Myostatin gene inactivation increases post-mortem calpain-dependent muscle proteolysis in mice.

Myostatin deficiency leads to extensive skeletal muscle hypertrophy, but its consequence on post-mortem muscle proteolysis is unknown. Here, we compared muscle myofibrillar protein degradation, and autophagy, ubiquitin-proteasome and Ca-dependent proteolysis relative to the energetic and redox status in wild-type (WT) and myostatin knock-out mice (KO) during early post-mortem storage. KO muscles showed higher degradation of myofibrillar proteins in the first 24 h after death, associated with preserved antioxidant status, compared with WT muscles.

The Blonde d'Aquitaine T3811>G3811 mutation in the myostatin gene: association with growth, carcass, and muscle phenotypes in veal calves.

The mutation T3811 → G3811 (TG3811) discovered in the myostatin gene of the Blonde d'Aquitaine breed is suspected of contributing to the outstanding muscularity of this breed. An experiment was designed to estimate the effect of this mutation in an F2 and back-cross Blonde d'Aquitaine × Holstein population. By genotyping all known mutations in the myostatin gene, it was ensured that the TG3811 mutation was indeed the only known mutation segregating in this population.

Autophagy in farm animals: current knowledge and future challenges.

Autophagy (a process of cellular self-eating) is a conserved cellular degradative process that plays important roles in maintaining homeostasis and preventing nutritional, metabolic, and infection-mediated stresses. Surprisingly, little attention has been paid to the role of this cellular function in species of agronomical interest, and the details of how autophagy functions in the development of phenotypes of agricultural interest remain largely unexplored. Here, we first provide a brief description of the main mechanisms involved in autophagy, then review our current knowledge regarding autophagy in species of agronomical interest, with particular attention to physiological functions supporting livestock animal production, and finally assess the potential of translating the acquired knowledge to improve animal development, growth and health in the context of growing social, economic and environmental challenges for agriculture.

Label free shotgun proteomics for the identification of protein biomarkers for beef tenderness in muscle and plasma of heifers.

Meat quality prediction is a priority for the beef industry. Label free shotgun proteomics was performed on Longissimus muscle and plasma from 20 crossbred Charolais x Aubrac beef heifers, classified as subgroups of 5 extreme tender and 5 extreme tough meat according to sensory evaluation, Warner Bratzler shear force, and a synthetic tenderness index. This technique identified 268 proteins in muscle and 136 in plasma.

Dataset reporting 4654 cow milk proteins listed according to lactation stages and milk fractions.

Milk contains numerous proteins including bioactive molecules that may be important in human nutrition. Thanks to improvements in proteomic methods, hundreds of proteins identified in milk are available through open data from different publications. We gathered these public data to produce an atlas reporting the cow milk proteins.

Aggregation of Omic Data and Secretome Prediction Enable the Discovery of Candidate Plasma Biomarkers for Beef Tenderness.

Beef quality is a complex phenotype that can be evaluated only after animal slaughtering. Previous research has investigated the potential of genetic markers or muscle-derived proteins to assess beef tenderness. Thus, the use of low-invasive biomarkers in living animals is an issue for the beef sector.

Milk proteome from in silico data aggregation allows the identification of putative biomarkers of negative energy balance in dairy cows.

A better knowledge of the bovine milk proteome and its main drivers is a prerequisite for the modulation of bioactive proteins in milk for human nutrition, as well as for the discovery of biomarkers that are useful in husbandry and veterinary medicine. Milk composition is affected by lactation stage and reflects, in part, the energy balance of dairy cows. We aggregated the cow milk proteins reported in 20 recent proteomics publications to produce an atlas of 4654 unique proteins.

Correction: Does growth path influence beef lipid deposition and fatty acid composition?

[This corrects the article DOI: 10.1371/journal.pone.

Does growth path influence beef lipid deposition and fatty acid composition?

