further influenced by degradative processes such as autophagy and the ubiquitin proteasome pathway. Multiple signal transduction networks guide and coordinate these processes alongside quality control mechanisms to maintain protein homeostasis (proteostasis). Genetics, hormones, and environmental stimuli each influence proteostasis control, altering capacity and/or efficiency of muscle growth. An overview of recent findings and current methods to assess muscle protein balance and proteostasis is presented. Current efforts to identify novel control points have the potential through selective breeding design or development of hormetic strategies to better promote growth and health span during environmental stress.

Dynamic transcriptome profiles of skeletal muscle tissue across 11 developmental stages for both Tongcheng and Yorkshire pigs

Background

The growth and development of skeletal muscle directly impacts the quantity and quality of pork production. Chinese indigenous pig breeds and exotic species vary greatly in terms of muscle production and performance traits. We present transcriptome profiles of 110 skeletal muscle samples from Tongcheng (TC) and Yorkshire (YK) pigs at 11 developmental periods (30, 40, 55, 63, 70, 90, and 105 days of gestation, and 0, 1, 3, and 5 weeks of age) using digital gene expression on Solexa/Illumina’s Genome Analyzer platform to investigate the differences in prenatal and postnatal skeletal muscle between the two breeds.

Results

Muscle morphological changes indicate the importance of primary fiber formation from 30 to 40 dpc (days post coitus), and secondary fiber formation from 55 to 70 dpc. We screened 4,331 differentially expressed genes in TC and 2,259 in YK (log₂ ratio >1 and probability >0.7). Cluster analysis showed different gene expression patterns between TC and YK pigs. The transcripts were annotated in terms of Gene Ontology related to muscle development. We found that the genes CXCL10, EIF2B5, PSMA6, FBXO32, and LOC100622249 played vital roles in the muscle regulatory networks in the TC breed, whereas the genes SGCD, ENG, THBD, AQP4, and BTG2 played dominant roles in the YK breed. These genes showed breed-specific and development-dependent differential expression patterns. Furthermore, 984 genes were identified in myogenesis. A heat map showed that significantly enriched pathways (FDR <0.05) had stage-specific functional regulatory mechanisms. Finally, the differentially expressed genes from our sequencing results were confirmed by real-time quantitative polymerase chain reaction.

Conclusions

This study detected many functional genes and showed differences in the molecular mechanisms of skeletal muscle development between TC and YK pigs. TC pigs showed slower muscle growth and more complicated genetic regulation than YK pigs. Many differentially expressed genes showed breed-specific expression patterns. Our data provide a better understanding of skeletal muscle developmental differences and valuable information for improving pork quality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1580-7) contains supplementary material, which is available to authorized users.

High- and low-protein gestation diets do not provoke common transcriptional responses representing universal target-pathways in muscle and liver of porcine progeny

AIM

Maternal diets introduce transcriptional changes in the offspring, highlighting the concept of genetic and physiological plasticity. Our previous analyses investigated stage-dependent transcriptional responses to either maternal high or low protein/carbohydrate ratios in either muscle or liver. Foetal programming is proposed to be mediated by a small number of gatekeeper processes, such as cytoskeleton remodelling and cell-cycle regulation. Here, we conducted an overall analysis of a three-dimensional data set aiming to elucidate, whether there are universally targeted pathways of adaptive transcriptional response to different protein/carbohydrate ratios.

METHODS

Microarray analyses were performed on liver and skeletal muscle tissue sampled at 94 days post-conception and 1, 28 and 188 days post-natum from offspring (n = 253) of German Landrace gilts that were fed isoenergetic diets containing low, high or adequate protein.

RESULTS

Cluster analyses revealed a hierarchical influence of tissue, ontogenetic stage and diet on transcript levels. Considering results cumulatively over stages, liver showed only marginal transcriptional differences between the dietary groups, whereas considerable differences appeared in muscle. Considering results cumulatively over tissues, nutrition-responsive transcriptions were observed along ontogenesis. Pathway analyses revealed transcript differences in genes related to tissue remodelling, cell-cycle regulation and mitochondrial function.

CONCLUSION

The factors tissue, stage and diet impact gene expression in a hierarchical order. Porcine liver appeared to be a tissue that was more resilient to nutritional modulation compared with skeletal muscle tissue. Differential modulation between tissues and dietary groups reveal that there are no universal target-pathways of adaptive transcriptional response to different protein diets.

Common phenotypes and the developmental origins of disease

PURPOSE OF REVIEW

The association between nutrition during pregnancy and the development of metabolic disease in the offspring has been well evidenced in humans and animals. Whilst evidence has accumulated to support various theories linking maternal diet to long-term health, the precise mechanisms of action remain poorly understood. This review summarizes recent advances within the field, focusing on the use of animal models to investigate common phenotypic outcomes.

RECENT FINDINGS

Continued characterization of postnatal phenotypes has highlighted the importance of postnatal diet in unmasking programming effects of prenatal diet. Whilst common phenotypes are observed across models, differences in associated regulatory processes exist dependent upon the dietary exposure used and sex of the offspring. The use of unbiased techniques at developmental stages has identified gene pathways sensitive to maternal diet, potentially explaining the induction of a common phenotype by different nutritional interventions. Evidence has also grown to support the role of epigenetic modification, with an increasing range of targets identified as being sensitive.

SUMMARY

A challenge remains in identifying the direct functional and long-term consequences of changes in gene expression or epigenetic status during development, and to translate these back to human populations.