Despite the recent advances in transcriptomics, gene expression studies addressing cattle´s skeletal muscle adaptations in response to compensatory growth are warranted, particularly regarding lipid metabolism due to its impact in meat sensory and nutritional traits. In the present study, in comparison to ad libitum feeding, a period of feed restriction was used in order to understand the changes in bull´s lipid metabolism and gene expression of the adipogenic and lipogenic pathways after re-alimentation. Thus, 40 young Alentejana bulls were either fed ad libitum (CG group) from 9 to 18 months of age or subjected to food restriction from 9 to 15 months of age, and fed ad libitum until 24 months of age (DG group).

Exploration of Biological Markers of Feed Efficiency in Young Bulls.

The efficiency with which ruminants convert feed to desirable products is difficult to measure under normal commercial settings. We explored the use of potential biological markers from easily obtainable samples, that is, blood, hair, and feces, to characterize potential causes of divergent efficiency when considered as residual feed intake (RFI) or feed conversion efficiency (FCE). A total of 54 Charolais bulls, 20 in period 1 and 34 in period 2, were examined for individual dry matter intake (DMI) and growth.

Molecular regulation of high muscle mass in developing Blonde d'Aquitaine cattle foetuses.

The Blonde d'Aquitaine (BA) is a French cattle breed with enhanced muscularity, partly attributable to a mutation. The BA has a faster muscle fibre isoform phenotype comprising a higher proportion of fast type IIX fibres compared to age-matched Charolais (CH). To better understand the molecular network of modifications in BA compared to CH muscle, we assayed the transcriptomes of the at 110, 180, 210 and 260 days postconception (dpc).

Calcium Homeostasis and Muscle Energy Metabolism Are Modified in HspB1-Null Mice.

Hsp27-encoded by is a member of the small heat shock proteins (sHsp, 12-43 kDa (kilodalton)) family. This protein is constitutively present in a wide variety of tissues and in many cell lines. The abundance of Hsp27 is highest in skeletal muscle, indicating a crucial role for muscle physiology.

The Invalidation of HspB1 Gene in Mouse Alters the Ultrastructural Phenotype of Muscles.

Even though abundance of Hsp27 is the highest in skeletal muscle, the relationships between the expression of HspB1 (encoding Hsp27) and muscle characteristics are not fully understood. In this study, we have analysed the effect of Hsp27 inactivation on mouse development and phenotype. We generated a mouse strain devoid of Hsp27 protein by homologous recombination of the HspB1 gene.

Expression Marker-Based Strategy to Improve Beef Quality.

For beef cattle research, a main objective is to control concomitantly the development of muscles and the qualities of beef cuts. Beef quality is a complex phenotype that is only detectable after slaughter and is highly variable. The beef industry is in need of tools to estimate beef quality of live cattle or online in abattoirs, with specific attention towards sensory attributes (tenderness, juiciness, flavour, and colour).

Inverse relationships between biomarkers and beef tenderness according to contractile and metabolic properties of the muscle.

Previous proteomic analyses established a list of proteins biomarkers of beef tenderness. The present study quantified the relative abundance of 21 of these proteins by dot-blot technique in the Longissimus thoracis and Semitendinosus muscles of 71 young bulls from three breeds: Aberdeen Angus (AA), Limousin (LI), and Blond d'Aquitaine (BA). For both muscles overall tenderness was estimated by sensory analysis; shear force was measured with a Warner-Bratzler instrument, and an index combining sensory and mechanical measurements was calculated.

A network-based approach for predicting Hsp27 knock-out targets in mouse skeletal muscles.

Thanks to genomics, we have previously identified markers of beef tenderness, and computed a bioinformatic analysis that enabled us to build an interactome in which we found Hsp27 at a crucial node. Here, we have used a network-based approach for understanding the contribution of Hsp27 to tenderness through the prediction of its interactors related to tenderness. We have revealed the direct interactors of Hsp27.

Relationships between muscle growth potential, intramuscular fat content and different indicators of muscle fibre types in young Charolais bulls.

Genetic selection in favor of muscle growth at the expense of fat should affect characteristics of muscles, and therefore beef quality. This study was conducted with two extreme groups of six animals selected among 64 Charolais young bulls ranked according to their genetic potential for muscle growth. Muscle characteristics were assessed in Rectus abdominis (RA, slow oxidative) and Semitendinosus (ST, fast glycolytic) muscles.

The GENOTEND chip: a new tool to analyse gene expression in muscles of beef cattle for beef quality prediction.

Background: Previous research programmes have described muscle biochemical traits and gene expression levels associated with beef tenderness. One of our results concerning the DNAJA1 gene (an Hsp40) was patented. This study aims to confirm the relationships previously identified between two gene families (heat shock proteins and energy metabolism) and beef quality.

Expression of enzymes and transcription factors involved in n-3 long chain PUFA biosynthesis in limousin bull tissues.

The current low consumption of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) led scientists to wonder about the possible enrichment of human food, including meats such as beef, with n-3 LCPUFA. However, their biosynthesis from dietary n-3 PUFA seems limited in mammalian tissues implying that a better understanding of the molecular mechanisms responsible for this down regulation is needed. This study aimed at identifying and comparing the limiting steps of n-3 LCPUFA synthesis in liver, intermuscular adipose tissue (IM-AT) and semitendinosus muscle (ST) from six Limousin bulls.

Dietary n-3 PUFA affect lipid metabolism and tissue function-related genes in bovine muscle.

Gene expression profiles of bovine longissimus muscle as affected by dietary n-3 v. n-6 fatty acid (FA) intervention were analysed by microarray pre-screening of >3000 muscle biology/meat quality-related genes as well as subsequent quantitative RT-PCR gene expression validation of genes encoding lipogenesis-related transcription factors (CCAAT/enhancer-binding protein β, sterol regulatory element-binding transcription factor 1), key-lipogenic enzymes (acetyl-CoA carboxylase α (ACACA), fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD)), lipid storage-associated proteins (adipose differentiation-related protein (ADFP)) and muscle biology-related proteins (cholinergic receptor, nicotinic, α1, farnesyl diphosphate farnesyl transferase 1, sema domain 3C (SEMA3C)). Down-regulation of ACACA (P = 0·00), FASN (P = 0·09) and SCD (P = 0·02) gene expression upon an n-3 FA intervention directly corresponded to reduced SFA, MUFA and total FA concentrations in longissimus muscle, whereas changes in ADFP (P = 0·00) and SEMA3C (P = 0·05) gene expression indicated improved muscle function via enhanced energy metabolism, vasculogenesis, innervation and mediator synthesis.

Myogenesis is delayed in bovine fetal clones.

We have recently reported that maturation of the skeletal muscle is delayed in cloned calves during their first year postnatally. This delay could originate from perturbations in fetal myogenesis. The aim of this study was to evaluate the developmental characteristics of muscle in clones versus animals derived from conventional reproduction.

Abundance of some skeletal muscle mitochondrial proteins is associated with increased blood serum insulin in bovine fetuses.

The aim of this study was to investigate the evolution of the abundance of cytochrome oxidase c subunit IV (NCOIV) and beta subunit of ATP synthase (β-ATP) during the last third of gestation in bovine skeletal muscles. Semitendinosus, longissimus thoracis and rectus abdominis muscles were chosen for the immunoblotting of the respective protein levels. Muscle and blood samples from bovine fetuses of randomly selected breeds were collected at 180, 210, and 260 days post-conception (dpc).

Molecular profiles of Quadriceps muscle in myostatin-null mice reveal PI3K and apoptotic pathways as myostatin targets.

Background: Myostatin (MSTN), a member of the TGF-beta superfamily, has been identified as a negative regulator of skeletal muscle mass. Inactivating mutations in the MSTN gene are responsible for the development of a hypermuscular phenotype. In this study, we performed transcriptomic and proteomic analyses to detect altered expression/abundance of genes and proteins.